CN106025070A - Photomultiplier organic light detector with spectral selectivity and preparation method of photomultiplier organic light detector - Google Patents

Abstract

The invention provides a photomultiplier organic light detector with spectral selectivity. The photomultiplier organic light detector comprises a transparent substrate (1), a transparent electrode (2), a transparent electrode modifying layer (3), an active layer (4) and a metal electrode (5), wherein the transparent electrode (2) is arranged on the transparent substrate (1); the transparent electrode modifying layer (3) is arranged on the transparent electrode (2); the active layer (4) is arranged on the transparent electrode modifying layer (3); the metal electrode (5) is arranged on the active layer (4); the active layer is a blend film of an electron donor material and an electron acceptor material; the thickness of the film is 2.0-5.0 microns; the weight ratio of an electron donor material to the electron acceptor material in the active layer is 100 to 1; the electron donor material is a poly(3-exylthiophene) (P3HT) or perylene polymer (PBDT-TS1); and the electron acceptor material is a fullerene derivative (PCBM, ICBA) or a non-fullerene receptor (ITIC).

Description

Photomultiplier organic photodetector with spectral selectivity and preparation method thereof

technical field

The invention relates to the field of light detection. More specifically, it relates to a photomultiplier organic photodetector with spectral selectivity and a preparation method thereof.

Background technique

Organic semiconductor materials have attracted much attention because of their high extinction coefficient, low cost, green, and large-area flexible devices. With the continuous development of organic semiconductor materials, the performance of optoelectronic devices based on organic materials has also been greatly improved, and the research on organic photodetectors has also attracted people's attention. The organic photodetectors reported in the literature are mainly based on the organic photovoltaic effect. The organic material captures solar photons to generate excitons. The excitons diffuse to the interface of the acceptor material and dissociate into free carriers. The carriers are collected by the electrodes, thereby generating a photo-generated current and realizing the detection and response to light. Due to the influence of material extinction coefficient, exciton dissociation efficiency, carrier transport and collection efficiency, the external quantum efficiency of this type of photodetector is less than 100%. For weak light or ultra-weak light detection, the responsivity of the device is restricted. Therefore, in practical applications, this type of detector needs to add a preamplifier to sample and amplify the weak electrical signal, so as to realize the detection of weak light, and the use of the preamplifier will increase the cost of the detection system and bring Come new noises.

Based on the photovoltaic effect, it is impossible to directly prepare an organic photodetector with spectral selectivity. High-efficiency exciton dissociation and carrier transport are realized. The two organic semiconductor materials make the spectral response range of the device wider, and the prepared organic photodetector has no spectral selectivity, and its spectral response range is generally greater than 100nm. Spectrally selective organic photodetectors are widely used in many fields, such as imaging, medical sensing, security systems, etc. The common feature of these fields is the need to detect light in a specific wavelength range while ignoring background noise. In order to improve the spectral selectivity of organic photodetectors, it is common practice to couple a photodetector with a wide spectral response range to a dichroic prism or a bandpass optical filter. This will undoubtedly increase the manufacturing cost of the organic photodetector and the complexity of the application, and will also lead to a decrease in device performance. In addition, commercial bandpass optical filters do not cover all bands required for applications, resulting in devices with full width at half maximum (FWHM) greater than 50nm.

Contents of the invention

An object of the present invention is to provide a photomultiplier organic photodetector with spectral selectivity, which realizes photomultiplier and spectral selection functions at a lower cost and with a simple device structure.

Another object of the present invention is to provide a method for preparing a photomultiplier organic photodetector with spectral selectivity, which realizes photomultiplication and spectral selection functions with a simple preparation method.

To achieve the above object, the present invention adopts the following technical solutions:

Photomultiplier organic photodetectors with spectral selectivity, including:

transparent base(1);

a transparent electrode (2) arranged on the transparent substrate (1);

a transparent electrode modification layer (3) disposed on the transparent electrode (2);

an active layer (4) disposed on the transparent electrode modification layer (3); and

a metal electrode (5) disposed on the active layer (4),

Wherein, the active layer is a blend film of an electron donor material and an electron acceptor material, and the thickness of the film is 2.0-5.0 μm; the weight ratio of the electron donor and the electron acceptor material in the active layer is 100:1; wherein, the electron donor material is poly(3-hexylthiophene) (P3HT) or perylene polymer (PBDT-TS1), and the electron acceptor material is fullerene derivative (PCBM, ICBA ) or non-fullerene acceptors (ITIC).

Preferably, the transparent substrate is glass.

Preferably, the transparent electrode is indium tin oxide (ITO).

