CN111418036A

CN111418036A - Nickel oxide modified graphene oxide nanocomposites as hole transport layers and methods of making the same

Info

Publication number: CN111418036A
Application number: CN201780096839.1A
Authority: CN
Inventors: 蔡植豪; 成佳淇
Original assignee: University of Hong Kong HKU
Current assignee: University of Hong Kong HKU
Priority date: 2017-11-14
Filing date: 2017-11-14
Publication date: 2020-07-14
Anticipated expiration: 2037-11-14
Also published as: WO2019095091A1; CN111418036B

Abstract

Method for providing GO NiO-based optical fiber for photoelectric device_xA film of a nanocomposite. The method comprises preparing a GO solution in a first alcohol solvent by oxidation of graphite, preparing NiO in a second alcohol solvent by a solvothermal method_xSolution GO by mixing GO solution with NiO_xSolution blending to make NiO_xModification onto GO Nanosheet Structure (NS) to obtain NiO_xSolution, and by using GO: NiO_xSolution to form GO: NiO based_xA film of a nanocomposite.

Description

Nickel oxide modified graphene oxide nanocomposites as hole transport layers and methods of making the same

Technical Field

The present invention relates generally to optoelectronics, and more particularly to nickel oxide modified graphene oxide and methods thereof.

Background

Inverted (inverted) Organic Solar Cells (OSCs) with extended stability are widely adopted, taking advantage of the elimination of both hygroscopic acidic poly (3, 4-ethylenedioxythiophene): poly (styrenesulfonic acid) (PEDOT: PSS) and a low Work Function (WF) cathode which is easily oxidized. Conventional molybdenum oxide (MoO)₃) Transition metal oxides have been widely used as hole transport layers (HT L) on top of organic active layers in inverted OSCs (hereinafter referred to as top HT L)₃The most reported optimum thickness of GO for use as HT L in inverted OSC is only 1-2nm, which is the thickness of several GO sheets.

Solution treated nickel oxide (NiO)_xWhere x is a positive number) is a p-type semiconductor with the following advantages: good conductivity and electron blocking ability. However, most of the reported NiO_xHT L applications involve post-treatments including oxygen plasma treatment, ultraviolet ozone (UVO) treatment, or annealing at high temperatures_xHT L preparation method was incompatible with the use of top HT L in inverted OSC recently, solution-treated NiO without post-treatment_xNanoparticles (NPs) have been reported for HT L applications, however, NiO_xNPs are only well dispersed in water, which hinders their use in inverted OSCs because of poor wetting properties of water on the surface of the hydrophobic active layer.

Summary of The Invention

Embodiments of the subject invention provide a novel and advantageous optoelectronic device comprising nickel oxide modified with graphene oxide as a nanocomposite-based HT L, thereby providing a high performance inverted OSC.

In one embodiment, GO: NiO based materials for optoelectronic devices are prepared_xMembrane (i.e., GO: NiO)_xNanocomposite membranes) may include preparing a GO solution in a first alcohol solvent by oxidation of graphite, preparing NiO in a second alcohol solvent by a solvothermal method_xSolution by mixing GO solution with NiO_xSolution blending to make NiO_xDecorating onto GO nano-sheet structures (NS) to obtain GO: NiO_xNanocomposite solution, and forming GO: NiO based by using the same_xA film of a nanocomposite.

In another embodiment, an optoelectronic device can comprise a first electrode layer, an electron transport layer on the first electrode layer, an organic active layer disposed on the first electron transport layer, a first organic active layer disposed on the organic active layer and comprising GO: NiO_xA hole transport layer of a nanocomposite material, and a second electrode layer disposed on the hole transport layer.

Brief Description of Drawings

FIG. 1a shows NiO in ethanol according to an exemplary embodiment_xNP, L-GO NS, H-GO NS and L-GO NiO_xAnd H-GO: NiO_xPhoto of the nanocomposite.

FIG. 1b shows C1s XPS spectra for L-GO and H-GO according to an exemplary embodiment.

FIG. 1c shows FTIR spectra (at 1625 cm) of L-GO and H-GO according to one exemplary embodiment^-1Normalized at (v).

