KR20170029610A - Stable organic photosensitive devices with exciton-blocking charge carrier filters utilizing high glass transition temperature materials - Google Patents

Abstract

Disclosed herein are stable organic photosensitive devices comprising one or more exciton blocking charge carrier filters. The filter may be one or more large energy gap materials having a sufficiently high, for example, a temperature or temperature range above which the device typically operates, a glass transition temperature higher than the highest operating temperature of the device, a critical temperature value, And a mixture of one or more electron or hole-conducting materials. As described herein, the novel filter simultaneously excites the excitons and conducts the desired charge carriers (electrons or holes).

Description

FIELD OF THE INVENTION [0001] The present invention relates to a stable organic photosensitive device having an exciton blocking charge carrier filter using a high glass transition temperature material. BACKGROUND OF THE INVENTION < RTI ID = 0.0 > [0001]

Cross-reference to related application

This application claims the benefit of International Application No. PCT / US2014 / 062351, filed October 27, 2014, which is hereby incorporated herein by reference in its entirety, and which is incorporated herein by reference in its entirety, U.S. Provisional Patent Application No. 62 / 026,301, filed on even date herewith.

Federal Government Support STATEMENT OF RESEARCH

The present invention was made with government support under Contract No. DE-SC0000957, DE-SC0001013, and DE-EE0005310, granted by the US Department of Energy, and under FA9550-10-1-0339 granted by the Air Force Science Institute. The government has certain rights to the invention.

Joint research agreement

The subject matter of this disclosure is, on behalf of and / or in connection with the Community Industry Research Agreement, by one or more of the following parties: the Regents of the University of Michigan, the University of Southern California, and NanoFlex Power Corporation Linkage. This Convention is effective on and before the date on which the subject matter of this disclosure is made, and the subject matter of this disclosure is made as a result of activities undertaken within the scope of the Convention.

SUMMARY OF THE INVENTION The present invention is directed to an organophotoreceptive optoelectronic device comprising at least one exciton blocking charge carrier filter comprising a generally energetic, optically active, solar, and semiconductor device, and in particular a wide energy gap material morphologically stable at the operating temperature of the device . Also disclosed herein are methods for making the above.

BACKGROUND OF THE INVENTION Optoelectronic devices rely on the optical and electronic properties of materials that electronically generate or sense electromagnetic radiation, or that generate electricity from ambient electromagnetic radiation.

Photosensitive optoelectronic devices convert electromagnetic radiation into electricity. Solar cells, also known as photovoltaic (PV) devices, are one type of photosensitive optoelectronic devices that are used specifically to generate power. A PV device capable of generating electrical energy from a light source other than sunlight can be used to drive a power consuming load that provides, for example, lighting, heating, or power to an electronic circuit or device such as a calculator, Can be used to power a computer or remote monitoring or communication equipment. This power application is also often used to charge the battery or other energy storage device to continue operation when direct lighting from the sun or other light source is not available, or to balance the power output of a particular PV device with application requirements . As used herein, "resistive load" means any power consumption or storage circuit, device, equipment or system.

Another type of photosensitive optoelectronic device is a photoconductive cell. In this function, the signal sensing circuit monitors the resistance of the device to detect changes due to light absorption.

Another type of photosensitive optoelectronic device is a photodetector. During operation, the photodetector is used in conjunction with a current sensing circuit that measures the current generated when the photodetector is exposed to electromagnetic radiation and has an applied bias voltage. As described herein, the sense circuit may provide a bias voltage to the photodetector and measure the electronic response of the photodetector to electromagnetic radiation.

These three classes of photosensitive optoelectronic devices can be characterized by the presence or absence of rectifying junctions as defined below and also whether the device is operated at an externally applied voltage, also known as a bias or bias voltage. Photoconductive cells do not have rectified junctions and are normally operated with a bias. A PV device has one or more rectifying junctions and is operated without bias. The photodetector has one or more rectifying junctions, but is not always, but is normally operated with a bias. Generally, photovoltaic cells provide power to a circuit, device, or device, but do not provide a signal or current that controls the output of information from the sensing circuit, or the sensing circuit. In contrast, a photodetector or photodiode provides a signal or current that controls the output of information from the sensing circuit, or sensing circuit, but does not provide power to the circuit, device, or equipment.

Traditionally, photosensitive optoelectronic devices have consisted of a large number of inorganic semiconductors, such as crystalline, polycrystalline and amorphous silicon, gallium arsenide, cadmium telluride, and the like. As used herein, the term "semiconductor" refers to a material capable of conducting electricity when induced by thermal or electromagnetic excitation. The term "photoconductive" relates generally to the process by which electromagnetic radiation energy is absorbed, thereby converting the carrier into an excitation energy of the charge carrier so that the carrier can conduct, i.e. transport, the charge. The terms "photoconductor" and "photoconductive material" are used herein to mean a semiconductor material that is selected for its property of absorbing electromagnetic radiation to generate charge carriers.

PV devices can feature the efficiency to convert incident solar power into useful power. Devices using crystalline or amorphous silicon have been noted for commercial applications, with some achieving an efficiency of more than 23%. However, efficient crystalline devices, particularly large surface area devices, are difficult and costly to produce due to inherent problems in producing large crystals without significant efficiency degradation defects. On the other hand, high-efficiency amorphous silicon devices still suffer from problems related to stability. More recent efforts have focused on using organic photovoltaics to achieve economical production costs and acceptable photovoltaic conversion efficiency.

The PV device can be optimized for maximum power generation for maximum multiplication of photocurrent x light voltage under standard lighting conditions (i.e., standard test conditions of 1,000 W / m2, AM 1.5 spectral illumination). Under normal lighting conditions, the power conversion efficiency of the battery depends on the following three parameters: (1) current under zero bias, i.e. short-circuit current I _SC (amperes) (2) Voltage V _OC (volts) and (3) fill factor ( FF ).

When connected across a load, a PV device generates an optically generated current and is illuminated by light. When illuminated under an infinite load, the PV device generates its maximum possible voltage, V open circuit, or V _OC . When illuminated with its shorted electrical contacts, the PV device generates its maximum possible current, I short, or I _SC . When actually used to generate power, the PV device is connected to a finite resistive load and the power output is provided by the product of current and voltage (I x V). The maximum total power generated by the PV device can not uniquely exceed the I _SC x V _OC product. If the load value is optimized for maximum power extraction, the current and voltage have I _max and V _max, respectively.

An important feature of PC devices is the fill factor ( f f ) defined as:

FF = {I _max V _max } / {I _SC V _OC } (1)

Since I _SC and V _OC are never obtained at the same time in practical use, FF is always less than 1. Nevertheless, as FF approaches 1, the device has fewer series or internal resistances, thereby delivering a larger ratio of I _SC and V _{OC to} the load under optimal conditions. If P _inc is the power incident on the device, the power efficiency ? _P of the device can be calculated as:

η _P = FF * (I _SC * V _OC ) / P _inc .

In order to create an internally generated electric field that occupies a considerable volume of semiconductor, a common method is to juxtapose two material layers with appropriately selected conductivities, particularly in terms of the distribution of molecular quantum energy states. The interface between these two materials is called a photovoltaic junction. In traditional semiconductor theories, materials that form PV junctions have generally been denoted n-type or p-type. Herein, the n type means that the main carrier type is the former. It can be illuminated as a material with multiple electrons in a relative free energy state. The p-type implies that the main carrier type is hole. The material has a plurality of holes in a relative free energy state. The background type, i. E., The majority of the un-photo-generated carrier concentration, is mainly dependent on unintended doping by defects or impurities. The type and concentration of the impurity determines the value of the Fermi energy or level within the gap between the conduction band minimum energy and the valence band maximum energy, also known as the HOMO-LOMO gap. The Fermi energy is characterized by the statistical occupation of the molecular quantum energy state indicated by an energy value with an occupancy probability of ½. The Fermi energy close to the conduction band minimum (LUMO) energy indicates that the electron is the predominant carrier. The Fermi energy close to the valence band maximum (HOMO) energy indicates that the hole is dominant. Thus, Fermi energy is the main characterization of traditional semiconductors, and typical PV junctions are traditionally p-n interfaces.

The term "rectifying" specifically means that the interface has asymmetric conduction characteristics, i.e., the interface preferably supports charge transport in one direction. Rectification is generally associated with an internal electric field occurring at the junction between appropriately selected materials.

A significant property of organic semiconductors is carrier mobility. Mobility is a measure of the ease with which a charge carrier can move through a conductive material in response to an electric field. In the context of organic photosensitive devices, a layer comprising a material that is preferentially electron-conductive due to its high electron mobility may be referred to as an electron transport layer or ETL. A layer comprising a material that is preferentially transported by holes due to high hole mobility may be referred to as a hole transport layer or HTL. In some cases, the receptor material may be ETL and the donor material may be HTL.

Conventional inorganic semiconductor PV cells can establish built-in electric fields using p-n junctions. However, in addition to establishing a p-n type junction, it is now recognized that the energy level offset of the heterojunction also plays an important role.

In organic donor-acceptor (DA) heterojunctions, energy level offsets are believed to be important for the operation of organic PV devices due to the basic nature of the photogeneration process in organic materials. Upon optical excitation of the organic material, localized Frenkel or charge transfer excitation occurs. In order for electrical sensing or current generation to occur, the coupled excitons must be dissociated into their constituent electrons and holes. The process can be induced by a built-in electric field, but the efficiency in an electric field that is commonly found in organic devices (F ~ 10 ⁶ V / cm) is low. The most efficient exciton dissociation in organic materials occurs at the DA interface. At the interface, the donor material with a low ionization potential forms a heterojunction with the acceptor material with high electron affinity. Depending on the alignment of the energy levels of the donor and acceptor materials, dissociation of the excitons may be energetically favorable at the interface, thereby inducing free-electron polaron in the free electron polaron and the donor material in the acceptor material.

Carrier generation requires exciton generation, diffusion and ionization or collection. There is an efficiency η associated with each of these processes. The subscripts can be used with: P is power efficiency, EXT is external quantum efficiency, A is photon absorption, ED is diffusion, CC is collection, and INT is internal quantum efficiency. Using the above notation,

η _{p  ~} η _EXT  = η _A  * η _ED  * η _CC

η _EXT = η _A * η _INT .

The diffusion length (L _D ) of the excitons is typically much less than the optical absorption length (~ 500 A) (L _D ~ 50 A), which is either thicker and therefore resistant to multiple or highly overlapped interfacial cells, And requires a trade-off between using a thin battery having a low absorption efficiency.

Organic PV cells have many potential advantages when compared to traditional silicon-based devices. Organic PV cells can be deposited on substrates, such as flexible plastic foils, which are lightweight, economical to use, and cost-effective. However, for commercialization, device efficiency must be further improved through new material and device design approaches.

In organic PV cells, it can be observed that interfacial phenomena dominate the behavior of important processes, such as charge separation at the donor / acceptor interface and charge extraction at the organic / electrode interface. To suppress exciton recombination, a buffer layer is often used between the photoactive region and one or both of the two electrodes to enhance charge extraction.

Wide energy gap materials such as BCP and BPhen have been used as buffers. The material acts by blocking exciton transport due to its broad HOMO-LUMO energy gap, while transporting electrons through a defect state induced by the deposition of the cathode. The second action of the wide gap buffer is to further isolate the optical absorption layer from the reflective cathode at the optimal location in the optical field. However, the buffer is highly resistant to polarized films (<10 nm) due to the penetration depth of the defect states accumulated during deposition.

A small HOMO energy source, such as Ru (acac), has been used as a buffer to recombine with electrons at the receptor / buffer interface by transporting holes from the cathode.

A third type of buffer has been developed in which the LUMO energy is based on a material aligned with that of a receptor, such as, for example, PTCBI and NTCDA. Through alignment of the LUMO energy, the electrons can be efficiently conducted from the receptor to the cathode. This material can also act to block the exciton if its HOMO / LUMO gap is large enough. However, the material may interfere with device performance if it absorbs in the same spectral range as the active layer material. In order to increase the conversion efficiency of the organic PV cell, an improvement to the device structure must be made.

The present inventors have developed a novel type of buffer disclosed herein as an exciton blocking charge carrier filter. Such novel buffering agents comprise one or more of a wide energy gap material and a mixture of one or more electron or hole conductive materials. The filter is optimized depending on its position in the device. That is, the exciton blocking hole conduction filter is disposed between the photoactive region and the anode to block the excitons and to conduct holes to the anode. Conversely, an exciton blocking electron conductive filter is disposed between the photoactive region and the cathode to block the exciton and to conduct electrons to the cathode. For example, in an exciton-blocking electronic filter, electrons are transported by an electron-conducting material through an impurity band-like mechanism. At the same time, the excitons are blocked by a combination of an energy barrier caused by a broad energy gap material and a statistical barrier caused by a reduction in the number of states available for delivery to the electron conductor.

For example, the problem with a large number of buffers such as BCP or BPhen is that the buffer is highly resistant and depends on the damage induced transport condition which limits the actual layer thickness to ~ 10 nm. By mixing a wide energy gap material (e.g., BCP) and a material having excellent transport properties (e.g., C ₆₀ ), the overall conductivity can be improved using impurity band-like transport.

A second problem with the use of buffering agents such as BCP or Bphen is that in some cases it may be morphologically unstable at the operating temperatures at which their respective glass transition temperatures (T _g ) are reached or, in some cases, , Which can contribute to performance degradation over time, which significantly reduces the operating life of the device. Under these conditions, the buffer can crystallize and decompose. The present inventors have found that a wide energy gap material is mixed with an electron conductor (e. G., Fullerene) or a hole conductor such that the buffer layer similarly increases stability to "doped pinning" Further, by using a wide energy gap material that is formally stable, i.e., a wide energy gap material having a sufficiently high glass transition temperature, the operating life of the device can be extended sufficiently in the exciton-blocking charge carrier filter described herein .

The exciton-blocking charge carrier filter described herein also serves to prevent accumulation of charge in the active layer which helps to reduce the exciton polaron quenching of the excitons, while increasing the short-circuit current and the fill factor of the device.

In a first aspect of the present disclosure, an organophotoreceptive optoelectronic device comprises two electrodes comprising an anode and a cathode in an overlapping relationship; Donor-optically active region (herein, at least one acceptor material is the lowest unoccupied molecular orbital energy level (LUMO _Acc) and the top containing at least one donor material and at least one acceptor material disposed between two electrodes, to form an acceptor heterojunction One or more donor materials have a lowest unoccupied molecular orbital energy level (LUMO _don ) and a highest occupied molecular orbital energy level (HOMO _don ), with occupied molecular orbital energy levels (HOMO _Acc ); And an exciton blocking electronic filter disposed between the cathode and the at least one receiver material, wherein the electronic filter comprises a mixture comprising at least one wide energy gap material on the one or more cathode sides and one or more electronically conductive materials, The wide energy gap material of

- the lowest unoccupied molecular orbital energy level (LUMO _CS-WG ) less than or equal to LUMO _Acc ;

- the highest occupied molecular orbital energy level (HOMO _CS-WG ), which is less than, equal to, or less than, 0.3 eV HOMO _Acc ; And

- HOMO _Acc - LUMO _ACC has wider energy gap than HOMO _{CS - WG -} LUMO _{CS - WG with} energy gap;

Wherein the wide energy gap material at one or more cathode sides has a glass transition temperature of 85 DEG C or higher.