Preferably, the transparent electrode modification layer is made of poly(3,4-ethylenedioxythiophene)-polystyrenesulfonic acid (PEDOT:PSS), molybdenum oxide (MoO ₃ ) or [9,9-dioctylfluorene- 9,9-bis(N,N-dimethylaminopropyl)fluorene] (PFN).

Preferably, the metal electrode is made of aluminum or silver with a thickness of 100 nm.

Preferably, the thickness of the blended film of the active layer is 2.0 μm.

A method for preparing a photomultiplier organic photodetector with spectral selectivity, comprising the following steps:

Step 1: Use glass as a transparent substrate;

Step 2: preparing a transparent electrode on the transparent substrate;

Step 3: preparing a transparent electrode modification layer on the transparent electrode;

Step 4: Prepare an active layer on the transparent electrode modification layer, including: using poly(3-hexylthiophene) (P3HT) or perylene polymer (PBDT-TS1) as an electron donor material, derivatizing fullerene (PCBM, ICBA) or non-fullerene acceptor (ITIC) as the electron acceptor material; The electron donor material and the electron acceptor material are dissolved in o-dichlorobenzene (o- In DCB), a mixed solution is prepared, and the mixed solution is uniformly drip-coated on the prepared transparent electrode modification layer, and then heated to quickly volatilize o-dichlorobenzene (o-DCB), leaving a thickness of 2.0-5.0μm Electron A blended thin film of a donor material and an electron acceptor material is used as an active layer, wherein the heating temperature is 80-120°C;

Step 5: preparing metal electrodes on the active layer.

Preferably, step 2 further includes: plating indium tin oxide (ITO) on the transparent substrate, then soaking in deionized water and absolute ethanol respectively, and cleaning with an ultrasonic cleaner; blowing with nitrogen after cleaning dry, and then treated with a plasma cleaner for 1 min.

Preferably, step 3 further includes: spin-coating poly(3,4-ethylenedioxythiophene)-polystyrenesulfonic acid (PEDOT:PSS) or [9,9-dioctyl] on the transparent electrode prepared in step 2 Fluorene-9,9-bis(N,N-dimethylaminopropyl)fluorene] (PFN), where the spin-coating rate is 5000r/min, the spin-coating time is 40s, poly(3,4-ethylenedioxythiophene) - The amount of polystyrene sulfonic acid (PEDOT:PSS) is 80 μL; after spin coating, put it on a heating platform at 150 ° C for 10 min; or evaporate a Molybdenum oxide (MoO ₃ ) layer 10 nm thick.

Preferably, step 5 further includes: putting the sample obtained in step 4 into a vacuum chamber with an aluminum wire, and the vacuum degree of the vacuum chamber is lower than 1×10 ^-4 Pa; heating the aluminum wire to make it evaporate, and the evaporation rate is It is 0.2nm/s, and the evaporation thickness is 100nm.

The beneficial effects of the present invention are as follows:

1. The full width at half maximum (FWHM) of the organic photodetector method is less than 30nm, and then has spectral selectivity;

2. The organic photodetector has an external quantum efficiency greater than 100% and the device structure is simple;

3. The preparation method of the organic photodetector is economical and simple.

Description of drawings

The specific implementation manners of the present invention will be further described in detail below in conjunction with the accompanying drawings.

Fig. 1 shows a schematic diagram of the structure of the organic photodetector of the present invention.

FIG. 2 shows the external quantum efficiency spectrum curve of the organic photodetector based on the active layer of 1.0 μm thick P3HT:PCBM (100:1) under the bias voltage of -20V according to the present invention.

Fig. 3 shows that based on 2.0 μm, 2.5 μm, 5.0 μm and 7.5 μm thick P3HT: PCBM (100:1) is the external quantum efficiency spectral curve of the organic photodetector of active layer under-20V bias .

Fig. 4 shows a flow chart of the method of the present invention.

FIG. 5 shows the external quantum efficiency spectrum curve of the organic photodetector based on the active layer of 2.0 μm thick P3HT:PCBM (100:1) under the bias voltage of -20V.

FIG. 6 shows the sensitivity curve of the organic photodetector based on the active layer of 2.0 μm thick P3HT:PCBM (100:1) under the bias voltage of -20V according to the present invention.

detailed description

In order to illustrate the present invention more clearly, the present invention will be further described below in conjunction with preferred embodiments and accompanying drawings. Similar parts in the figures are denoted by the same reference numerals. Those skilled in the art should understand that the content specifically described below is illustrative rather than restrictive, and should not limit the protection scope of the present invention.