FIG. 2a shows a Transmission Electron Microscope (TEM) image of L-GO NS according to an exemplary embodiment.

FIG. 2b shows NiO according to an exemplary embodiment_xTEM images of NP-modified L-GO NS nanocomposites.

FIG. 2c shows H-GO: NiO according to an exemplary embodiment_xTEM images of the aggregates.

FIG. 2d shows L-GO: NiO according to an exemplary embodiment_xSEM image of the film.

FIG. 3a shows a solar cell (ITO/ZnO/PTB7-Th: PC) according to an exemplary embodiment₇₁BM/HT L/Ag).

FIG. 3b shows the structure of a solar cell (ITO/ZnO/PBDB-T: ITIC/HT L/Ag) according to an exemplary embodiment.

FIG. 3c shows the structure of a solar cell (ITO/ZnO/PBDB-T: IT-M/HT L/Ag) according to one exemplary embodiment.

FIG. 4a is a diagram illustrating a PC with ITO/ZnO/PTB7-Th in accordance with one or more embodiments₇₁BM/L-GO:NiO_xInverted OSC of structure/Ag with ITO/ZnO/PTB7-Th PC₇₁Comparison of control devices with structures of BM/L-GO/Ag at a light intensity of 100mW/cm²Graph of current density-voltage (J-V) characteristics at am1.5g solar spectrum.

FIG. 4b is a graph illustrating GO-based inverted OSCs and L-GO: NiO having different thicknesses in accordance with one or more embodiments_xA diagram of a PCE inverting the OSC of (inset shows having ITO/ZnO/PTB7-Th: PC₇₁BM/L-GO:NiO_xCross-section SEM of device of structure/Ag).

FIG. 5a is a schematic representation of a film having ITO/ZnO/PBDB-T: ITIC/L-GO: NiO according to one or more embodiments_xInverted OSC of the/Ag structure at a light intensity of 100mW/cm compared to a control device having a structure of ITO/ZnO/PBDB-T ITIC/L-GO/Ag²Graph of current density-voltage (J-V) characteristics at am1.5g solar spectrum.

FIG. 5b is a diagram illustrating a film having ITO/ZnO/PBDB-T: IT-M/L-GO: NiO in accordance with one or more embodiments_xInverted OSC of the/Ag structure compared to a control device with a structure of ITO/ZnO/PBDB-T IT-M/L-GO/AgLight intensity of 100mW/cm²Graph of current density-voltage (J-V) characteristics at am1.5g solar spectrum.

Detailed Description

Embodiments of the subject invention include fully mixed GO: NiO in non-aqueous solution_xNanocomposites that can successfully form effective top HT L in inverted OSCs in embodiments, two approaches are considered to achieve thickness spread and uniform top HT L from our new solution processing approach first, embodiments utilize GO-NS and NiO_xHydrogen bonding between NPs will NiO_xNP modification to GO NS to achieve thickness expanded HT L second, embodiment utilizes the degree of GO oxidation to critically control GO: NiO_xTo achieve a uniform HT L film as a result, embodiments of the subject invention show optimized GO NiO_xNanocomposite membranes show about 15 times better conductivity than GO membranes the long-standing concern of GO HT L, which is typically too thin with a thickness of only about 2nm, is addressed by expanding the thickness by a factor of about 16 to as thick as 32nm_xThe electric conductivity and the electronic blocking capability of the nano composite film are enhanced, and the optimized material based on GO: NiO_xShort-circuit current density (J) in inverted OSC of top HT L_SC) Fill Factor (FF) and Power Conversion Efficiency (PCE) are all improved. Overall, by using this GO: NiO compared to a GO-only based OSC_xHT L achieved a 15% improvement in Power Conversion Efficiency (PCE). Again, this GO: NiO_xThe nanocomposite HT L was successfully applied to improve the performance of both fullerenic and non-fullerenic OSCs, which contributes not only to robust and practical applications in organic opto-electronic devices, but also to robust and practical applications in other emerging solution-processed optoelectronics (devices).