In a second aspect, an organophotoreceptive optoelectronic device includes two electrodes comprising an anode and a cathode in an overlapping relationship; A photoactive region comprising at least one donor material and at least one donor material disposed between the two electrodes forming a donor-acceptor heterojunction wherein the at least one donor material has a lowest unoccupied molecular orbital energy level (LUMO _don ) and a peak Having an occupied molecular orbital energy level (HOMO _don )); And an exciton blocking hole filter disposed between the anode and the at least one donor material, wherein the hole filter comprises a mixture comprising at least one wide energy gap material on the anode side and one or more hole-conducting materials, wherein the one or more anode side The wide energy gap material of

- greater than HOMO _don , or such highest occupied molecular orbital energy level (HOMO _AS-WG ) energy level;

- LUMO _AS-WG higher minimum occupied molecular orbital energy level within 0.3 eV, less than, equal to, or greater than LUMO _don (farther from vacuum); And

- HOMO _don -LUMO _don has larger energy gap than HOMO _AS-WG -LUMO with _AS-WG energy gap;

Wherein the broad energy gap material at one or more anode sides has a glass transition temperature of 85 [deg.] C or higher.

The accompanying drawings are included to compose and constitute a part of this specification.
BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 shows a schematic diagram of an exemplary organic photosensitive optoelectronic device according to the present disclosure. Device A includes an exciton blocking electronic filter or exciton blocking hole filter, and device B includes an exciton blocking electron filter and exciton blocking hole filter.
FIG. 2 is a graph showing the relationship between the volume doping ratios calculated from k measured by spectroscopic ellipsometry and 1: 0 (), 3: 1 (), 1: (B) shows the extinction spectrum of C ₆₀ : BCP film. Explosion attenuation as a function of extinction spectrum. 450 nm (?), 360 nm (?).
Figure 3 shows a plot of external quantum efficiency at the bottom with a bottom plot showing the device geometry and the JV curve of the device at the top 1 sun AM 1.5G light with top plot showing device characteristics. (A: B) = 1: 0 (D1), 2: 1 (D2), 1: 1 (D3), and 1: 2 (D4).
Figure 4 shows a plot of the external quantum efficiency at the bottom with a plot showing the device's structure and the JV curve of the device under 1 sun AM 1.5G illumination at the top. x = 10 nm (D7), 20 nm (D6), 30 nm (D5).
Figure 5 shows a plot of external quantum efficiency at the bottom with a plot showing the device's structure and the JV curve of the device under 1 sun AM 1.5G illumination at the top. x = 0 nm (D8), 20 nm (D9), and 40 nm (D10).
Figure 6 shows a plot of the external quantum efficiency at the bottom with a plot showing the device's structure and the JV curve of the device under 1 sun AM 1.5G illumination at the top. "Initial C ₆₀ thickness" refers to the thickness of one or more receptor materials that form donor-receptor heterozygosity with DPSQ (x = 5 nm, 15 nm, 25 nm, 35 nm).
Figure 7 shows the external quantum efficiency of the bottom, with the bottom plot showing the device geometry and JV curve of the device under 1 sun AM 1.5G illumination at the top.
Figure 8 shows the external quantum efficiency under the applied bias (+0.5 V dashed line, -1 V solid line) for various buffer layers normalized to EQE at zero bias.
Figure 9 is a plot of the distribution of BCP: C _{60 on} top of the pure C ₆₀ active layer of the exciton, based only on the reduced number of C ₆₀ molecules in the mixed film available for exciton transfer, It shows the simulation. The excitons are randomly generated in the active layer. After moving to a random number of steps, its final position is recorded. It is assumed that this is spread only by nearest neighbor hopping. At the interface between the mixed layer and the active layer, the probability of hopping between layers is scaled by the relative number of C ₆₀ molecules in each layer.
The top of FIG. 10 shows the normalized extinction spectrum of C ₇₀ capped with different buffer layers and the bottom shows the quenching (NPD) at the bottom, the blocking (BCP), and the capped _Which is the emission spectrum of C ₇₀ .
Figure 11 shows the EQE spectrum (top) of a device capped with various buffer layers and the JV curve of a device under 0.8 sun AM 1.5G illumination.
Figure 12 shows a plot of the JV curve of the device under 1 sun AM 1.5G illumination at the top and the external quantum efficiency at the bottom, where the bottom figure shows the device structure. Buffer: 10 nm BCP (D11), 10 nm C 60: BCP (D12), 10 nm PTCBI (D13), 10 nm C 60: BCP / 5 nm PTCBI (D14), 10 nm BCP: C 60/5 nm BCP (D15).
The top of FIG. 13 shows the EQE for the device of FIG. 12 with various buffer layers at -1 V normalized to 0 V EQE and the bottom shows the response as a function of illumination for the device. Buffer: 10 nm BCP (D11), 10 nm BCP: C 60 (D12), 10 nm PTCBI (D13), 10 nm BCP: C 60/5 nm PTCBI (D14), 10 nm BCP: C 60/5 nm BCP (D15).
Figure 14 shows a plot of the JV curve of the device under 1 sun AM 1.5G illumination at the top and the external quantum efficiency at the bottom where x = 5 nm (D16), 15 nm (D17), 25 nm (D18), and 35 nm (D19), respectively.
Figure 15 shows a plot of the external quantum efficiency of a device with various buffer layers and a JV curve under 1 sun AM 1.5G illumination at the top.
Figure 16 shows a plot of the external quantum efficiency of a device having various buffer layers containing a JV curve under 1 sun AM 1.5G illumination at the top and various ratios of C ₆₀ versus BCP.
17 is relatively thick, 1: 8 by volume with DBP and C for a plane mixed OPV cell having an active layer comprising a layer of the net _70, JV (upper left) for the illumination of at 1 sun simulated AM 1.5G one trillion people And EQE (top right) and extracted efficiency parameters (bottom). The thickness and volume ratios of BPhen: C ₇₀ for each buffer are given in the table.
FIG. 18 is a plot of the JV (%) versus time for illumination in a 0.7 sun simulated AM 1.5G illumination for a planar mixed OPV cell with an active layer comprising a net layer of DBP and C ₇₀ and a variable buffer in a relatively thin 1: Upper left) and EQE (upper right) and extracted efficiency parameters (lower). The thickness and volume ratios of BCP: C ₇₀ for each buffer are given in the table.
Figure 19 shows EQE and JV curves for dilution using BPhen, CBP, and UGH2.
Figure 20 (a) is a DBP: it shows the simulated spectrum of AM 1.5G, 1 sun jomyeongha correction current density vs. voltage (JV) features about C ₇₀ mixed HJ OPV cell. The shaded area highlights the difference in the fill factor of the two cells, and thus the maximum power output. The illustration shows a schematic diagram of the device structure and (b) shows the external quantum efficiency (EQE) spectrum for the cell of (a) . The insert shows a schematic diagram of the energy levels at the DBP: C ₇₀ / buffer interface (left: pure BPhen buffer; right: BPhen: C ₆₀ compound buffer).
Figure 21 shows the response versus luminosity for mixed HJ control cells and compound buffer cells, where the linear pits are in accordance with the bicomponent recombination theory (dashed line).
Figure 22 (a) shows the charge extraction time versus electric field for various layer thicknesses, calculated using a 3D Monte Carlo simulation. Sapdo is as showing a large thickness cell series resistance (R _s), wherein a linear fit (dashed line) is for the data (square mark) obtained from OPV cell (in sapdo error bars are smaller than the data points), ( b) shows the photoluminescence (PL) spectrum for the net C ₇₀ layer contacted with the BPhen (blocking), NPD (quenching) and BPhen: C ₆₀ mixed layers obtained at the excitation wavelength of? = 520 nm.
Figure 23 (a) shows spectrally corrected current density vs. voltage (JV) characteristics under simulated AM 1.5G, 1 sun illumination, (b) shows DBP: C ₇₀ PM-HJ OPV cells with buffer layer It shows the quantum efficiency spectrum.
24 is a control cell and BPhen: to show an absorption spectrum and an internal quantum efficiency is calculated for a cell having a C ₆₀ / BPhen buffer.
25 is a control cell and BPhen: to show the light intensity versus C ₆₀ / BPhen reaction for the cell having a buffer (black square), and the power conversion efficiency (white square mark).
Figure 26 (a) shows spectrally corrected JV characteristics under simulated AM 1.5G, 1 sun illumination and (b) shows the thickness of the BPhen: C ₆₀ mixed layer in a cell with BPhen: C ₆₀ / BPhen buffer Lt; RTI ID = 0.0 &gt; quantum &lt; / RTI &gt; efficiency spectrum as a function.
27 is BPhen: C ₆₀ as a function of the mixed layer thickness will show the extracted median time for the electric field, sapdo is to show a series resistance for the mixed layer thickness by using the fitting.
Figure 28 (a) shows the JV for illumination under 1 sun simulated AM 1.5G illumination, where the illustration shows NPD, (b) shows an OPV cell with DBP and C ₆₀ and an active layer composed of various buffers Lt; RTI ID = 0.0 &gt; quantum efficiency. &Lt; / RTI &gt;
29 shows a schematic of an exemplary stacked organic photosensitive optoelectronic device according to the present disclosure. Device A comprises an exciton-blocking electronic filter or an exciton-blocking hole filter, and device B comprises an exciton-blocking electron filter and an exciton-blocking hole filter.
30 shows a mixed BPhen: C ₆₀ buffer layer (10 nm) with a thin BPhen cap layer (5 nm) between the mixed buffer layer and the Al electrode, or alternatively a thin Shows a DBP: C ₇₀ device with a mixed TPBi: C ₇₀ buffer layer (10 nm) having a TPBi cap layer (3 nm).
Figure 31a to 31c are the Bphen mixture having a thin BPhen cap layer: the normalized reactions over time in each of 50 ℃ for the device of C ₆₀ buffer layer is 30 comprising, 60 ℃, and 80 ℃, fill factor, V _OC , and PCE.
Figure 32a to 32d are mixed in the thin TPBi cap layer TPBi: C normalized reactions over time in the ₆₀ respectively 50 ℃, 80 ℃ for the device of Figure 30 having the buffer layer, and 105 ℃, and 130 ℃, Phil Factor, V _OC , and PCE.
Figure 33 shows the normalized power conversion efficiency over time for DBP: C ₇₀ mixed heterogeneous junctions using various buffers.
34 to 38 shows the molecular structure of each of the exemplary wide energy gap material _{BAlq, TPBi, Alq 3, BP4mPy} , and 3TPYMB.
Figure 39-41 are C ₇₀ and each TPBi, 3TPYMB, BAlq and the normalized response of from 55 ℃ with time for a device having a buffer mixture containing one or a mixture of, fill factor, V _OC, and PCE .
Figure 42 shows a DBP: C ₇₀ device with a mixed 3 TPYMB: C ₆₀ buffer layer.
Figures 43-46 show normalized reactivity, fill factor, V _OC , and PCE over time for the divergence of Figure 42 at 55 ° C, 70 ° C, 85 ° C, and 100 ° C, respectively.

As used herein, the term "organic" includes small molecular organic materials as well as polymeric materials that can be used to fabricate organic photosensitive devices. By "small molecule" is meant any organic material that is not a polymer, and "small molecule" may actually be very large. Small molecules may contain repeat units in some circumstances. For example, using a long chain alkyl group as a substituent does not remove one molecule from the "small molecule" class. Small molecules may also be incorporated into the polymer, for example, as a pendant group on the polymer backbone, or as part of the backbone.

The terms "donor" and "receptor" are used herein to refer to the relative positions of the highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) energy levels of two different organic materials Quot; If the LUMO energy level of a substance in contact with another is far away from the vacuum level, then the substance is a receptor. Otherwise, it is a donor, which is energetically favorable for electrons in the donor-acceptor junction to migrate to the acceptor material under the absence of an external bias, and to transfer holes to the donor material.

In the present application, the term "cathode" is used in the following manner. In a single unit of a non-stacked PV device or stacked PV device, such as a solar cell, connected by a resistive load under ambient illumination and without an externally applied voltage, electrons move from the adjacent photoconductive material to the cathode. Similarly, the term "anode " is used here in a solar cell under illumination to move a hole from the adjacent photoconductive material to the anode, which is equivalent to electrons traveling in the opposite manner. It should be noted that the "anode" and "cathode" electrodes may be those used in charge transfer regions and recombination zones, e.g., stacked photovoltaic devices.

In a photosensitive optoelectronic device it may be desirable to allow a maximum amount of ambient electromagnetic radiation from outside the device to the photoconductive active interior area. That is, the electromagnetic radiation must reach the photoconductive layer (s), where it can be converted to electricity by photoconductive absorption. This often indicates that one or more of the electrical contacts must absorb and at least reflect incident electromagnetic radiation. In some cases, the contacts should be transparent, or at least translucent. The electrode is referred to as "transparent" if at least 50% of the ambient electromagnetic radiation at the wavelength of interest is allowed to pass through it. The electrode is said to be "translucent" when it transmits some of the ambient electromagnetic radiation at the relevant wavelength, but transmits less than 50%. The opposite electrode may be a reflective material so that light that is not absorbed and passes through the cell is reflected back through the cell.

As used herein, "photoactive region" means an area of a device that absorbs electromagnetic radiation to generate excitons. Similarly, if a layer absorbs electromagnetic radiation to generate an exciton, it is "photoactive ". The excitons can be dissociated into electrons and holes to generate electrical current.

As used and shown here, the term "layer " means a member or component of a photosensitive device whose one dimension is X-Y, i.e., its length and width. It should be understood that the term layer need not necessarily be limited to a single layer or sheet of material. In addition, certain surfaces, including the interface (s) of the layer comprising other material (s) or layer (s), may be defective, where the surface may include other material (s) Quot; is intended to denote a network of interpenetrating, entangled, or convoluted networks. Similarly, it should also be understood that the layer may be discontinuous and, therefore, the continuity of the layer with respect to the XY dimension may be disturbed or otherwise interrupted by other layer (s) or material (s) do.

As used herein, a first HOMO or LUMO energy level is "less than a second HOMO or LUMO energy level " if the first HOMO or LUMO energy level is closer to a vacuum level than a second HOMO or LUMO energy level . Similarly, if the first HOMO or LUMO energy level is farther away from the vacuum level than the second HOMO or LUMO energy level, the first HOMO or LUMO energy level is "greater than the second HOMO or LUMO energy level ".

As used herein, when the energies of two orbital energy levels coincide to the first decimal place, the two orbital energy levels are "identical" For example, for the purposes of this disclosure, a LUMO energy of -3.70 eV will be considered "equal" to a LUMO energy of -3.79 eV.