As shown in Figure 1, a photomultiplier organic photodetector with spectral selectivity includes a transparent substrate 1; a transparent electrode 2 arranged on the transparent substrate 1; a transparent electrode modification layer 3 arranged on the transparent electrode 2; an active layer 4 arranged on the transparent electrode modification layer 3; and a metal electrode 5 arranged on the active layer (4).

The transparent substrate 1 is glass, the transparent electrode 2 is indium tin oxide (ITO), and the transparent electrode modification layer 3 is poly(3,4-ethylenedioxythiophene)-polystyrenesulfonic acid (PEDOT: PSS), molybdenum oxide (MoO ₃ ) or [9,9-dioctylfluorene-9,9-bis(N,N-dimethylaminopropyl)fluorene] (PFN).

The active layer 4 is a blended film of an electron donor material and an electron acceptor material. In the present invention, the thickness of the blended film is selected to be 2.0-5.0 μm. The electron donor material is poly(3-hexylthiophene) (P3HT) or perylene polymer (PBDT-TS1), and the electron acceptor material is fullerene derivative (PCBM, ICBA) or non-fullerene acceptor (ITIC ), the electron donor and acceptor materials are in a ratio of 100:1 by weight.

Wherein, the weight ratio of the electron-donor-acceptor material of the active layer 4 is 100:1, and the photomultiplier response is obtained by using a small amount of electron-acceptor mass ratio in the device, and the device has an external quantum efficiency greater than 100%, while reducing The preparation cost of the device is reduced; by adjusting the thickness of the active layer, the organic photodetector has spectral selectivity.

Specifically, the absorption of one photon by the active layer 4 can cause many carriers to flow through the device, thereby obtaining a larger photocurrent. The working mechanism is: electrons in traps near the interface induce interface energy band bending, thereby reducing The hole injection barrier enhances the tunneling injection of holes from the external circuit and obtains a larger photocurrent.

It should be noted that if the thickness of the blended film of the active layer 4 is less than 2.0 μm, as shown in Figure 2, the external quantum efficiency of the device will also produce an external quantum efficiency peak at the short wavelength band, and the device will be stable in the full spectral range. There are two external quantum efficiency peaks, which affect the spectral selectivity of the device; as shown in Figure 3, the external quantum efficiency of the device will decrease with the increase of the thickness of the active layer 4 blended film, if the active layer 4 The thickness of the blended film is between 5.0-7.5 μm. Although the quantum efficiency inside and outside the partial thickness range is still greater than 100%, considering the error in practical applications, in order to ensure that the device still has a photoelectric multiplication effect, the blended film should be maintained at 2.0 Between -5.0μm.

Furthermore, 2.0 μm and 5.0 μm are two critical values for the organic photodetector to maintain narrow-band detection (ie, spectral selectivity) and photomultiplier response in practical applications.

As shown in Figure 4, the preparation process of the organic photodetector is as follows:

Step 1: Use glass as a transparent substrate.

Step 2: Plating indium tin oxide (ITO) on the transparent substrate, then soaking in deionized water and absolute ethanol respectively, and then cleaning with an ultrasonic cleaner; after cleaning, blow dry with nitrogen, and then use plasma Washing instrument for 1min.

Step 3: Spin-coat poly(3,4-ethylenedioxythiophene)-polystyrenesulfonic acid (PEDOT:PSS) or [9,9-dioctylfluorene on the indium tin oxide (ITO) layer in step 2 -9,9-bis(N,N-dimethylaminopropyl)fluorene](PFN), the spin coating speed is 5000r/min, the spin coating time is 40s, poly(3,4-ethylenedioxythiophene)-poly The amount of styrene sulfonic acid (PEDOT:PSS) is 80 μL; after the spin coating is completed, place it on a heating platform at 150 ° C for 10 min; Plating a layer of molybdenum oxide (MoO ₃ ) with a thickness of 10nm.

Step 4: Using poly(3-hexylthiophene) (P3HT) or perylene polymer (PBDT-TS1) as the electron donor material, fullerene derivatives (PCBM, ICBA) or non-fullerene acceptors (ITIC ) as an electron acceptor material; the electron donor material and the electron acceptor material are dissolved in o-dichlorobenzene (o-DCB) according to a weight ratio of 100:1 to prepare a mixed solution, and the mixed solution is uniformly Drop-coat on the poly(3,4-ethylenedioxythiophene)-polystyrenesulfonic acid (PEDOT:PSS) layer in step 3, and then heat to make o-dichlorobenzene (o-DCB) volatilize quickly, leaving electrons for A blended film of a bulk material and an electron acceptor material, wherein the heating temperature is 80-120° C., and the thickness of the blended film is 2.0-5.0 μm.