By strategically controlling the hydroxyl groups of GO NS and attachment to NiO_xOf a hydroxyl group of a coordinatively unsaturated metal atom ofThe NiO can be converted into NiO through the mutual action of hydrogen bonds_xModification of NPs onto GO NS surfaces to form hybrid GO: NiO_xA nanocomposite material. Ethanol dispersible NiO synthesized by solvothermal method_xNP, and synthesis of GO-NS. by a modified Hummers method-in particular, this GO NS exhibits a low degree of oxidation and is denoted L-GO.

FIG. 1a shows NiO in ethanol according to an exemplary embodiment_xNP, L-GO NS, H-GO NS and L-GO NiO_xAnd H-GO: NiO_xPhotographs of the nanocomposites, and FIGS. 2a-2d show L-GO, NiO_xNP-modified L-GO, H-GO, NiO_xAnd L-GO NiO_xTEM image and SEM image of (a). In particular, NiO_xNP and L-GO NS solutions are shown in FIGS. 1a-I and 1a-II, respectively, NiO has been investigated by Transmission Electron Microscopy (TEM) as shown in FIGS. 2a and 2b_xModification of NP at L-GO NS referring to FIGS. 2a-2d, L-GO NS exhibits a size of approximately 1-2 μm_xThe TEM image results after NP modification are shown in figure 2 b. Black dots being NiO_xThe nano-sheet structure of NP, L-GO is outlined by NiO_xThe modification of the NP is clearly outlined. Thus, by adding in GO NS and NiO_xBy introducing hydrogen bonding between NPs, embodiments of the subject invention successfully achieve well-mixed L-GO: NiO_xNanocomposite materials that can form high quality (dense and well covered) films (SEM images as shown in fig. 2 d), and suitable HT L film application potential as described below.

The degree of oxidation of GO was demonstrated to achieve GO: NiO for high quality membranes_xUnlike the synthesis process for low oxidation GO (i.e., L-GO), an additional pre-oxidation process is introduced during synthesis that produces high oxidation GO (H-GO)_xThe formation of nanocomposite films is highly dependent on the degree of oxidation of GO (as described below). GO can be considered as graphene NS functionalized with carboxyl, hydroxyl and epoxy groups. Due to the breakdown of the conjugated structure, graphene NS can transition from conductive to nearly insulating. Meanwhile, the energy band gap exists in GO,this is different from zero band gap graphene the degree of oxidation of GO depends on the density of functional groups formed on the substrate (basal panel) here, synthetic GO with different degrees of oxidation dispersed in ethanol shows different appearance as shown in fig. 1aII and a-III L-GO solution shows a yellow-like color, while H-GO solution shows a slightly red-like color.

FIG. 1b shows C1s XPS spectra for L-GO and H-GO according to an exemplary embodiment FIG. 1C shows FTIR spectra for L-GO and H-GO according to an exemplary embodiment (at 1625 cm)^-1See figure 1 b. XPS spectra of both L-GO and H-GO show C-C (284.8eV), C-O (286.8eV) and C ═ O (288.6eV) species with reference to figure 1b, XPS spectra of both L-GO and H-GO show significant differences however, the peak amplitudes of both GO in L-GO spectra the C-C peak is significantly higher than the C-O peak, while in the case of H-GO the opposite situation is seen, the ratio between C-C, C-O and C ═ O for L-GO is 1:0.54:0.15, while for H-GO the ratio is 1:1.32: 0.11. the higher ratio of C-O and C ═ O to C-C indicates a higher degree of oxidation of H-GO, this being true mainly due to the higher concentration of C-O species, the higher concentration of C-O species has also been identified using carbon based transformation (FTIR) to show the higher degree of oxidation in the FTIR spectrum of H-GO as shown in figure 1C 1625cm^-1Is normalized by sp²Asymmetric vibratory stretching of hybridized C ═ C. This spectrum identified the presence of carboxyl groups (at 1731 cm)^-1C ═ O elongation at 1400cm^-1O-H bend at COOH), tertiary hydroxyl group (at 1227cm^-1And at 1075cm^-1C-O) and epoxy groups (at 1260 cm)^-1C-O of (C-O). 1227cm^-1And 1075cm^-1The relatively strong peaks indicate a higher density of hydroxyl groups of H-GO. Both XPS and FTIR spectra indicate that the higher degree of oxidation of H-GO is mainly due to the higher hydroxyl group density.