As used herein, LUMO _Acc and HOMO _Acc each represent the lowest unoccupied molecular orbital energy level and the highest occupied molecular orbital energy level of one or more receptor materials.

As used herein, LUMO _don and HOMO _don each represent the lowest unoccupied molecular orbital energy level and the highest occupied molecular orbital energy level of one or more donor materials.

As used herein, LUMO _{CS - WG} and HOMO _{CS - WG} each represent the lowest unoccupied molecular orbital energy level and the highest occupied molecular orbital energy level of a wide energy gap material on at least one cathode side.

As used herein, LUMO _{AS - WG} and HOMO _{AS - WG} each represent the lowest unoccupied molecular orbital energy level and the highest occupied molecular orbital energy level of the wide energy gap material on at least one anode side.

As used herein, LUMO _EC and HOMO _EC each represent the lowest unoccupied molecular orbital energy level and the highest occupied molecular orbital energy level of at least one electron conductive material.

As used herein, LUMO _HC and HOMO _HC each represent the lowest unoccupied molecular orbital energy level and the highest occupied molecular orbital energy level of at least one hole-transporting material.

As used herein, the HOMO-LUMO energy gap is the energy difference between the HOMO and LUMO of the material.

As used herein, the term "between" in the context of an enumerated range of glass transition temperatures (T _g ) for a wide energy gap material is meant to include an endpoint value.

The device of the present disclosure comprises at least one exciton blocking charge carrier filter. For example, a schematic diagram of an organic photosensitive optoelectronic devices of the present disclosure is shown in FIG. The electrode 110 includes an anode or a cathode. Electrode 140 includes an anode when electrode 110 comprises a cathode. Electrode 140 includes a cathode when electrode 110 comprises an anode. As described herein, the photoactive region comprises donor / acceptor organic layers 120 and 130 to form donor-acceptor heteromeric junctions. The photoactive region may comprise additional donor and / or receptor layers to form, for example, a hybrid planar-mixed heterogeneous junction. The organic layer 120 comprises one or more donor materials or one or more acceptor materials. The organic layer 130 includes one or more donor materials when the layer 120 comprises one or more receptor materials. The organic layer 130 includes one or more receptor materials when the layer 120 comprises one or more donor materials. Note that the donor / receptor layer of Figure 1 need not be planar. That is, the present disclosure contemplates all types of donor-acceptor heterojunctions known in the art for organic photovoltaic devices, including those specifically described herein.

In the device A of FIG. 1 , the layer 115 is formed by depositing an electrode 110 on a substrate 110 , where the electrode 110 comprises a cathode, the organic layer 120 comprises one or more receptor materials, the organic layer 130 comprises one or more donor materials, When the electrode 140 comprises an anode, it is an exciton blocking electronic filter. Layer 115 is the cathode electrode 110 is an anode, and an organic layer 120, and electrode 140 comprises a comprises at least one donor material, and the organic layer 130 is at least one acceptor material When included, it is an exciton blocking hole filter.

In some embodiments, a device such as device B includes both an exciton blocking electron filter and an exciton blocking electron filter. Layer 115. The electrode 110 is included, and the organic layer 120 comprises comprises at least one acceptor material, and the organic layer 130 is at least one donor material, and layer 135 is the exciton block the cathode Hole filter, and when the electrode 140 includes an anode, it is an exciton blocking electronic filter. Layer 115. The electrode 110 is included, and the organic layer 120 comprises comprises at least one donor material, and the organic layer 130 is at least one acceptor material, and layer 135 the exciton blocking anode Electron filter, and when the electrode 140 includes a cathode, it is an exciton blocking hole filter.

Although not shown in FIG. 1 , devices A and B may include an additional buffer layer or cap layer located between the closest electrodes of the exciton blocking electron / hole filter.

An exciton-blocking electronic filter is disposed between the cathode and one or more receptor materials, and comprises a mixture comprising at least one cathode-wide wide energy gap material and at least one electron conductive material. The wide energy gap material on one or more cathode sides

- the lowest unoccupied molecular orbital energy level (LUMO _CS-WG ) less than or equal to LUMO _Acc ;

- the highest occupied molecular orbital energy level (HOMO _CS-WG ), which is less than, equal to, or less than, 0.3 eV HOMO _Acc ; And

- it has a large _{HOMO-CS-CS WG} -LUMO _WG energy gap than a HOMO energy gap _{Acc Acc} -LUMO.

At least one electron-conductive material has a less than 0.3 eV greater than the LUMO _Acc, or equal to the, or rather smaller, for example, the smaller the lowest unoccupied molecular orbital energy level (LUMO _EC) less than 0.2 eV.

In order to extend the operating lifetime of the device by utilizing a morphologically stable material, some embodiments of the present invention may provide a device that is sufficiently high, e.g., higher than the temperature or temperature range at which the device typically operates, A wide energy gap material on the cathode side having a glass transition temperature higher than the critical temperature value or the like is used.

In some embodiments, the HOMO _{CS - WG} is greater than HOMO _Acc , for example greater than 0.2 eV, greater than 0.3 eV greater, greater than 0.5 eV greater, greater than 1 eV greater, greater than 1.5 eV greater For example, less than 0.2 eV, less than 0.3 eV, less than 0.5 eV, less than 1 eV, or more than 2 eV, and LUMO _{CS - WG} is smaller than LUMO _Acc , Less than 1.5 eV, or less than 2 eV.

In some embodiments, LUMO _EC is equal to LUMO _Acc .

In some embodiments, LUMO _EC is greater than LUMO _Acc , e.g., greater than 0.5 eV, greater than 0.4 eV greater, greater than 0.3 eV greater, or less than 0.2 eV.

In some embodiments, LUMO _EC is less than or greater than 0.1 eV below LUMO _Acc .

In some embodiments, LUMO _{CS - WG} is smaller than LUMO _EC , e.g., LUMO _EC , such as less than 0.2 eV, less than 0.3 eV, less than 0.5 eV, or less than 1 eV Less than 1.5 eV, or less than 2 eV.

In some embodiments, the LUMO _{CS - WG} is less than 0.2 eV above the LUMO _Acc , e.g., less than 0.3 eV, less than 0.5 eV, less than 1 eV, less than 1.5 eV , Or smaller than 2 eV.

In some embodiments, the wide energy gap material on one or more cathode sides is selected from the group consisting of Bottokuproin (BCP), Batophenanthroline (BPhen), p -Bis (triphenylsilyl) benzene (UGH-2) (CBP), N, N'-dicarbazolyl-3,5-benzene (mCP), poly (vinylcarbazole) (PVK), phenanthrene and alkyl and / Or aryl substituted phenanthrene, alkyl and / or aryl substituted derivatives of benzene, triphenylene and alkyl and / or aryl substituted triphenylene, aza-substituted triphenylene, oxydiazole, triazole, Diaryl, adamantane and alkyl and / or aryl substituted adamantanes, tetraarylmethane and its derivatives, 9,9-dialkyl-fluorene and its oligomers, 9,9-diaryl-fluorene and its oligomers, Spiro-biphenyl and substituted derivatives thereof, corannulene and alkyl and / or aryl substituted derivatives, and derivatives thereof.

62℃)의 혼합물을 포함하는 엑시톤-차단 전하 캐리어 필터의 시간에 따른 성능(즉, 정규화된 반응도, 필 팩터, Voc, 및 PCE)은 작동 온도가 50℃ 내지 130℃로 증가하는 TPBi:C₇₀ (TPBi의 T_g

122℃)의 혼합물을 포함하는 엑시톤-차단 전하 캐리어 필터보다 더 빠르게 작동 온도가 50℃ 내지 80℃로 증가함에 따라 저하된다. 즉, TPBi:C₇₀을 이용하는 디바이스의 성능은 BPhen을 이용하는 디바이스보다 고온의 작동 온도에서 시간에 따라 보다 서서히 저하된다. 따라서, 디바이스의 효율 및 작동 수명은 예를 들면 유사한 T_g 값을 갖는 Bphen 및 차단 물질을 더 높은 T_g를 갖는 캐소드 측의 에너지 갭 물질, 예컨대 TPBi로 대체함으로써 개선될 수 있다. The operational lifetime of the device can be extended, for example, to a wide range of the cathode side having a sufficiently high T _g such as higher than the temperature or temperature range at which the device normally operates, higher than the highest operating temperature of the device, Can be increased by using an energy gap material. For example, as shown in Figures 31a-c and 32a-d , Bphen: C ₆₀ (T _{g of} Bphen

(Normalized reactivity, fill factor, Voc, and PCE) of the exciton-blocking charge carrier filter comprising a mixture of TPBi: C ₇₀ (T _{g of} TPBi

Lt; RTI ID = 0.0 &gt; 50 C &lt; / RTI &gt; to &lt; RTI ID = 0.0 &gt; 80 C. &lt; / RTI &gt; That is, the performance of a device using TPBi: C ₇₀ degrades more slowly over time at higher operating temperatures than devices using BPhen. Thus, the efficiency and operating life of the device can be improved, for example, by replacing Bphen with a similar T _g value and the barrier material with an energy gap material on the cathode side with a higher T _g , such as TPBi.

In some embodiments, the energy gap material on one or more cathode sides is sufficiently high such as, for example, higher than the temperature or temperature range at which the device normally operates, higher than the highest operating temperature of the device, T _g . &Lt; / RTI &gt; For example, in some embodiments, the wide energy gap material on one or more cathode sides is selected from the group consisting of 3,3 ', 5,5'-tetra [(m-pyridyl) (1-phenyl-1-H-benzimidazole) (TPBi), bis (2-methyl-8-quinolinol Tris (8-hydroxy-quinolinato) aluminum (Alq3), tris (2,4,6-trimethyl-3- (pyridin- Phenyl) borane (3TPYMB), 4,40- (1,3-phenylene) bis (2,6-diphenylpyridine-3,5-dicarbonitrile) (M-PhPyCN), 4,40- (1,3-phenylene) bis (2,6-di (biphenyl-4-yl) pyridine-3,5-dicarbonitrile (2,6-diphenylpyridine-3,5-dicarbonitrile) (m-PyCN), 6,60- (1,4-phenylene) (p-PPtNN), 4,40- (1,4-phenylene) bis (2-phenyl-6-p-tolylnicotinonitrile) (p- PPtNT), tris (6-fluoro-8- -Quinolinato) aluminum (6FAlq3), 2,6-bis (4- 4,5-dicarbonitrile (CNPyCN), 4,40- (1,4-phenylene) bis (2,6-diphenylpyridine- (p-MPyCN), bisbenzimidazo [2,1-a: 1 ', 2-b'] anthra [2,1,9-def: 6,5,10- 5,10,15-tribenzyl-5H-diindolo [3,2-a: 3 ', 2'-c] carbazole (TBDI), 5,10 (3,5-di (pyridin-3-yl) -1H-pyrazolo [3,4-d] pyrimidin- Phenyl] benzene (BmPyPhB), 1,3,5-tris (m-pyridin-3-ylphenyl) benzene, 1,3,5- (TmPyPB), 9,9-dimethyl-benzo [b] thiophene-3,3'- (MCBP), 3,3-di (9H-carbazol-9-yl) biphenyl (mCBP) , 4,40-bis (triphenylsilyl) -biphenyl (BSB), and derivatives thereof.

In some embodiments, the glass transition temperature of the wide energy gap material on the cathode side is greater than or equal to 85 ° C, greater than or equal to 95 ° C, greater than or equal to 105 ° C, greater than or equal to 115 ° C, greater than or equal to 125 ° C, greater than or equal to 135 ° C, At least 175 占 폚, at least 185 占 폚, at least 195 占 폚, at least 200 占 폚, at least 225 占 폚, or at least 250 占 폚.

In some embodiments, the glass transition temperature of the wide energy gap material on the cathode side is 85-200 DEG C, such as 90-195 DEG C, 95-190 DEG C, 100-185 DEG C, 105-180 DEG C, 110-175 DEG C, 170 ° C, or 120-165 ° C. It is noted that materials having a glass transition temperature of greater than 200 ° C, such as 200-300 ° C, 200-275 ° C, 200-250 ° C, or 200-225 ° C, may be used.

The operating temperature of the device can be varied and can be varied by a number of factors such as ambient conditions (e.g., temperature, light intensity, etc.) and a reinforcement mechanism (e.g., Depending on whether it is used or not. By way of example, the ambient temperature may vary depending on the geographic location of the device, the year of the year, the day of the week, and so on. Likewise, light intensity may also depend on cloudiness, angle of incidence and other factors, as well as geographical location, year-round time, and daylight time. Thus, in some embodiments, the wide energy gap material on the cathode side can be used as a material for a device, for example, under a general ambient condition, etc., where the device is operating above (e.g., Has a sufficiently high T _g that is higher than the maximum operating temperature.

In some embodiments, the solar thermal concentrator may be integrated into or coupled to the device to increase, magnify, or otherwise increase the light applied to the device. The use of a light concentrator and / or other reinforcement may increase the operating temperature of the device beyond that occurring in the device under normal ambient conditions. Thus, in order to increase the stability and operating life of the device, the wide energy gap material on the cathode side may have a higher T _g than the highest operating temperature occurring in the device under increased illumination conditions.

In some embodiments, the one or more receptor materials are selected from the group consisting of subphthalocyanine, subnaphthalocyanine, dipyrin complexes such as zinc dipyrrhin complex, BODIPY complex, perylene, naphthalene, fullerene and fullerene derivatives (e.g. PCBM, ICBA, And polymers containing polymers such as carbonyl-substituted polythiophenes, cyano-substituted polythiophenes, polyphenylene vinylenes, or electron-deficient monomers such as perylene diimide, benzo-thiadiazole, or fullerene &Lt; / RTI &gt; polymers. But are not limited to C ₆₀ , C ₇₀ , C ₇₆ , C ₈₂ , C ₈₄ or derivatives thereof such as phenyl-C ₆₁ -butyric acid-methyl ester ([60] PCBM), phenyl-C ₇₁ -butyric acid-methyl ester ([70] PCBM), or thienyl-C ₆₁ -butyric acid-methyl ester ([60] ThCBM), and other receptors such as 3,4,9,10-perylenetetracarboxylic-bisbenzimidazole PTCBI), hexanedecafluorophthalocyanine (F ₁₆ CuPc), and derivatives thereof.

In some embodiments, the one or more electronically conductive materials are selected from the group consisting of subphthalocyanine, subnaphthalocyanine, dipyrin complexes such as zinc dipyrrhin complexes and BODIPY complexes, perylene, naphthalene, fullerene and fullerene derivatives such as PCBM, ICBA, ) And polymers containing polymers such as carbonyl-substituted polythiophenes, cyano-substituted polythiophenes, polyphenylene vinylenes or electron-deficient monomers such as perylene diimide, benzo-thiadiazole or fullerene &Lt; / RTI &gt; polymers. But are not limited to C ₆₀ , C ₇₀ , C ₇₆ , C ₈₂ , C ₈₄ or derivatives thereof such as phenyl-C ₆₁ -butyric acid-methyl ester ([60] PCBM), phenyl-C ₇₁ -butyric acid-methyl ester ([70] PCBM), or thienyl-C ₆₁ -butyric acid-methyl ester ([60] ThCBM), and other receptors such as 3,4,9,10-perylenetetracarboxylic-bisbenzimidazole PTCBI), hexanedecafluorophthalocyanine (F ₁₆ CuPc), and derivatives thereof.