Step 5: Put the sample obtained in step 4 into a vacuum chamber with an aluminum wire, the vacuum degree of the vacuum chamber is lower than 1×10 ^-4 Pa; heat the aluminum wire to evaporate it, and the evaporation rate is 0.2nm/s , the evaporation thickness is 100nm, and a photomultiplier organic photodetector with spectral selectivity is obtained.

Embodiment one

The photomultiplier organic photodetector with spectral selectivity comprises: a transparent substrate 1 , a transparent electrode 2 , a transparent electrode modification layer 3 , an active layer 4 and a metal electrode 5 .

The transparent electrode 2 is a transparent ITO electrode; the transparent electrode modification layer 3 is poly(3,4-ethylenedioxythiophene)-polystyrenesulfonic acid (PEDOT:PSS); the active layer 4 is poly The blend film of (3-hexylthiophene) P3HT and fullerene derivative PCBM, wherein, the mass ratio of poly(3-hexylthiophene) P3HT and fullerene derivative PCBM is 100:1, and the thickness of active layer 4 is 2.0 μm; the metal electrode 5 is aluminum.

The preparation method of the above-mentioned organic photodetector comprises the following steps:

Step ¹ : Use glass with an area of 4cm2 as a transparent substrate.

Step 2: Plating indium tin oxide (ITO) on the transparent substrate, then soaking in deionized water and absolute ethanol respectively, cleaning with an ultrasonic cleaner; blowing dry with nitrogen after cleaning, and drying the dried substrate The bottom surface is treated with a plasma cleaner for 1 min to improve the cleanliness of the substrate surface and the work function of the ITO surface.

Step 3: Spin-coat PEDOT:PSS on the ITO-coated glass substrate processed in step 2, with a spin-coating rate of 5000r/min, a capacity of 80μL, and a spin-coating time of 40s, and then place it on a heating stage at 150°C Anneal for 10 minutes to remove the moisture in the PEDOT:PSS film.

Step 4: Dissolve poly(3-hexylthiophene) P3HT and fullerene derivative PCBM in o-dichlorobenzene (o-DCB) at a weight ratio of 100:1 to prepare a 40 mg/ml mixed solution, and take 50 μL of mixed The solution was uniformly drop-coated on the PEDOT:PSS/ITO substrate, and then the substrate was transferred to a heating platform at 80°C to quickly evaporate the solvent in the film to prepare a 2.0 μm mixed film.

Step 5: put the sample into a vacuum chamber, and evacuate the vacuum chamber to make the vacuum degree reach 4×10 ^-5 Pa. The aluminum wire is heated to evaporate the aluminum wire with an evaporation rate of 0.2nm/s and an evaporation thickness of 100nm to obtain a photomultiplier organic photodetector with spectral selectivity.

As shown in Figures 5 and 6, the fabricated 2.0μm active hybrid thin film organic photodetector has a maximum external quantum efficiency of 610% at 645nm and a detection sensitivity of 1.71×10 ¹⁴ Jones under a bias voltage of -20V.

The blend film prepared by mixing the electron donor material poly(3-hexylthiophene) (P3HT) and the electron acceptor material fullerene derivative (PCBM) at a weight ratio of 100:1 in the active layer 4 reduces the electron acceptor in The mass ratio in the device obtains a photoelectric multiplication effect, that is, the organic photodetector has an external quantum efficiency greater than 100%, and at the same time reduces the preparation cost of the device; by regulating the thickness of the blend film, that is, the active layer, the organic The photodetector has spectral selectivity; specifically, setting the thickness of the active layer blend film to 2.0 μm makes the full width at half maximum (FWHM) of the organic photodetector less than 30 nm, thus having spectral selectivity.

Embodiment two

The active layer 4 blend film thickness in embodiment one is respectively set to 2.5 μm and 5.0 μm, as shown in Figure 3, the organic photodetector external quantum efficiency of two kinds of situations is all greater than 100%, full width at half maximum (FWHM ) are less than 30nm, and then all have spectral selectivity.

Apparently, the above-mentioned embodiments of the present invention are only examples for clearly illustrating the present invention, and are not intended to limit the implementation of the present invention. Those of ordinary skill in the art can also make There are other different forms of changes or changes, such as the preparation of the active layer, there are many options, and the electron donor material can be any one of poly(3-hexylthiophene) (P3HT) and perylene polymer (PBDT-TS1) The electron acceptor material can be any one of fullerene derivatives (PCBM, ICBA) or non-fullerene acceptors (ITIC), and it is impossible to exhaustively enumerate all the implementation modes here, and those belonging to the technology of the present invention Obvious changes or variations derived from the scheme are still within the protection scope of the present invention.