For the case of H-GO as shown in fig. 2c, the drastic hydrogen bonding induces shrinkage of the modified H-GO NS due to the high density of hydroxyl groups on the GO NS. NiO_xNP-modified H-GO NS shrink into aggregates several hundred nanometers in size. As shown in the figure1a-V, these aggregates were not stably dispersed in ethanol and precipitated at the bottom of the vial. By spin coating the suspension, large H-GO: NiO_xThis poorly formed film is therefore not as good as HT L in inverted OSC because poor coverage will lead to current leakage and severe surface recombination_xNP-modified L-GO NS can form high quality nanocomposite films.

FIGS. 3a-3c show a solar cell (ITO/ZnO/PTB7-Th: PC, respectively, according to an exemplary embodiment₇₁BM/HT L/Ag), solar cell (ITO/ZnO/PBDB-T: ITIC/HT L/Ag), solar cell (ITO/ZnO/PBDB-T: IT-M/HT L/Ag), solar cell as a photovoltaic device comprising a glass layer, an Indium Tin Oxide (ITO) layer on the glass layer, a zinc oxide (ZnO) layer on the ITO layer, an organic active layer on the ZnO layer, and a hole transport layer (HT L) on the organic active layer, and an Ag anode electrode on HT L, the ITO layer and the ZnO layer serving as a cathode electrode, the organic active layer comprising PTB7-Th: PC/HT L/Ag)₇₁At least one of BM, PBDB-T: ITIC and PBDB-T: IT-M. The Ag anode electrode is configured to transfer holes h⁺And the ITO layer is configured to transfer electrons e^-。

HT L comprises GO: NiO_xNanocomposite material in order to extend the thickness of HT L and achieve a uniform HT L the GO of HT L comprises graphene oxide nanosheet structure (GO NS) having a low degree of oxidation such that the C-C peak of the GO NS is higher than the C-O peak.

The subject invention includes, but is not limited to, the following exemplary embodiments.

Embodiment 1. preparation of GO: NiO based materials for optoelectronic devices_xMembrane (GO: NiO)_xA nanocomposite film), the method comprising:

preparing a Graphene Oxide (GO) solution in a first alcohol solvent by oxidation of graphite;

preparation of nickel oxide (NiO) in a second glycol solvent by a solvothermal method_x) A solution;

by mixing GO solution with NiO_xSolution blending to make NiO_xNanoparticles decorated onto GO Nanosheet Structure (NS) to obtain GO: NiO_xA nanocomposite solution; and

by using GO: NiO_xNanocomposite solution to form GO: NiO_xA nanocomposite film.

Embodiment 2 the method of embodiment 1, wherein GO is a carbon-based material bound to a functional group.

Embodiment 3 the method of embodiment 2, wherein the functional group comprises one or more of a hydroxyl, carboxyl, epoxy, amino, and sulfonic acid group.

Embodiment 4 the process of any of embodiments 1-3 wherein the second glycol solvent of the solvothermal process comprises water, ethanol, methanol, isopropanol, ethylene glycol, glycerol, or a mixture of any thereof.

Embodiment 5 the process of any of embodiments 1 to 4 wherein NiO_xIs a composite material consisting essentially of/comprising/consisting of: NiO and Ni selected from nickel oxide (Ni)₂O₃) Nickel oxyhydroxide (NiOOH) and nickel hydroxide Ni (OH)₂Other species of (1).

Embodiment 6 the process of any of embodiments 1 to 5 wherein NiO_xIs non-stoichiometric or exhibits typical non-stoichiometric properties, and may have an atomic ratio between nickel and oxygen that deviates from 1:1.

Embodiment 7 the process of any of embodiments 1 to 6 wherein NiO_xHaving typical p-type semiconductor properties.

Embodiment 8 the method of any of embodiments 1 to 7, wherein the first alcohol solvent for the GO solution comprises methanol (CH)₃OH), ethanol (C)₂H₅OH), propanol (C)₃H₇OH), butanol (C)₄H₉OH) or a mixture of any of them.