In some embodiments, the at least one receptor material comprises a material selected from fullerene and a functionalized fullerene derivative. In some embodiments, the at least one electron conductive material comprises a material selected from fullerene and a functionalized fullerene derivative.

Fullerene is of particular interest for use as one or more electronically conductive materials. For example, C ₆₀ is due to the fact that the peaks at 260 nm and 340 nm wavelengths are allowed to transition to the Frenkel type (i.e., monomolecular) state by allowing electron transfer, while the absorption at longer wavelengths is due to the anti- Which is dominated by the two characteristics of the absorption spectrum. At the transition from solution to solid state, for example, C ₆₀ is? = 400 due to the emergence of an intermolecular charge transfer (CT) state resulting from the excitation of electrons from the nearest neighbor LUMO from the HOMO of one fullerene The absorption between 550 nm and 550 nm is significantly increased. When C ₆₀ is mixed with a wide energy gap material on the cathode side, such as BCP, the CT state absorption decreases more rapidly than the Frenkel type characteristic. Thus, when mixed with a wide energy gap material on the cathode side, the fullerene is not added to the device in order not to generate excitons among the fullerene electron conductive materials (even at a moderate dilution rate, e.g., 70% C ₆₀ And even 30% wide gap materials). &Lt; / RTI &gt;

In some embodiments, the at least one electron conductive material comprises a material selected from C ₆₀ and C ₇₀ .

In some embodiments, the at least one receptor material and the at least one electron conductive material comprise the same material. In certain embodiments, the same material is fullerene or a functionalized fullerene derivative. In certain embodiments, the same material is C ₆₀ or C ₇₀ . In some embodiments, the at least one receptor material and the at least one electron conductive material comprise different materials.

In some embodiments, the at least one receptor material and the at least one electron conductive material are selected from different fullerenes and functionalized fullerene derivatives.

In some embodiments, the mixture is mixed in a volume ratio ranging from about 10: 1 to 1:10, such as from about 8: 1 to 1: 8 by volume, from about 6: 1 to 1: To about 1: 4 by volume, or from about 2: 1 to about 1: 2 by volume, and at least one electron-conductive material and at least one wide energy gap material on the cathode side. In certain embodiments, the ratio is about 1: 1. The identified ratios should be understood to include integer and non-integer values.

In some embodiments, donor-receptor heterozygosity is selected from mixed heterozygosity, bulk heterozygosity, planar heterozygosity, and hybrid planar-mixed heterozygosity. In certain embodiments, the donor-receptor heterozygosity is hybrid flat-mixed heterozygosity (PM-HJ). For example, there are two main loss mechanisms in the PM-HJ structure that can reduce FF . One is the bicomponent recombination of the free charge carrier in the broad donor-acceptor blended region of the PM-HJ structure, the rate of which is given by k _BM = &lt; RTI ID = 0.0 &gt; Where γ is the Langevin recombination constant and n (p) is the free electron (hole) density. The second significant loss is due to exciton-polaron quenching in the pure receptor layer. The electron-polaron accumulation observed at the net acceptor / blocking layer interface results in quenching, thereby decreasing the internal quantum efficiency (IQE). Note that both the exciton and polaron concentrations are proportional to the intensity, and that exciton-polaron quenching follows a similar relationship to bi-recombination. Both mechanisms can lose photocurrent under forward bias, which increases the current density-voltage ( JV ) slope feature in the fourth quadrant and ultimately reduces both FF and PCE .

The exciton blocking electronic filter disposed between the photoactive region and the cathode can increase the efficiency of the dual layer OPV cell. The electron conductive material efficiently conducts the electron-polaron, and the wide energy gap material blocks the exciton. Exciton-polaron quenching can be significantly reduced in a bi-layer cell using it due to its ability to spatially separate exciton and polaron from the blocking interface. Finally, V _OC And FF remain unchanged, J _SC can be significantly increased. PM-HJ cells have problems with bis-recombination in further mixed photoactive layers. However, through the filter (mixed layer) of the present disclosure, the interface area with the active layer is reduced due to the increased conductivity of the buffer layer compared to the conventional buffer layer. As a result, the increase in the area between the photosensitive areas makes charge extraction faster. As a result, biomolecule recombination is reduced in the cell.

In some embodiments, the device further comprises at least one additional buffer layer or cap layer disposed between the exciton blocking electronic filter and the cathode. In some embodiments, one or more cap layer has a smaller, smaller LUMO energy level less than 0.2 eV, for example, but rather to within 0.3 eV greater than the LUMO _EC or equal to the, or rather to conduction electrons to the cathode. In certain embodiments, the LUMO energy level of the cap layer is greater than 0.5 eV, such as greater than 0.4 eV, greater than or less than 0.3 eV, or greater than 0.2 eV, than LUMO _EC . In some embodiments, the cap layer has a LUMO energy level of less than or equal to 0.1 eV below the LUMO _EC . In some embodiments, the at least one cap layer is selected from fullerene and functionalized fullerene derivatives. In some embodiments, the at least one cap layer comprises PTCBI.

In some embodiments, the cap layer comprises a material having a LUMO energy level that does not promote the conduction of electrons to the cathode. In this embodiment, the cap layer may be thin enough to transport electrons through the damaged induced state. In some embodiments, the at least one cap layer comprises a material selected from BCP, BPhen, UGH-2, and CBP.

In some embodiments, the at least one cap layer and the at least one electron conductive material comprise the same material. In some embodiments, the one or more cap layers, the one or more electronically conductive materials, and the one or more receptor materials comprise the same material.

In some embodiments, the one or more cap layers and the wide energy gap material on the at least one cathode side comprise the same material.

An exciton blocking hole filter comprises a mixture disposed between the anode and one or more donor materials and comprising at least one wide energy gap material on the anode side and one or more electronically conductive materials. At least one of the wide energy gap materials on the anode side

- greater than HOMO _don , or such a highest occupied molecular orbital energy level (HOMO _AS-WG );

- the lowest unoccupied molecular orbital energy level (LUMO _AS-WG ) that is less than, equal to, or within 0.3 eV of LUMO _don ; And

- it has a large _HOMO-WG -LUMO _{AS AS-WG} energy gap than a HOMO energy gap _don -LUMO _don.

The at least one hole-conducting material has a higher maximum occupied molecular orbital energy level (HOMO _HC ) of less than or equal to (less than) vacuum, equal to, or more than 0.2 eV from (further vacuum) HOMO _don .

In order to extend the operating lifetime of the device by utilizing a morphologically stable material, some embodiments of the present invention may provide a device that is sufficiently high, e.g., higher than the temperature or temperature range at which the device typically operates, A wide energy gap material on the anode side having a glass transition temperature higher than the threshold temperature value or the like is used.

In some embodiments, the HOMO _{AS - WG} is greater than HOMO _don , for example greater than 0.2 eV, greater than 0.3 eV greater, greater than 0.5 eV greater, greater than 1 eV greater, greater than 1.5 eV greater LUMO _{AS - WG} is smaller than LUMO _don , for example, less than 0.2 eV, less than 0.3 eV, less than 0.5 eV, or less than 1 eV Less than 1.5 eV, or less than 2 eV.

In some embodiments, HOMO _HC is equal to HOMO _don .

In some embodiments, HOMO _HC is less than HOMO _don , e.g., less than 0.5 eV, less than 0.4 eV less, less than 0.3 eV less, or less than 0.2 eV.

In some embodiments, the HOMO _HC is less than, or even greater than, 0.1 eV below the HOMO _don .

In some embodiments, the HOMO _{AS - WG} is greater than HOMO _HC , such as greater than 0.2 eV greater, greater than 0.3 eV greater, greater than 0.5 eV greater, greater than 1 eV greater, greater than 1.5 eV greater Or greater than 2 eV.

In some embodiments, HOMO _{AS - WG} is larger by 0.2 eV than than the HOMO _don or, for example, 0.3 is greater in eV greater than, or 0.5 eV greater than greater to or, or greater to 1 eV greater than, greater than 1.5 eV , Or greater than 2 eV.

In some embodiments, the wide energy gap material at one or more anode sides is a tetraaryl-benzidine, such as N, N'-diphenyl-N, N'-bis {1-naphthyl) (TPD), triarylamine, 5,10-disubstituted anthracene (NPD) and N, N'-bis- (3-methylphenyl) -N, N'- , Oligothiophenes, 9,9-dialkyl-fluorenes and oligomers thereof, 9,9-diaryl-fluorenes and oligomers thereof, oligophenylene, spiro-biphenyl and substituted derivatives thereof, and derivatives thereof &Lt; / RTI &gt;

The operational lifetime of the device can be broadened by, for example, a sufficiently wide T _g on the anode side, such as higher than the temperature or temperature range at which the device normally operates, higher than the maximum operating temperature of the device, Can be increased by using an energy gap material. For example, in some embodiments, the wide energy gap material at one or more anode side is selected from the group consisting of 3,3 ', 5,5'-tetra [(m-pyridyl) (1-phenyl-1-H-benzimidazole) (TPBi), bis (2-methyl-8-quinolinol Tris (8-hydroxy-quinolinato) aluminum (Alq3), tris (2,4,6-trimethyl-3- (pyridin- Phenyl) borane (3TPYMB), 4,40- (1,3-phenylene) bis (2,6-diphenylpyridine-3,5-dicarbonitrile) (M-PhPyCN), 4,40- (1,3-phenylene) bis (2,6-di (biphenyl-4-yl) pyridine-3,5-dicarbonitrile (2,6-diphenylpyridine-3,5-dicarbonitrile) (m-PyCN), 6,60- (1,4-phenylene) (p-PPtNN), 4,40- (1,4-phenylene) bis (2-phenyl-6-p-tolylnicotinonitrile) (p- PPtNT), tris (6-fluoro-8- -Quinolinato) aluminum (6FAlq3), 2,6-bis (4- 4,5-dicarbonitrile (CNPyCN), 4,40- (1,4-phenylene) bis (2,6-diphenylpyridine- (p-MPyCN), bisbenzimidazo [2,1-a: 1 ', 2-b'] anthra [2,1,9-def: 6,5,10- 5,10,15-tribenzyl-5H-diindolo [3,2-a: 3 ', 2'-c] carbazole (TBDI), 5,10 (3,5-di (pyridin-3-yl) -1H-pyrazolo [3,4-d] pyrimidin- Phenyl] benzene (BmPyPhB), 1,3,5-tri (m-pyridin-3-ylphenyl) benzene, 1,3,5- (TmPyPB), 9,9-dimethyl-benzo [b] thiophene-3,3'- (MCBP), 3,3-di (9H-carbazol-9-yl) biphenyl (mCBP) , 4,40-bis (triphenylsilyl) -biphenyl (BSB), and derivatives thereof.

In some embodiments, the glass transition temperature of a wide energy gap material on the anode side is greater than or equal to 85 ° C, greater than or equal to 95 ° C, greater than or equal to 105 ° C, greater than or equal to 115 ° C, greater than or equal to 125 ° C, greater than or equal to 135 ° C, At least 175 占 폚, at least 185 占 폚, at least 195 占 폚, at least 200 占 폚, at least 225 占 폚, or at least 250 占 폚.

In some embodiments, the glass transition temperature of the wide energy gap material on the anode side is 85-200 DEG C, such as 90-195 DEG C, 95-190 DEG C, 100-185 DEG C, 105-180 DEG C, 110-175 DEG C, 170 ° C, or 120-165 ° C. It is noted that materials having a glass transition temperature of greater than 200 ° C, such as 200-300 ° C, 200-275 ° C, 200-250 ° C, or 200-225 ° C, may be used.

The operating temperature of the device can be varied and can be varied by a number of factors such as ambient conditions (e.g., temperature, light intensity, etc.) and a reinforcement mechanism (e.g., Depending on whether it is used or not. By way of example, the ambient temperature may vary depending on the geographic location of the device, the year of the year, the day of the week, and so on. Likewise, light intensity may also depend on cloudiness, angle of incidence and other factors, as well as geographical location, year-round time, and daylight time. Thus, in some embodiments, the wide energy gap material on the anode side can be used for a device under a general ambient condition, etc., for example, above a temperature or temperature range that the device typically operates (e.g., under normal ambient conditions) Has a sufficiently high T _g that is higher than the maximum operating temperature.

In some embodiments, the solar thermal concentrator may be integrated into or coupled to the device to increase, magnify, or otherwise increase the light applied to the device. The use of a light concentrator and / or other reinforcement may increase the operating temperature of the device beyond that occurring in the device under normal ambient conditions. Thus, in order to increase the stability and operating life of the device, the wide energy gap material on the anode side may have a higher T _g than the highest operating temperature occurring in the device under increased illumination conditions.

In some embodiments, the one or more donor materials are selected from the group consisting of phthalocyanines such as copper phthalocyanine (CuPc), chloroaluminum phthalocyanine (ClAlPc), tin phthalocyanine (SnPc), zinc phthalocyanine (ZnPc), and other modified phthalocyanines, (3-hexylthiophene) (P3HT), a low band gap polymer, a polyacene, a polyphenylene sulfide, a polyphenylene sulfide, a polyphenylene sulfide, For example, a material selected from pentacene and tetracene, diindenylperylene (DIP), squalene (SQ) dye, tetraphenyldibenzopiperflanthene (DBP), and derivatives thereof. Examples of squalene donor materials include 2,4-bis [4- (N, N-dipropylamino) -2,8-dihydroxyphenyl] squalaine, 2,4- N, N-diphenylamino) -2,6-dihydroxyphenyl] squalaine, 2,4-bis [4- (DPSQ). &Lt; / RTI &gt;

In some embodiments, the at least one hole-conducting material is selected from the group consisting of phthalocyanines such as copper phthalocyanine (CuPc), chloroaluminum phthalocyanine (ClAlPc), tin phthalocyanine (SnPc), zinc phthalocyanine (ZnPc), and other modified phthalocyanines, , Boron subphthalocyanine (SubPc), naphthalocyanine, merocyanine dyes, boron-dipyrromethene (BODIPY) dyes, thiophenes such as poly (3hexylthiophene) (P3HT), low band gap polymer, polyacene Such as pentacene and a material selected from tetracene, diindenylperylene (DIP), squalane (SQ) dye, tetraphenyldibenzopiperflanthene (DBP), and derivatives thereof. Examples of squalene donor materials include 2,4-bis [4- (N, N-dipropylamino) -2,6-dihydroxyphenyl] squalaine, 2,4- N, N-diphenylamino) -2,6-dihydroxyphenyl] squalaine, 2,4-bis [4- (DPSQ). &Lt; / RTI &gt;

In some embodiments, the at least one donor material and at least one hole-conducting material comprise the same material. In some embodiments, the one or more donor materials and the at least one hole-conducting material comprise different materials.