Claims (10)

1. there is the photomultiplier transit type organic photodetector of spectral selection, including:

Transparent substrates (1)；

The transparency electrode (2) being arranged in this transparent substrates (1)；

The transparency electrode decorative layer (3) being arranged in this transparency electrode (2)；

It is arranged on the active layer (4) on this transparency electrode decorative layer (3)；And

The metal electrode (5) being arranged on this active layer (4)；

It is characterized in that, described active layer is the blend film of electron donor material and electron acceptor material, Described film thickness is 2.0-5.0 μm；Electron donor and the weight ratio of electron acceptor material in described active layer For 100:1；Wherein, described electron donor material is poly-(3-hexyl thiophene) (P3HT) or birds of the same feather flock together Compound (PBDT-TS1), described electron acceptor material be fullerene derivate (PCBM, ICBA) or Non-fullerene acceptor (ITIC).

Organic photodetector the most according to claim 1, it is characterised in that described transparent substrates is Glass.

Organic photodetector the most according to claim 1, it is characterised in that described transparency electrode is Indium tin oxide (ITO).

Organic photodetector the most according to claim 1, it is characterised in that described transparency electrode is repaiied Decorations layer is by poly-(3,4-ethene dioxythiophene)-polystyrolsulfon acid (PEDOT:PSS), molybdenum oxide (MoO₃) Or [double (N, the N-DimethylAminopropyl) fluorenes of 9,9-dioctyl fluorene-9,9-] (PFN) is constituted.

Organic photodetector the most according to claim 1, it is characterised in that described metal electrode is Aluminum or silver, thickness is 100nm.

Organic photodetector the most according to claim 1, it is characterised in that being total to of described active layer Mixed film thickness is 2.0 μm.

7. there is the preparation method of the photomultiplier transit type organic photodetector of spectral selection, it is characterised in that Said method comprising the steps of:

Step 1: using glass as transparent substrates；

Step 2: prepare transparency electrode in described transparent substrates；

Step 3: prepare transparency electrode decorative layer in described transparency electrode；

Step 4: prepare active layer on described transparency electrode decorative layer, including: by poly-(3-hexyl thiophene) Or base polymer (PBDT-TS1) is as electron donor material, by fullerene derivate (P3HT) (PCBM, ICBA) or non-fullerene acceptor (ITIC) are as electron acceptor material；Described electronics is given Body material and described electron acceptor material are dissolved in o-dichlorohenzene (o-DCB) according to weight ratio 100:1, system Standby one-tenth mixed solution, by uniform for described mixed solution drop coating on the transparency electrode decorative layer of preparation, then adds Heat makes o-dichlorohenzene (o-DCB) quickly volatilize, and leaving thickness is 2.0-5.0 μm electron donor material and electricity The blend film of sub-acceptor material is as active layer, and wherein, described heating-up temperature is 80-120 DEG C；

Step 5: prepare metal electrode on described active layer.

Method the most according to claim 7, it is characterised in that step 2 farther includes: by indium Tin-oxide (ITO) is plated in described transparent substrates, is soaked in deionized water, dehydrated alcohol the most respectively In, then clean with ultrasonic washing instrument；Dry up with nitrogen after cleaning up, then with at plasma cleaning instrument Reason 1min.

Method the most according to claim 7, it is characterised in that step 3 farther includes: in step Spin coating poly-(3,4-ethene dioxythiophene)-polystyrolsulfon acid in the transparency electrode of preparation in rapid 2 (PEDOT:PSS) or [9,9-dioctyl fluorene-9,9-double (N, N-DimethylAminopropyl) fluorenes] (PFN), wherein Spin coating speed is 5000r/min, spin-coating time 40s, poly-(3,4-rthylene dioxythiophene)-polystyrene sulphur Acid (PEDOT:PSS) consumption is 80 μ L；Annealing 10min it is placed on the warm table of 150 DEG C after spin coating； Or it is deposited with the thick molybdenum oxide of one layer of 10nm with the speed of 0.2nm/s in the transparency electrode prepared in step 2 (MoO₃)。

Method the most according to claim 7, it is characterised in that step 5 farther includes: will The sample obtained in step 4 is put in the vacuum chamber being placed with aluminium wire, and described vacuum degree in vacuum chamber is less than 1 ×10^-4Pa；Heating aluminium wire makes it evaporate, and evaporation rate is 0.2nm/s, and evaporation thickness is 100nm.