Embodiment 9 the process of any of embodiments 1 to 8 wherein there is used NiO_xThe second glycol solvent of the solution comprises methanol (CH)₃OH), ethanol (C)₂H₅OH), propanol (C)₃H₇OH), butanol (C)₄H₉OH) or a mixture of any of them.

Embodiment 10 the method of any of embodiments 1 to 9, wherein forming is based on GO: NiO_xThe nanocomposite film further includes a GO: NiO based film obtained by using one or more of casting, spin coating, doctor blading, screen printing, ink jet printing, pad printing, and roll-to-roll techniques_xA hole transport layer of a nanocomposite.

Embodiment 11 the method of any of embodiments 1-10, wherein the optoelectronic device is a device selected from the group consisting of a solar cell, a phototransistor, a photomultiplier, a photoresistor, a light emitting diode, a laser diode, and a sensor.

Embodiment 12 a photovoltaic device, comprising:

a first electrode layer;

an organic active layer disposed on the first electrode layer;

disposed on the organic active layer and including GO: NiO_xA hole transport layer of a nanocomposite; and

a second electrode layer disposed on the hole transport layer.

Embodiment 13 optoelectronic device of embodiment 12 wherein GO: NiO_xThe nanocomposite comprises nickel oxide Nanoparticles (NiO)_xNP) and graphene oxide nanoplatelet structure (GO NS).

Embodiment 14 the photovoltaic device of embodiment 13, wherein GO NS has a low degree of oxidation with a higher C-C peak than a C-O peak.

Embodiment 15 the optoelectronic device of any of embodiments 13 to 14, wherein NiO_xNP and GO NS are coupled to each other by hydrogen bonds.

Embodiment 16 the optoelectronic device of any one of embodiments 12 to 15, wherein the hole transport layer has a thickness in a range from 17nm to 32 nm.

Embodiment 17 an optoelectronic device according to any of embodiments 12 to 16, wherein the first electrode layer comprises a layer of Indium Tin Oxide (ITO) and a layer of zinc oxide (ZnO).

Embodiment 18 an optoelectronic device according to any of embodiments 12 to 17, wherein the second electrode layer comprises an Ag anode electrode.

Embodiment 19 the optoelectronic device of any of embodiments 17 to 18, further comprising a glass layer disposed on a bottom surface of the ITO layer.

Embodiment 20 an optoelectronic device according to any of embodiments 12 to 19, wherein the organic active layer comprises PTB7-Th PC₇₁At least one of BM, PBDB-T: ITIC/HT L and PBDB-T: ITIC.

In any of the above embodiments, the first alcohol solvent or the second alcohol solvent may comprise an alkanol having 1 to 10 carbon atoms.

In any of the above embodiments, the thickness of the hole transport layer may be in the range of 8nm to 64nm, 12nm to 48nm, or 17nm to 32 nm.

In one embodiment of the invention, the invention relates to GO: NiO_xUse of a nanocomposite in HT L.

A better understanding of the present invention, as well as of many of its advantages, may be obtained from the following examples which are given by way of illustration. The following examples illustrate some of the methods, applications, embodiments and variations of the present invention. They should not, of course, be construed as limiting the invention. Many variations and modifications may be made with respect to the present invention.

Examples

Conventionally, sp for graphene due to functional groups (including epoxy/hydroxyl groups on basal planes and carboxylic acid groups at the edges)²The original GO also shows such thickness-dependent performance, as demonstrated by the example of L-GO, short circuit current density due to poor conductivity of L-GO (J) at a thickness of 9.9nm (J)_SC) Very small, the device exhibits almost zero current, only until the thickness of L-GO is reduced to 4.1nm, J_SCBegins to increase to about 10mAcm^-2The optimized L-GO thickness is very thin, with a value of 2.1nm, and the optimized PCE of 8.80%. As the thickness is further reduced, due to the open circuit voltage (V)_OC) ReduceOur results therefore demonstrate the thickness issue of GO being too thin/sensitive for OSC applications.