In some embodiments, the mixture is mixed in a volume ratio ranging from about 10: 1 to 1:10, such as from about 8: 1 to 1: 8 by volume, from about 6: 1 to 1: At least one anode-side wide energy gap material and at least one hole-transporting material in a volume ratio of 1: 1 to 1: 4, or in a volume ratio of about 2: 1 to 1: 2. In certain embodiments, the ratio is about 1: 1. The identified ratios should be understood to include integer and non-integer values.

In some embodiments, the device further comprises at least one additional buffer layer or cap layer disposed between the exciton blocking hole filter and the anode.

The organosensitive optoelectronic devices disclosed herein can be grown on, or placed on, any substrate that provides the desired properties. Thus, in some embodiments, the device further comprises. For example, the substrate may be flexible or rigid, planar or non-planar. The substrate may be transparent, translucent or opaque. The substrate may be reflective. Plastics, glass, metals, and quartz are examples of rigid substrate materials. Plastic and metal foil and thin glass are examples of flexible substrate materials. The material and thickness of the substrate can be selected to obtain the desired structure and optical properties.

The organosensitive optoelectronic devices of the present disclosure may serve as, for example, PV devices, such as solar cells, photodetectors, or photoconductors.

Whenever the organosensitive optoelectronic device described herein functions as a PV device, the material used in the photoconductive organic layer and its thickness can be selected, for example, to optimize the external quantum efficiency of the device. For example, an appropriate thickness may be selected to achieve the desired optical spacing in the device and / or to reduce the resistance in the device. Whenever the organosensitive optoelectronic device described herein acts as a photodetector or photoconductor, the material used in the photoconductive organic layer and its thickness may be selected, for example, to maximize the sensitivity of the device to the desired spectral region .

Additionally, the device may further include one or more smoothing layers. The smoothing layer may be located, for example, between the photoactive layer and one or both of the electrodes. 3,4 Polyethylene dioxythiophene: A film comprising polystyrene sulfonate (PEDOT: PSS) is an example of a smoothing layer.

The organosensitive optoelectronic devices of the present disclosure may exist as a stacked device comprising two or more sub-cells. As used herein, a subcell refers to a component of a device comprising at least one donor-acceptor heterologous junction. When a sub-cell is used individually as a photosensitive optoelectronic device, it typically comprises a complete set of electrodes. The stacked device may include a charge transfer material, electrode, or charge recombination material or tunnel junction between the stacked donor-acceptor heterojunction. In some stacked structures, adjacent sub-cells may use a common, shared, electrode, charge transfer region or charge recombination zone. In other cases, adjacent sub-cells do not share a common electrode or charge transfer area. The sub-cells may be electrically connected in parallel or in series.

In some embodiments, charge transfer layers or charge recombination layers are Al, Ag, Au, MoO _3, Li, LiF, Sn, Ti, WO3, indium tin oxide (ITO), tin oxide (TO), gallium indium tin oxide ( GITO), zinc oxide (ZO), or zinc indium tin oxide (ZITO). In another embodiment, the charge transport layer or charge recombination layer may comprise metal nanoclusters, nanoparticles, or nanorods.

In another embodiment, a device of the present disclosure may comprise an exciton blocking charge carrier filter as described herein disposed between a first sub-cell and a second sub-cell, comprising two or more sub-cells. For example, a schematic of the stacked-layer type organic photosensitive optoelectronic devices of the present disclosure is shown in Fig. The electrode 110 includes an anode or a cathode. When the electrode 110 includes a cathode, the electrode 140 is an anode. If the electrode 110 comprises an anode, the electrode 140 comprises a cathode. The stacked device includes two photoactive regions 150 and 160 . Each of these regions may comprise a donor and acceptor organic material to form a donor-acceptor heterologous junction as described herein.

In the device A of FIG. 29 , the layer 115 may be an exciton blocking electronic filter as described herein. In some embodiments, layer 115 may be an exciton blocking hole filter as described herein. A layer 115 is disposed between the photoactive regions 150 and 160 of the sub-cell. In another embodiment, as illustrated by device B of FIG. 29 , the stacked device may comprise a further exciton blocking charge carrier filter. For example, a stacked photosensitive device may include two charge carrier filters disposed between sub-cells. In this structure, if the exciton blocking charge filter 115 is an exciton blocking electron filter, then the exciton blocking charge filter 135 is an exciton blocking electron filter, and vice versa. The stacked device further includes an exciton blocking charge carrier filter disposed between the photoactive region and the electrode, for example, between the photoactive region 150 and the electrode 140 .

Although not shown in FIG. 29 , devices A and B may further include additional separation layers disposed between the sub-cells. The separation layer may comprise at least one electrode, at least one charge transport layer, or at least one charge recombination layer. For example, in device A , the isolation layer is formed by exciton blocking charge filter 115 May be disposed between photoactive region 150 or photoactive region 160 , which is occasionally adjacent to exciton blocking charge filter 115 . In some embodiments, the isolation layer is a charge recombination layer as is known in the art or as described herein.

As a further example, in device B , a separate layer may be disposed between the exciton blocking charge filter 115 and the exciton blocking charge filter 135 , which in some cases may be disposed on one or both of the layers 115 and 135 . In some embodiments, the isolation layer is a charge recombination layer as is known in the art or as described herein.

For example in device A of FIG. 29, if the electrode 110 is disposed between the electron recombination layer is a layer 115 and a photoactive region 150 in the case of a cathode layer 115 and block excitons , And an exciton blocking hole filter that conducts holes from the photoactive region 160 to the charge recombination layer.

Alternatively, in the same structure, where electrode 110 is the anode, layer 115 may be an exciton blocking electronic filter that cuts off the excitons and conducts electrons from photoactive region 160 to the charge recombination layer .

Stacked device may also include two or more exciton blocking charge filter is disposed between the sub-cell as shown in the device B of Fig. If the charge recombination layer is disposed between the layers 115 and 135 in the case where the electrode 110 comprises a cathode, the layer 135 blocks the excitons and conducts holes from the photoactive region 160 to the charge recombination layer Which is an exciton blocking hole filter. The layer 115 may be an exciton blocking electronic filter that blocks the excitons and conducts electrons from the photoactive region 150 to the electron recombination layer.

Alternatively, in the same structure, where the electrode 110 is the anode, the layer 135 may be an exciton blocking electronic filter that cuts off the excitons and conducts electrons from the photoactive region 160 to the charge recombination layer . Layer 115 may be an exciton blocking hole filter that excites the excitons and conducts holes from the photoactive region 150 to the charge recombination layer.

An advantage of the present disclosure is that the exciton blocking charge carrier filter can be transparent because they utilize a wide energy gap material. By mixing a transparent wide energy gap material with an electron or hole conduction material, the electron or hole conduction material can be efficiently diluted and the exciton blocking charge carrier filter can be transmitted at the relevant wavelength. The exciton blocking charge carrier filter is referred to as being "transparent" if it is allowed to transmit at least 50% of incident electromagnetic radiation at the wavelength of interest therethrough. In some embodiments, the filter allows at least 60%, at least 70%, at least 80%, at least 90%, or at least about 100% incident electromagnetic radiation at the wavelength of interest to be transmitted therethrough. A charge carrier filter is said to be optically lossless when it absorbs very small (< 1%) electromagnetic radiation at the wavelength of interest.

In various embodiments, the device preferably utilizes one or more buffer layers that are transparent over the visible light spectrum. A buffer layer for collecting and transporting charge may be present, for example, between the photoactive region and the corresponding electrode. Also, a buffer layer that collects and transports charge may be disposed, for example, between the isolation layer and the photoactive region. In certain embodiments, the layer collecting and transporting charge comprises a material selected from metal oxides. In certain embodiments, the metal oxide is selected from MoO ₃ , V ₂ O ₅ , ZnO, and TiO ₂ .

The layers and materials may be deposited using techniques known in the art. For example, the layers and materials may be deposited or co-deposited from solutions, vapors, or a combination of both. In some embodiments, the organic material or organic layer is deposited or otherwise deposited, for example, by a solution treatment process by one or more techniques selected from spin coating, spin casting, spray coating, dip coating, doctor blading, ink jet printing, Can be co-deposited.

In another embodiment, the organic material may be deposited or co-deposited using vacuum deposition, such as vacuum thermal deposition, organic vapor deposition, or organic vapor jet printing.

Exciton blocking charge carrier filters of the present disclosure, including material mixtures, can be fabricated by varying the deposition conditions. For example, the concentration of each substance in the mixture can be controlled by varying the deposition rate of each substance.

It should be understood that the embodiments described herein can be used with a wide variety of structures. Functional organic photovoltaic devices can be achieved by combining the various layers described in various ways, or the layers can be completely omitted based on design, performance, and cost factors. Additional layers not specifically described may also be included. Other materials than those specifically mentioned can be used. The nomenclature presented for the various layers herein is not intended to be strictly limiting.

It is to be understood that all numerical values expressing quantities of ingredients, reaction conditions, analytical measurements, etc., used in the specification and claims, other than in this embodiment, or otherwise, are to be construed in all cases by the term "about". Accordingly, unless indicated to the contrary, the numerical parameters set forth in this specification and the appended claims are approximations that may vary depending upon the desired properties desired to be achieved by this disclosure. At the very least, and notwithstanding any attempt to limit the application of the doctrine of equivalents to the scope of the claims, each numerical parameter should be construed in light of the number of significant figures and the general rounding approach.

Although numerical ranges and parameters describing the broad scope of the present disclosure are approximations, the numerical values described in this specific embodiment are recorded as precisely as possible unless otherwise specified. However, any numerical value inevitably includes a certain error that is produced from the standard deviation found in each test measurement value.

The devices and methods described herein will be further described by the following non-limiting examples, which are intended to be purely exemplary.

Example

Example 1

C ₆₀ and batocuproin (BCP) were mixed at various concentrations to form an exciton blocking electronic filter. BCP is a broad energy gap material with a single term (3.17 eV) and triplet (2.62 eV) energy higher than C ₆₀ (1.86 eV singlet, 1.55 eV triplet) and LUMO (-1.6 eV) To form an inert dopant, and to prevent energy and electron transfer from C ₆₀ . The doped C ₆₀ : BCP film still blocks the conducting electrons, effectively blocking the excitons. Based on these properties, the doped film was applied as a buffer layer / filter to obtain improved device performance as compared to devices with other buffers.

(x는 C₆₀ 부피 분율이다)으로 피팅되었다. 이는 CT 엑시톤 형성이 2-3개의 분자를 포함한다는 것을 암시하였다. C₆₀:BCP 필름의 흡수 스펙트럼은 도핑 농도가 CT 엑시톤에 대하여 유의적으로 효과를 미쳤고, 심지어 소규모의 도핑 수준에서도 그의 형성을 억제시켰다는 것을 나타내었다.The effect of BCP doping on fullerene absorption was investigated by preparing C ₆₀ : BCP films in various volume ratios. Absorption spectrum of the pure and doped with C ₆₀ films is shown in Fig. As the C ₆₀ fraction decreases, the absorption decreases and reaches the value of BCP. However, the attenuation in each of the Kel-friendly and two charge transfer absorption at 340 nm and 450 nm corresponding to the (CT) exciton peak adopted a very different rates as shown in sapdo of Fig. The extinction coefficient of the frenkel transition allowed at 340 nm was fitted with a linear attenuation according to the C ₆₀ fraction as predicted by Beer's law, which reflects the unimolecular nature of the transition. Interestingly, the extinction coefficient of intermolecular CT absorption at 450 nm showed an exponential decay,

(x is a C ₆₀ volume fraction). This implies that CT exciton formation involves 2-3 molecules. The absorption spectra of the C ₆₀ : BCP films showed that the doping concentration was significantly effective on the CT excitons and even inhibited its formation even at small doping levels.

Example 2

The device was fabricated as follows: Glass substrate coated with patterned ITO (patterned strip width = 2 mm, thickness = 150 ± 10 nm; sheet resistance = 20 ± 5 Ω cm-2; 84%; Courtesy of Thin Film Devices, Inc.) were soap rinsed and boiled in tetrachlorethylene, acetone and propanol (5 min each). The ITO substrate was exposed to ozone atmosphere (UVOCS T10X10 / OES) for 10 min just prior to loading in a high vacuum chamber. The deposition rate for the pure material layer was as follows: MoO _x (0.02 nm / s), NPD (0.1 nm / s), C ₆₀ (0.1 nm / s), BCP / s). The deposition rates for the doped film (C ₆₀ : BCP volume content) were as follows: C ₆₀ : BCP (2: 1) - Co-deposition C ₆₀ (0.08 nm / s): BCP (0.04 nm / s); C ₆₀ : BCP (1: 1) - Co-deposition C ₆₀ (0.06 nm / s): BCP (0.06 nm / s); C ₆₀ : BCP (1: 2) - Co-deposition C ₆₀ (0.04 nm / s): BCP (0.08 nm / s). After the organic deposits, place the mask in a strip width of 2 mm on the substrate under N _2, and Al cathode was deposited in 100 nm. The device area was 4 mm 2.

In order to observe the clear optical reaction from C _60, also having a structure as shown in Figure 3, a large gap, a hole transport material as a donor N, N'- di - [(1-naphthyl) - N, N '- Diphenyl] -1,1'-biphenyl) -4,4'-diamine (NPD). The net layer of C _{60 at} the D / A interface was intended to preserve the thermodynamic properties and dynamic properties of charge separation so that all changes observed between devices could be related to the bulk of the doped film instead of the interfacial effect.

In simulated AM 1.5G jomyeongha current of 1 sun intensity of the device (100 mW / ㎠) - voltage (JV) characteristics and the external quantum efficiency (EQE) curves are shown in Fig. As shown in the following Table 1 , the short-circuit current ( J _SC ) was 1.3 ± 0.1 mA / cm 2 at 3.0 ± 0.1 mA / cm 2 as the doping concentration of the C ₆₀ : BCP layer was increased from 1: By 1.7 mA / cm &lt; 2 &gt;. The reduction was to, as reflected in the EQE measurements, due to C ₆₀ photoreaction drop, on the other hand, the open circuit (V _OC) is substantially been maintained unchanged as 0.87 ± 0.01, fill factor (FF) is a C ₆₀ As the fraction decreased, it increased from 0.45 ± 0.01 to 0.49 ± 0.01. The decline in the EQE response correlated well with the absorption profile of the doped C ₆₀ film, where the reduction in response between 400 nm and 550 nm occurred faster than at wavelengths shorter than 400 nm. The effect of CT excitons can be most clearly seen by comparing D1 and D2. In the device, the EQE response at 350 nm remained unchanged while the EQE response at 450 nm decreased from 23% to 15.5%, approximately one-third.

Observations of the photoreaction reduction with increasing doping concentration of BCP in the mixed layer show that the photocurrent is significantly increased when the SubPc is diluted with the broad energy gap material UGH2 [Menke et al., J. Nat . Mater. 2012]. For SubPc, (Menke) proved that the photocurrent increase is due to the increased exciton diffusion length caused by the fact that the Forster radius increased faster than the average molecular separation distance. The increase in diffusion distance was attributed to the photoluminescence efficiency in the doped film, the excited state lifetime, and the increase in spectral superposition integral, and the decrease in the non-radiative decay rate. The contrast between the results can be explained by examining the ratio (%) of the excitons involved in the two systems. Unipole posterite exciton was formed in SubPc. During dilution, the absorption loss was linear, whereas the exciton diffusion distance acquisition was exponential. Conversely, a considerable number of multimolecular CT excitons were formed at C ₆₀ . During dilution, this resulted in exponential decay of CT exciton formation, which exceeded any diffusion distance acquisition. The overall performance of the device has been reduced due to the fact that CT absorption characteristics at C ₆₀ are caused by regions of high irradiation.

When the mixed device had a lower photocurrent, the V _OC of the device remained unchanged, suggesting that D / A interface preservation achieved its desired effect. The fact that FF did not decrease during C ₆₀ dilution indicated that the mixed film was able to efficiently transport the electrons. The unmodified V _OC and FF increase, combined with J _SC increase, reduced the power conversion efficiency (η) at dilution from 1.14% (D1) to 0.56% (D4) by more than 50%. However, with the increased transparency of the mixed film and efficient charge transport, the C ₆₀ : BCP film becomes a candidate material of interest as a buffer layer.

Example 3

The device shown in Fig. 4 was fabricated according to the manufacturing method disclosed in Example 2. Fig . Figure 4 shows a plot of external quantum efficiency as a function of the JV curve and wavelength of a device under 1 sun AM 1.5G illumination where the device structure is shown (x = 10 nm (D7), 20 nm (D6), 30 nm (D5)). Table 2 below provides performance data for the device.

Example  4

The device shown in Fig. 5 was fabricated according to the manufacturing method disclosed in Example 2. Fig . Figure 5 shows a plot of external quantum efficiency as a function of the JV curve and wavelength of a device under 1 sun AM 1.5G illumination where the device structure is shown (x = 0 nm (D8), 20 nm (D9), and 40 nm (D10)). Table 3 below provides performance data for the device.

Example 5

An OPV device as shown in Fig. 6 (bottom illustration) was fabricated. Two C ₆₀ layers (one (1), one (2), and one (2)) were formed using a red absorbing donor (2,4-bis [4- (N, N-diphenylamino) -2,6-dihydroxyphenyl] squaraine Of the BCP: C ₆₀ layer with a thickness of 10 nm and a thickness of 35 nm and a thickness of the other one of 40 nm- x ). The total thickness of the pure C ₆₀ and BCP: C ₆₀ films was 50 nm. Figure 6 shows the JV and EQE characteristics of devices D20-D23 (x = 5 nm to 35 nm and other performance parameters are shown in Table 4 below). BCP: As the C ₆₀ layer migrated toward the D / A interface (ie, as x decreased), J _SC decreased from 6.2 ± 0.3 mA / cm 2 to 4.1 ± 0.2 mA / cm 2. This tendency was also apparent in the EQE spectra where the reaction from C ₆₀ was reduced as the thickness of the net C ₆₀ layer adjacent to the D / A interface decreased (D20 to D23 in Table 4 ). The data suggested that BCP: C ₆₀ prevents the excitons generated in the C ₆₀ film adjacent to the metal electrode from diffusing to the D / A interface where dissociation into free charge may occur. In contrast, as can be deduced from constant and high FF = 0.72 + 0.01 and V _OC = 0.94 + 0.01 V, the mixed layer does not interfere with charge transport. The power conversion efficiency under 1 sun AM 1.5G illumination increased from 2.7 ± 0.1% to 4.1 ± 0.1% when the thickness of the C ₆₀ layer adjacent to the D / A interface was increased from x = 5 nm to 35 nm.

Example  6

The device shown in Fig. 7 was fabricated according to the fabrication method disclosed in Example 2. Fig . FIG. 7 shows the JV curve of a device under 1 sun AM 1.5G illumination (where the illustration shows the characteristics of the device) and external quantum efficiency as a function of wavelength (where the illustration shows the device structure). The device compared the performance of the mixed buffer layer capped with additional layers to enhance the charge collection with that of a single pure PTCBI buffer layer.

Example 7

The device shown in Fig. 8 was fabricated according to the fabrication method disclosed in Example 2. Fig . Figure 8 shows the external quantum efficiency under the applied bias (+0.5 V dashed line, -1 V solid line) for various buffer layers normalized to EQE at zero bias. The data demonstrated that the mixed buffer layer reduced the dependence of the bias of the device, which illustrates a reduction in the charge accumulation on the active layer / buffer interface and consequently a reduction in the amount of exciton-polaron quenching.

Example 8

The mechanism by which the mixed layer intercepts the excitons can be viewed in a statistical manner, in which case the reduction in density of the states available in the doped layer reduces the exciton transfer rate. In the mixed layer, the number of states in which energy can be transferred is significantly reduced while effectively blocking its progress. Effect of density change of state has been modeled by a Monte Carlo, and the results can be seen in Fig. In the model, excitons were randomly generated in the pure film adjacent to the mixed film. Then, to simulate the diffusion, the exciton moved to a predetermined number of steps through a random walk and then recorded its final position. The excitons are assumed to be delivered only by nearest neighbor hopping. At the interface between the doped layer and the net layer, the probability of hopping between layers was scaled by the relative number of available sites in each layer. The model predicted that for junctions between two materials of the same site density, 50% of the excitons were diffused into the buffer. In the case of a 50% reduction in the portion of the buffer corresponding to the case of a C ₆₀ frenchal exciton near 1: 1 C ₆₀ : BCP buffer, only 20% of the exciton was delivered. Less than 5% of the excitons were delivered at 80% site reduction, simulating a CT exciton case close to 1: 1 C ₆₀ : BCP buffer. This simulation demonstrated that the doped buffer blocked excitons very well even when considered only as statistical means.

Example 9

As shown in FIG. 10 , the normalized extinction spectrum of C ₇₀ capped with different buffer layers was plotted as a function of wavelength in the top graph. The data demonstrate that the more the exciton energy is mixed, the lighter it is, and that it has helped to block excitons. The chart at the bottom is Quinging (NPD). (BCP), and an emission spectrum of C ₇₀ (excited at 450 nm), capped with a mixed buffer layer.

Example 10

As shown in FIG. 11 , the EQE spectrum (top) of the device capped with various buffer layers and the JV curve (bottom) of the device under 0.8 sun AM 1.5G illumination are due to containing compound buffer as compared to other buffer layers And the performance is improved.

Example 11

The use of a buffer composed of C ₆₀ : BCP was analyzed and its performance compared to that of the buffer buffer previously developed, BCP and PTCBI, and C ₆₀ : BCP capped with BCP or PTCBI. In the device, the active layer was composed of DPSQ / C ₆₀ . JV, EQE, and device structure are shown in FIG. 12 , and related data is shown in Table 5 below. The V _OC of the device remained constant at 0.95 ± 0.01 V regardless of the buffer. The device capped with 10 nm PTCBI buffer (D13) exhibited the smallest J _SC of 7.1 ± 0.1 mA / cm 2 due to parasitic optical absorption from PTCBI. Unlike the ²⁰ PTCBI, the other buffer BCP (D11), and C ₆₀ having a thickness of 10 nm: did not absorb the BCP (D12), as a result, J _SC is a 7.5 ± 0.1 mA / ㎠ and 7.6 ± 0.1 mA / ㎠ each Respectively. The compound buffer layer with a thickness of 15 nm, C ₆₀ : BCP / PTCBI (D14) and C ₆₀ : BCP / BCP (D15) had a much higher J _SC of 8.1 ± 0.1 mA / cm 2 and 8.3 ± 0.1 mA / Respectively. EQE measurements demonstrated that the increase in photocurrent was due to the C ₆₀ response variation and that the increase in J _SC during transition from 10 nm to 15 nm of the buffer through optical modeling ⁹ using transfer matrix formalism was due to optical effects . Significant changes also occurred in FF between devices. The BCP capped devices D11 and D15 exhibited the smallest FF of 0.64 ± 0.01 and 0.65 ± 0.01, respectively. The buffer (D12) consisting solely of C ₆₀ : BCP had slightly better FF at 0.66 ± 0.01. The devices D13 and D14, which were capped with PTCBI, showed the largest FF of 0.68 ± 0.01 and 0.71 ± 0.01, respectively. For if BCP is, 4.8 ± 0.1%, PTCBI, : due to the photoelectric current and FF increases, C _60: BCP / power conversion efficiency of PTCBI buffering agents are C _60: If the BCP / BCP, 5.0 ± 0.1% , C 60 4.8 ± 0.0 = 1%, and 5.3 ± 0.1% compared to 4.8 ± 0.1% for BCP.

The FF difference between the buffer layers could be explained by examining the EQE under the applied bias and the reactivity (R) as a function of roughness. Figure 13 shows EQE for a device with various buffer layers under -1 V bias normalized to 0 V EQE. The signal from C ₆₀ at 400 to 550 nm was modulated by application of an external bias while the DPSQ reaction between 600 nm and 825 nm remained constant. The effect of the buffer layer was found by the magnitude of deviation from zero bias EQE. The voltage dependence was most significant for the device capped with a buffer of 10 nm BCP (D11), but the smallest for the 10 nm C ₆₀ : BCP buffer (D12).

The device (D15) capped with 10 nm C ₆₀ : BCP / 5 nm BCP had a lower voltage dependence than the 10 nm BCP (D11). This was due to two factors. First, because the BCP layer is thinner, the number of trapped electrons is reduced. Second, as indicated above, the C ₆₀ : BCP layer still prevented the electrons from being transported while the exciton was diffused to the C ₆₀ : BCP / BCP interface. This prevented the excitons from interacting with the trapped electrons at the C ₆₀ : BCP / BCP interface.

Due to his LUMO alignment through the 10 nm PTCBI (D13) buffer he was able to achieve isobaric transport from C ₆₀ . At the same time, the PTCBI / Ag interface did not form any dipole or energy barrier for charge extraction. 10 nm C ₆₀ : BCP / 5 nm PTCBI (D14) acted in a similar manner, preventing the excitons from reaching PTCBI.

The polaron-exciton induced exciton quenching was further demonstrated by investigating the reactivity as a function of the illuminance presented in FIG. The reactivity is defined as the value of the short-circuit current density of the device divided by the incident surface luminous intensity. Through the above parameters, the inventors have been able to compare the current generation efficiency of devices under various illumination intensities. The BCP-capped devices D11 and D15 showed a markedly nonlinear response with increasing illumination from 1 W / m2 (0.01 sun) to 100 W / m2 (1 sun). Nonlinear damping properties were consistent with increased exciton-polaron induced exciton quenching in both the exciton and polaron groups with increasing illumination. All of the other buffers used in D12, D13, and D14 showed a small change in reactivity as a function of roughness, demonstrating that exciton-polaron induced exciton quenching was inhibited.

Example 12

C ₆₀ : In order to investigate the exciton blocking property of C ₆₀ , a red absorbing donor (2,4-bis [4- (N, N-diphenylamino) -2,6-dihydroxyphenyl] squalene) (DPSQ) was used to fabricate a device containing a doped C ₆₀ layer sandwiched between two net C ₆₀ layers. ^{20 and 21} ( Fig. 14 ). The total thickness of the pure C ₆₀ and C ₆₀ : BCP films was constant; Only the position of the doped film was shifted toward the Ag electrode at the D / A interface.

The JV and EQE characteristics of device D16-19 are shown in FIG. 14 , and the associated data is shown in Table 6 below. As the thickness of the net C ₆₀ layer adjacent to the D / A interface decreases from 35 nm to 5 nm (or as the C ₆₀ : BCP layer moves toward the D / A interface), the photocurrent of the device is 6.2 ± 0.1 mA / cm 2 To 4.1 ± 0.1 mA / ㎠, respectively. This tendency was also observed in the EQE spectrum where the reaction from C ₆₀ decreased as the thickness of the net C ₆₀ layer adjacent to the D / A interface decreased (D16 to D19). The results clearly demonstrate that C ₆₀ : BCP acts as an exciton blocking layer by effectively blocking excitons generated in the pure C ₆₀ film adjacent to the metal electrode from being diffused to the D / A interface where charges are separated . Unlike its exciton blocking function, the doped layer exhibited excellent charge conductivity as the device's FF was kept constant at 0.72 ± 0.01. V _OC was also maintained at 0.94 + - 0.01. Overall, the eta increased from 2.7 ± 0.1% to 4.1 ± 0.1% as the thickness of the net C ₆₀ layer adjacent to the D / A interface increased from 5 nm to 35 nm.

Example 13

Figure 15 shows a plot of the external quantum efficiency of a device with various buffer layers as a function of the JV curve under 1 sun AM 1.5G illumination at the top and the wavelength at the bottom. Performance enhancements have been demonstrated due to the inclusion of a buffer layer mixed through the device.

Example 14

Figure 16 shows a plot of the external quantum efficiency of a device having various buffer layers containing a JV curve under 1 sun AM 1.5G illumination at the top and various ratios of C ₆₀ versus BCP. The optimal blending volume ratio was proved to be 1: 1 through the device.

Example  15

To prepare a device by using the following structure: glass substrate / 100 nm ITO / 10 nm MoO 3/54 nm 1: 8 DBP: C 70 / buffer / 100 nm Ag. 17 is relatively thick, 1: 8 by volume with DBP and C for a plane mixed OPV cell having an active layer comprising a layer of the net _70, JV (upper left) for the illumination of at 1 sun simulated AM 1.5G one trillion people And EQE (top right) and extracted efficiency parameters (bottom). The thickness and volume ratios of BPhen: C ₇₀ for each buffer are given in the table. In the case of a device comprising a mixed buffer with an additional BPhen or PTCBI layer between the mixed region and the contact, the fill factor and efficiency were the best, demonstrating that the contact also improved the mixed or bulk heterojunction device .

Example 16

To prepare a device by using the following structure: glass substrate / 100 nm ITO / 5 nm MoO 3/25 nm 1: 8 DBP: C 70 / buffer / 100 nm Ag. FIG. 18 is a plot of the JV (%) versus time for illumination in a 0.7 sun simulated AM 1.5G illumination for a planar mixed OPV cell with an active layer comprising a net layer of DBP and C ₇₀ and a variable buffer in a relatively thin 1: Upper left) and EQE (upper right) and extracted efficiency parameters (lower). The thickness and volume ratios of BCP: C ₇₀ for each buffer are given in the table. In the case of a device comprising a mixed buffer with an additional BPhen or PTCBI layer between the mixed region and the contact, the fill factor and efficiency were the best, which also improved the mixed or bulk heterojunction device, Demonstrating that exceptionally good fill factors can be obtained in mixed layer devices.

Example 17

A device was fabricated with the structure identified in Fig . The device of FIG. 19 (a) had an ITO / MoO ₃ / DPSQ / C60 / C ₆₀ : BPhen (x) / BPhen / Al structure. The device of FIG. 19 (b) had an ITO / MoO ₃ / DPSQ / C60 / C ₆₀ : BCP (x) / BPhen / Al structure. The device of FIG. 19 (c) had an ITO / MoO ₃ / DPSQ / C ₆₀ / C ₆₀ : UGH 2 (x) / BPhen / Al structure. Figure 19 shows EQE and JV curves for dilution using BPhen, CBP, and UGH2. Enhancement was observed in all cases and it was confirmed that this was promoted by the reduction of charge accumulation at the C ₆₀ / buffer interface.

Example 18

OPV cells were grown by vacuum thermal deposition (VTE) at a base pressure of 2 * 10 &lt; ^-7 &gt; torr on a glass substrate precoated with indium tin oxide (ITO, sheet resistance: 15 ohms / square). Prior to precipitation, the substrate was cleaned in diluted Tergitol 占 (Type NP-10), deionized water, acetone and isopropyl alcohol and then exposed to ultraviolet ozone for 10 minutes. MoO ₃ is available from Acros Organics, C ₆₀ is from Materials and Electrochemical Research Corp., BPhen and DBP from Luminescence Technology Corp. , and C ₇₀ was obtained from the SES Research (SES Research). DBP, C ₆₀ and C ₇₀ were purified once through thermal gradient sublimation.

The MoO ₃ and BPhen layers were grown at a rate of 0.1 nm / s. DBP and C ₇₀ were co-deposited using a DBP deposition rate of 0.02 nm / s and a C ₇₀ deposition rate of 0.16 nm / s to achieve a 1: . By co-deposition of the respective BPhen and C ₆₀ at a rate of 0.05 nm / s 1: 1 blend by generating BPhen: C ₆₀ Mixed buffer was grown. A 100 nm thick Ag cathode was then deposited through a shadow mast defining an array of 15, 1 mm diameter devices (device area 0.008 cm2). After fabrication, the device was transferred to a glove box filled with ultrahigh purity N ₂ for JV characterization and EQE measurements. During the measurement, only the device being tested was placed under illumination and the other device was kept in the dark room. The NREL trackable Si reference cell was used to calibrate the solar simulator strength and the J _SC corrected for spectral mismatch. EQE was obtained as a function of wavelength ( I ) using monochromated light from a lock-in amplifier and an Xe lamp chopped at 200 Hz. The errors in J _SC and PCE are mainly due to uncertainties in luminance and spectral correction.

HJ cells were grown by vacuum thermal evaporation (VTE) with MoO ₃ (10 nm) / DBP: C ₇₀ (54 nm, 1: 8 volume ratio) / buffer / Ag (100 nm). Two different buffer layers were used: a BPhen: C ₆₀ mixture of 10 nm thick, mixed in a 1: 1 ratio (volume ratio) capped with an 8 nm thick BPhen (control) and a 5 nm thick BPhen layer Layer. Figure 20 shows JV characteristics and EQE spectra of mixed HJ devices using control and compound buffer. The control group has FF = 55 ± 1%, J _SC = 12.5 ± 0.3 mA / cm 2, V _OC = 0.91 ± 0.1 V and PCE = 6.3 ± 0.3% under the simulated AM 1.5G, Coefficient = 1.00 ± 0.01). Compound E-a filter cell containing a buffering agent is improved in all three performance parameters as FF = 63 ± 1%, J SC = 12.8 ± 0.3 mA / ㎠, V OC = 0.93 ± 0.1 V and PCE = 7.5 ± 0.4% And the latter corresponded to a 19% increase compared to the control group.

A significant improvement in FF for a device comprising a compound buffer is shown in Figure 20 (a) ( indicated by the shaded region between the curves), wherein Figure 20 (b) shows an energy level diagram . Previous work has shown that energy level bending occurs at the fullerene / BCP interface, leading to a large potential drop as shown in the electron accumulation and left intemal diagrams. As a result, as the voltage was redistributed, the electric field between the active layers decreased while, at the same time, the charge extraction time increased, thereby prolonging the residence time of electrons and holes at the donor-acceptor heterointerface with the opportunity for its recombination . For a compound buffer, 1: 1 BPhen: C with high conductivity of ₆₀ blend electron accumulation was reduced, thus, the potential drop at the interface is smaller (right sapdo, FIG. 20 (b)), DBP: C 70 mixed Lt; RTI ID = 0.0 &gt; region. &Lt; / RTI &gt; This eventually resulted in a decrease in the birefringence and, as a result, the FF and EQE were increased at I = 400 nm to 550 nm wavelength, as shown in Fig. 20 (b) .

Both cells showed almost the same EQE at I < 400 nm and > 550 nm (see Fig. 20 (b)). At λ <400 nm, the absorption of photoactive regions in compound buffer cells was reduced due to parasitic absorption in BPhen: C ₆₀ mixed buffer, while the internal quantum efficiency ( IQE ) increased due to diminution of bimolecular recombination. Overall, the EQE of the compound buffer cell was nearly identical to that of the control cell. At λ> 550 nm, the excitons generated in the DBP: C ₇₀ mixed region were almost immediately dissociated to charge, so that the charge distribution peak as well as the absorbed light output peak shifted toward the anode. This simultaneously improved the hole extraction while reducing the group of holes in the DBP: C ₇₀ / BPhen interface where electrons were accumulated (close to the cathode side) in the control cell. Spatial separation of holes and electrons at longer excitation wavelengths reduced bisectional recombination in the control cells, which resulted in approximately the same EQE .

To understand the role of bi-recombination, the reactivity (R) for both cells was investigated as a function of luminosity ( I ). When the control cell is I = 0.6 sun at R = 12.7 ± 0.4 A / W from a 11.8 ± 0.3 A / W at I = 2.7 suns, R is the case, while shown to the chancel reduced, compound hwanchung the battery, R fell by only 0.2 A / W over the same intensity range ( see FIG. 21 ). Generally, J _SC = J _G - J _MM - J _BM where J _G is the photogenerated current density, J _MM is the monomolecular recombination current density, and J _BM is the biomaterial recombination current density. J _G and J _MM are both linearly proportional to I , while J _BM αγ · n · pαb · I ² , where γ is the Langebein coefficient and b is a constant. Therefore, R = J _SC / I = R _{0 -} ? 占 (wherein R ₀ is the reaction diagram in the absence of a biomaterial. (Dashed line in FIG . 21 ) R ₀ = 12.9 A / W was obtained for both of the cells through the linear pits for the analysis. The same cut-off for both cells at a light intensity of 0 suggests that the reactivity of both OPV cells was equal to I → 0 under the absence of biomolecular recombination. However, beta for the control group was four times greater than for the cell with compound buffer. The smaller ? For the compound buffer cell suggests that bisectional recombination was only 25% of that of the control cell, which reduced the electron and hole concentration by an average of 50%, respectively, due to the electric field increase in the mixed region Lt; / RTI &gt; As compared to the control for this given external bias, charge extraction improved as the internal electric field between the heterojunctions in the compound buffer cell increased, and FF increased.

The charge transport properties of the compound buffer were further investigated by 3D Monte Carlo simulation of the programmed layer in Matlab. The buffer was modeled by randomly distributing BPhen and C ₆₀ molecules on a cubic lattice, and electron transport was due to nearest neighbor hopping between C ₆₀ molecules. In this model, the Coulomb interaction between charges is neglected, and the lattice site is assumed to be a backlight, in addition to the energy difference imposed by the applied electric field. The transfer probability was calculated according to the Miller-Abrahams theory, from which the median extraction time for charge injected on one side of the buffer layer was obtained. The layer mobility was then calculated from the relationship between the extraction time and the electric field, normalized by setting the mobility of electrons in the zero electric field in the net C ₆₀ layer to the experimental value of 5.1 × 10 ^-2 ㎠ / V · s . For the 1: 1 mixed buffer, the model predicted that the effective mobility was 4.7 × 10 ^-3 ㎠ / V · s , which was only 10 times lower than the net C ₆₀ value. In comparison, the electron mobility of the pure BPhen film was significantly lower at 1.9 × 10 ^-5 cm 2 / V · s , resulting in charge accumulation at the buffer interface, which promoted quenching.

The model was tested by examining the predicted results when the thickness of the 1: 1 mixed buffer was different, and the results are shown in Figure 22 (a) . There is a linear relationship between extraction times (corresponding to film mobility) at a given voltage and thickness of the mixed layer, assuming that the charge density is constant (i.e., when the illumination is constant) Resistance was interpreted to increase linearly. The pit for the experimental data for the mixed buffer DBP: C ₆₀ OPV is shown in FIG. 22 (a) , an explanatory view. Now, the net BPhen layer, which conducts electrons through the defect state, was induced during metal deposition, which induced a superlattice relationship between thickness and resistance. In contrast, the mixed buffer resistance even increased linearly up to a thickness of 20 nm, suggesting that the electrons in the mixed buffer were mostly conducted by C ₆₀ in the mixture.

The exciton blocking efficiency using the photoluminescence (PL) excitation spectrum of a 40 nm thick C ₇₀ film capped with a 1: 1 BPhen: C ₆₀ blend in quartz was experimentally investigated. The relative importance of the process was determined by comparing the PL intensity of the layer deposited on the surface of the blend under study with that of a "perfect" barrier or quench layer. Thus, for this purpose, layers of BPhen or N, N'-diphenyl-N, N'-bis (1-naphthyl) -1-1'biphenyl-4,4'diamine (NPD) As a complete exciton blocking layer or quenching layer. PL intensity of the mixed buffer was almost the same as that observed for the reference block intensity (see Fig. 22 (b)), which BPhen: to demonstrate that C ₆₀ is a mixture layer can be efficiently blocked by the exciton. BPhen: since the electron mobility of the C ₆₀ mixture is relatively high, the mixed buffer layer acts as an effective filter it is possible to spatially separate the exciton and polaron, whereby the exciton in the order of the fullerene layer, the polaron quenched .

Example 19

An OPV cell with a hybrid planar-mixed heterojunction (PM-HJ) was fabricated according to the experiment described in Example 18. The DBP and C ₇₀ were respectively used as the donor and acceptor in OPV cells. The OPV cell had a device structure of indium tin oxide (ITO) / MoO ₃ (10 nm) / DBP: C ₇₀ (54 nm, 1: 8 volume ratio) / C ₇₀ (9 nm) / buffer / Ag (100 nm) . Three different buffer layers were used in the DBP: C ₇₀ PM-HJ OPV cell: (1) 8 nm thick battobotanthanthroline (BPhen) (control); (2) 1: 1, the mixing ratio of 10 nm thick BPhen: C ₆₀ mixed layer; And (3) capped with a 5 nm thick BPhen layer in order.

Figure 23 is a buffer layer structure (1) - (3), and the current density vs. voltage (JV) to compare the performance of the device with the features, and as showing the external quantum efficiency of EQE, the spectrum, the following Table 7 summarizes the proposed .

Control cells had a similar to the previous result, or a little better than FF = 56% and the short-circuit current _{J SC = 13.8 ± 0.4 mA /} ㎠ 1. Thus, the control cell showed a power conversion efficiency of PCE = 7.1 ± 0.2% under simulated AM 1.5G, 1 sun illumination. A cell with only a BPhen: C ₆₀ (1: 1) filter, in comparison to a control cell, had a similar open circuit voltage ( V _OC ) = 0.91 ± 0.01 V as compared to a control cell, - Increased FF = 62 ± 1% due to reduction of exciton quenching ^{2 , 3} . However, as shown in Figure 23 (b), due to the reduced EQE results for λ <420 nm and λ> 550 nm J _SC = 12.8 ± 0.3 mA / cm2 was slightly smaller. Overall, the PCE slightly increased to 7.2 ± 0.2% under 1 sun illumination.

OPV cells with BPhen: C ₆₀ / BPhen compound buffer had FF = 66 ± 1%, which was 18% improved compared to the control. In addition, V _OC was increased from 0.91 ± 0.1 V for the control group to 0.93 ± 0.1 V for the battery with the BPhen: C ₆₀ / BPhen buffer. However, J _SC decreased to 13.2 ± 0.4 mA / ㎠ and decreased by 5% compared with the control group. Overall, OPV cells with BPhen: C ₆₀ / BPhen buffer showed PCE = 8.1 ± 0.4% under simulated AM 1.5G, 1 sun illumination, which was 14% higher than the control cell.

24 , the absorption efficiency ? _A of the organic photoactive region (i.e., the DBP: C ₇₀ mixed layer and the net C ₇₀ capping layer) is calculated using the transfer matrix methods ^{4 and 5} and the internal quantum efficiency (IQE) Respectively. The absorption of the capped buffer cell was reduced at λ = 350 nm to 500 nm due to the absorption of ³ , BPhen: C ₆₀ mixed buffer as described above. At > 500 nm, the mixed buffer was clear, and therefore both cells had approximately the same absorption spectrum.

Similarly, IQE is BPhen: increased from ₆₀ C / BPhen that for the cell having a buffer, λ = 350 nm to 550 nm as compared to the control cells. For example, for a cell with a BPhen: C ₆₀ / BPhen buffer, IQE had ~ 90% EQE at λ = 350 nm to λ = 500 nm and ~100% at λ = 430 nm, Indicating that all of the photons have been converted into charge carriers collected by the electrodes.

The response ( R ) and PCE for BPhen: C ₆₀ / BPhen filtered cell and control as a function of luminosity in the range of 0.4 sun to 2.7 sun were studied ( Figure 25 ). Response of the control cells whereas at 0.4 sun R = 14.9 ± 0.4 A / from W at 2.7 sun to 13.0 ± 0.4 A / W strength is monotonically decreasing, the filtering cell is invariably on the solar concentration of the range, such as the . The control cell also showed a roll-off of the PCE as brightness increased as shown in Figure 25 due to the reduced monotony of reactivity. The PCE of a cell with BPhen: C ₆₀ / BPhen buffer increased slightly to a maximum of 1 sun, and then rolled off at a higher intensity, possibly due to a decrease in FF , which was probably caused by bispecific enhancement at high light .

In addition, the thickness of the buffer layer mixed in the DBP: C ₇₀ PM-HJ battery with the BPhen: C ₆₀ / BPhen buffer was varied. JV characteristics and EQE spectra under 1 sun illumination are shown in FIG. 26 , and device performance is summarized in Table 8 below.

As the thickness of the mixed buffer increased, J _SC decreased monotonically. As shown in Figure 26 (b), as the mixed layer thickness increased, the EQE decreased over the visible spectrum. V _OC slightly increased from 0.91 ± 0.01 V to 0.93 ± 0.01 V for cells with a mixed buffer of 10 nm thickness for cells without a mixed buffer layer and for thicker mixed buffer layers In a safe manner. As shown in Table 8 , due to the increase in series resistance, the FF increased from 0.56 +/- 0.01 for control cells to 0.66 +/- 0.01 V for mixed buffer of 10 nm thickness, followed by a thicker mixed buffer The roll-off was performed.

On the other hand, with the mixed layer modeled as a random distribution of C ₆₀ and BPhen molecules, the charge transport through the mixed buffer layer was modeled using a 3D Monte Carlo simulation of nearest neighbor hopping transport in the cubic lattice. The Coulomb interaction between charges is neglected and the lattice region is assumed to be a backlight, in addition to the energy difference imposed by the applied electric field. The relative hopping probability between sites was calculated according to the Miller-Abrahams equation. During each time step of the model, the charge selected random nearest neighbors weighted by the relative hopping probability for hopping. If the selected site contained a BPhen molecule, the charge was kept stationary during this step instead. Charge behaviors in the mixed and net layers were the same in all other cases.

The median extraction time for different thicknesses was calculated by injecting charge on one side of a 100x100 simulated lattice of the site and measuring the time it takes for the charge to escape from the opposite side under an electric field. Figure 27 shows the extraction time median vs. electric field as a function of mixed layer thickness. For a given thickness of the mixed layer, the electric field accelerated the charge transport in the mixed layer, thereby shortening the extraction time median as the electric field increased. As the mixed buffer thickness increased, it took a longer time for the charge to pass through the mixed layer. Thus, the median extraction time was longer as the mixed layer thickness increased.

To test the predicted results of the model, the series resistance obtained by fitting the JV feature in the darkroom, as shown in Table 8 , was compared to the value obtained from modeling for PM-HJ cells with different mixed layer thicknesses. The mixed layer mobility with different thicknesses was calculated from the electric field dependence of the extraction time and the effective mobility of the simulated layer was found to be 4.7 × 10 ^-3 ㎠ / V · s , where 1 / electric field dependence = extraction It was time. Thus, the resistance layer as set forth in sapdo of Figure 27 that was expected to be about the thickness depends in a linear manner. The predicted mobility of the 1: 1 mixed buffer layer was only 10 times less than the relatively high pure C ₆₀ for organic materials, thereby explaining how the layer could efficiently extract charge into the innermost layer. As suggested in previous simulations, the layer was efficient in blocking the excitons, thereby spatially separating the excitons and polarons to inhibit quenching.

Example 20

The device as shown in Fig . 28 was fabricated as illustrated. The overall structure was glass substrate / ITO (100 nm) / MoO ₃ (100 nm) / Buffer 1 / DBP (20 nm) / C ₆₀ (40 nm) / Buffer 2 / Ag (100 nm) Buffer 2 and the corresponding measured efficiency parameters are shown in Table 9 below. Figure 28 (a) shows the JV for illumination under 1 sun simulated AM 1.5G illumination, where the illustration shows NPD, (b) shows an OPV cell with DBP and C ₆₀ and an active layer composed of various buffers Lt; RTI ID = 0.0 &gt; quantum efficiency. &Lt; / RTI &gt;

The thickness, composition, and efficiency parameter measurements for each filter are shown in Table 9 . Compared with the reference, when the NP layer of NPD was included as a filter, J _SC increased significantly with the decrease of FF. The use of a filter consisting of a 1: 1 blend of DBP with NPD improved the FF when compared to reference devices, while still improving J _SC , compared to using only NPD alone. With the electronic filter at the cathode, the NDP: DBP hole filter increased the PCE by 10%.

Example  21

The device shown in Fig . 30 was manufactured by way of example. The overall structure was glass substrate / ITO / MoO ₃ (10 nm) / DBP: C ₇₀ (1: 8) (54 nm) / C ₇₀ (9 nm) / buffer / Al (100 nm). The devices were grown on commercially purchased pre-patterned ITO substrates. The substrate was cleaned using a solvent and a UV-ozone system. The organic layer, the metal oxide, and the cathode were deposited in a thermal evaporator at a rate of 0.1 nm / sec. An epoxy layer was placed around the device and the glass slide on the top surface was squeezed to seal the device. The epoxy was UV cured.

In one device, the buffer layer was a mixed layer of BPhen: C ₆₀ (1: 1) (10 nm) and BPhen cap layer (5 nm). In another device, the buffer layer was a mixed layer of TPBI: C ₇₀ (1: 1) (10 nm) and TPBi cap layer (3 nm). It is noted that other broad energy gap materials such as those listed in Table 10 below and discussed above may be used.

To test the lifetime at increased temperature, the device was placed on a carrier substrate made from a printed circuit board. The contacts were soldered. A copper plate was attached to a device having a resistance heater for distributing heat across the entire device area. The temperature was measured using a thermocouple. The device was illuminated at 1000 W / m &lt; 2 &gt; using a xenon arc-lamp and measured every 30 minutes using a current-voltage source meter controlled by a Matlab program.

Figures 31a-c show normalized performance values for devices using BPhen at various temperatures, and Figures 32a-d show normalized performance values for devices using TPBi at various temperatures. Due to the morphological instability of BPhen compared to TPBi as shown by these respective Tg's, as shown in Figs. 31a-c and 32a-d , the performance of the device using BPhen increases with TPBi Using the device degraded considerably faster over time.

Example  22

The device shown in Fig. 33 was made illustratively using the same technique described in Example 21. The overall structure is as shown in Table ₁ , with glass substrate / ITO / MoO ₃ (10 nm) / C ₇₀ : DBP (8: 1) (54 nm) / C ₇₀ (9 nm) / buffer (100 nm), and the buffer layer has a wide energy gap material and a mixed layer of an electron conductive material, and includes a cap layer of a wide energy gap material. It is noted that other wide energy gap materials such as those discussed above may be used. Figure 33 shows the relative normalization at 55 [deg.] C of a device using BPhen in a full layer compared to three devices using different wide energy gap materials with higher T _g than BPhen, i.e., BAlq, 3TPYMB, and TPBi, Power conversion efficiency.

As shown in Figure 33 , the device performance was considerably less over time for a device comprising a mixed fill layer having a broad energy gap material with a higher Tg than BPhen. Other large energy gap materials - Alq ₃ and BP4mPy - a molecular structure of such materials with a molecular structure of are shown in Figure 34-38.

Figures 39-41 show normalized reactivity, fill factor, V _OC , and PCE over time at 55 ° C for devices with C ₇₀ and mixed buffers containing one of TPBi, 3TPYMB, and BAlq, respectively. The normalized performance values of the device comprises one of, TPBi, 3TPYMB, and BAlq as shown performance of the device that includes a (e.g., PCE, based also on V _OC, FF, and R) is BPhen (Fig. 31a -c and the performance of the BPhen device shown in Figure 33 ).

Example  23

106℃)을 포함하는 완충제 층이었다. 증가된 온도에서의 디바이스의 수명을 실시예 21에 기재된 것과 동일한 기술을 사용하여 시험하였다. 도 43-46은 각각 55℃, 70℃, 85℃, 및 100℃에서의 도 42의 디바이스에 대한 시간에 걸친 정규화된 반응도, 필 팩터, V_OC, 및 PCE를 나타낸다. The device shown in Fig. 42 was made illustratively using the same technique described in Example 21. The entire structure of glass substrate / ITO (160 nm) / MoO 3 (10nm) / C 70: DBP (8: 1) (54 nm) / C 70 (9 nm) / 3TPYMB: C 60 (1: 1) (10 nm) / Al (100 nm). 3TPYMN: C 10 nm of layer ₆₀ is a wide bandgap material 3TPYMB (the T _g 3TPYMB

106 &lt; 0 &gt; C). The lifetime of the device at the increased temperature was tested using the same technique as described in Example 21. Figures 43-46 show the normalized reactivity, fill factor, V _OC , and PCE over time for the device of Figure 42 at 55 ° C, 70 ° C, 85 ° C, and 100 ° C, respectively.

Claims (20)

An organophotoreceptive optoelectronic device,
Two electrodes in an overlapping relationship comprising an anode and a cathode;
A photoactive region comprising at least one donor material and at least one acceptor material disposed between two electrodes forming a donor-acceptor heterojunction, wherein the at least one acceptor material has a lowest unoccupied molecular orbital energy level (LUMO _Acc ) and a peak At least one donor material having an occupied molecular orbital energy level (HOMO _Acc ), a photoactive region having a lowest unoccupied molecular orbital energy level (LUMO _don ) and a highest occupied molecular orbital energy level (HOMO _don ); And
An exciton-blocking electronic filter disposed between the cathode and the at least one receiver material, wherein the electronic filter comprises a mixture comprising at least one of a wide energy gap material on the cathode side and one or more electronically conductive materials, The energy gap material,
- lowest unoccupied molecular orbital energy level (LUMO _CS-WG ) less than or equal to LUMO _Acc ;
- the highest occupied molecular orbital energy level (HOMO _{CS - WG} ) that is greater than, equal to, or less than, 0.3 eV HOMO _Acc ; And
- HOMO _Acc -LUMO _ACC wider than the energy gap of HOMO _{CS - WG} -LUMO _{CS - WG} Energy Gap
To have;
The wide energy gap material on at least one cathode side is an exciton-blocking electronic filter having a glass transition temperature of &lt; RTI ID = 0.0 &gt; 85 C &
/ RTI &gt; The method of claim 1, wherein the wide energy gap material on at least one cathode side is selected from the group consisting of 3,3 ', 5,5'-tetra [(m-pyridyl) (1-phenyl-1-H-benzimidazole) (TPBi), bis (2-methyl-8- quinolinolate) - Aluminum (Alq3), tris (2,4,6-trimethyl-3- (pyridin-3-yl) phenyl) borane (3TPYMB), 4,40- (1,3-phenylene) bis (2,6-dip-tolylpyridine-3,5-dicarbonitrile) (M-PhPyCN), 4,40- (1,3-phenylene) bis (2,6-di (biphenyl-4-yl) pyridine-3,5-dicarbonitrile) Phenyl-4-p-tolylnicotinonitrile) (p-tert-butylphenol) An organic photosensitive photoelectron including a material selected from 4,4'- (PPtNN), 4,40- (1,4-phenylene) bis (2-phenyl-6-p- tolylnicotinonitrile) device. The organic photosensitive optoelectronic device according to claim 1, wherein the broad energy gap material has a glass transition temperature of 85-200 占 폚. The organic photosensitive optoelectronic device according to claim 1, wherein the broad energy gap material has a glass transition temperature of 100-165 &lt; 0 &gt; C. The organic photosensitive optoelectronic device according to claim 1, wherein HOMO _{CS - WG} is greater than HOMO _Acc and LUMO _{CS - WG} is less than LUMO _Acc . 2. The organic photosensitive optoelectronic device according to claim 1, wherein LUMO _EC is equal to LUMO _Acc . 2. The organic photosensitive optoelectronic device according to claim 1, wherein the LUMO _EC is greater than the LUMO _Acc . The organic photosensitive optoelectronic device according to claim 1, wherein LUMO _{CS - WG} is smaller than LUMO _EC . The method of claim 1, wherein the at least one receptor material is selected from the group consisting of subphthalocyanine, subnaphthalocyanine, dipyrin complex, BODIPY complex, perylene, naphthalene, fullerene, functionalized fullerene derivatives, A photosensitive optoelectronic device. 10. An organic photosensitive optoelectronic device according to claim 9, wherein the at least one receptor material comprises a material selected from fullerenes. The method of claim 1, wherein the at least one electron conductive material comprises a material selected from subphthalocyanine, subnaphthalocyanine, dipyrin complex, BODIPY complex, perylene, naphthalene, fullerene, functionalized fullerene derivatives, Organic photosensitive optoelectronic devices. The organic photosensitive optoelectronic device according to claim 1, wherein the at least one receptor material and the at least one electron conductive material comprise the same material. An organophotoreceptive optoelectronic device,
Two electrodes in an overlapping relationship comprising an anode and a cathode;
A photoactive region comprising at least one donor material and at least one donor material disposed between two electrodes forming a donor-acceptor heteromeric junction, wherein the at least one donor material has a lowest unoccupied molecular orbital energy level (LUMO _don ) and a peak A photoactive region having an occupied molecular orbital energy level (HOMO _don ); And
An exciton-blocking hole filter disposed between the anode and the at least one donor material, wherein the hole filter comprises a mixture comprising at least one of a wide energy gap material at the anode side and at least one hole-conducting material, The energy gap material,
- greater than the HOMO _don, or the same highest occupied molecular orbital energy levels (HOMO _AS-WG) therewith;
- the lowest unoccupied molecular orbital energy level (LUMO _{AS - WG} ) that is less than, equal to, or within 0.3 eV of LUMO _don ; And
- _don -LUMO _don HOMO energy gap wider than the HOMO _{AS - AS} -LUMO _{WG - WG} energy gap
To have;
Here, the wide energy gap material on at least one anode side is an exciton-blocking hole filter having a glass transition temperature of 85 DEG C or higher
/ RTI &gt; 14. The method of claim 13, wherein the broad energy gap material on at least one cathode side is selected from the group consisting of 3,3 ', 5,5'-tetra [(m-pyridyl) (1-phenyl-1-H-benzimidazole) (TPBi), bis (2-methyl-8- quinolinolate) - Aluminum (Alq3), tris (2,4,6-trimethyl-3- (pyridin-3-yl) phenyl) borane (3TPYMB), 4,40- (1,3-phenylene) bis (2,6-dip-tolylpyridine-3,5-dicarbonitrile) (M-PhPyCN), 4,40- (1,3-phenylene) bis (2,6-di (biphenyl-4-yl) pyridine-3,5-dicarbonitrile) Phenyl-4-p-tolylnicotinonitrile) (p-tert-butylphenol) An organic photosensitive photoelectron including a material selected from 4,4'- (PPtNN), 4,40- (1,4-phenylene) bis (2-phenyl-6-p- tolylnicotinonitrile) device. 14. The organophotoreceptor optoelectronic device of claim 13, wherein the wide energy gap material has a glass transition temperature of from 85 占 폚 to 200 占 폚. 14. The organic photosensitive optoelectronic device of claim 13, wherein the HOMO _{AS - WG} is greater than the HOMO _don and the LUMO _{AS - WG} is less than the LUMO _don . 14. The organic photosensitive optoelectronic device according to claim 13, wherein the HOMO _HC is equal to or less than HOMO _don . 14. The organic photosensitive optoelectronic device according to claim 13, wherein the HOMO _{AS - WG} is larger than the HOMO _HC . 14. The method of claim 13, wherein the at least one donor material is selected from the group consisting of phthalocyanine, subphthalocyanine, naphthalocyanine, merocyanine dye, boron-dipyrromethene (BODIPY) dye, thiophene, (DIP), squalaine (SQ) dyes, tetraphenyldibenzopiperflanthene (DBP), and derivatives thereof. The method of claim 13, wherein the at least one hole-conducting material is selected from the group consisting of phthalocyanine, subphthalocyanine, naphthalocyanine, merocyanine dye, boron-dipyrromethene (BODIPY) dye, thiophene, Wherein the organic photoconductive device comprises a material selected from the group consisting of diallyl (DIP), squalane (SQ) dyes, tetraphenyldibenzopiperflanthene (DBP), and derivatives thereof.

Images