To address the issue of very thin GO thicknesses, embodiments of the subject invention form L-GO and NiO_x(0.5:5mg mL^-1) Nanocomposite films prepared by the methods described in the previous sections the conductivity enhancement has been investigated by contact mode conductive atomic force microscopy (c-AFM). L-GO, L-GO: NiO_xAnd NiO_xIs fixed at about 20nm and the current-voltage (I-V) curve is measured by c-AFM at a bias of-2.0V for L-GO, L-GO: NiO_x、NiO_xThe measured currents were 0.06nA, 3.06nA, 10.35nA, respectively. With stoichiometric NiO (one having 10)^-13S cm^-1Wide band gap semiconductors of low intrinsic conductivity) due to the introduction of Ni³⁺Induced Ni vacancies, our non-stoichiometric NiO_xHas much higher conductivity (5.10 × 10 of conductivity)^-4S cm^-1). Therefore, NiO is added_xConductivity increased to 1.38 × 10 after modification at L-GO NS^-4S cm^-1It showed a difference from the conductivity (9.54 × 10)^-6S cm^-1) Compared with the original L-GO, the increase is about 14 times.

The following are examples illustrating procedures for practicing the present invention. These examples should not be construed as limiting.

Example 1

By adding NiO in ethanol_xPreparation of the novel GO: NiO by NP modification onto GO NS_xA nanocomposite dispersion. 1g of graphite and 0.5g of sodium nitrate (NaNO)₃) With concentrated sulfuric acid (H)₂SO₄98%, 25m L) was stirred under ice bath then 3g potassium permanganate (KMnO) was slowly added to the mixture₄) After stirring for 2H under ice bath, the reaction mixture was heated to 35 ℃ for 1H with 200m L Deionized (DI) water and 10m L concentrated H₂SO₄Mixture ofDesizing, finally, 10m L hydrogen peroxide (H) was added₂

O

_2,30%) to form L-GO dispersion the dispersion was centrifuged at 6000rpm for 10min and the precipitate was washed 3 times with DI water and ethanol respectively finally the precipitate was dispersed in ethanol to obtain L-GO. in ethanol for H-GO synthesis using 7.5ml of concentrated H₂SO₄Sonication of 1g graphite for 8H pre-oxidized graphite was washed with water and dried, followed by the same reaction procedure as L-GO to give H-GO. in ethanol 0.13g nickel acetylacetonate (Ni (acac)₂) And 14m L t-butanol at 700rpm for 30min and transferred to a 20m L Teflon-lined autoclave (Teflon @.) after heat treatment at 220 ℃ in a muffle furnace for 20h_xNP is a basic amino acid. NiO is mixed_xNP at 5:0.5mg m L^-1Is modified on GO NS to form GO: NiO_xA nanocomposite dispersion. The dispersion can be spin coated onto a substrate to form GO: NiO_xA nanocomposite film.

Example 2

Will have a cross section of 15 Ω sq^-1The sheet resistance ITO coated glass substrate of (1) was cleaned and then subjected to UVO treatment for 15 min. 44mg of zinc acetate dihydrate (Zn (OAc)₂·2H₂O) and 12 μ L ethanolamine were dissolved in 2m L Isopropanol (iPA). the solution was spin coated onto clean ITO at 3000rpm and then annealed at 200 ℃ for 1h to form ZnO electron transport layer (ET L). Polymer donor PTB7-Th and fullerene acceptor PC₇₁BM from Solarmer Co., L td. PTB7-Th PC to which 3% by volume of 1, 8-Diiodooctane (DIO) was added₇₁BM (10: 15mg m L in chlorobenzene)^-1) Spin-coated on ZnO at 2000rpm by diluting 150. mu. L (fluoring) to spinning PTB7-Th PC₇₁L-GO (0.5mg m L) on BM active layer to remove DIO^-1)、L-GO:NiO_x(0.5:5mg mL^-1) And NiO_x(5mg mL^-1) Spin-coated onto the active layer. Finally, Ag (100nm) was thermally evaporated through a shadow mask as a top cathode, which defined a device area of 0.06cm². By using the same as the figureITO/ZnO/PTB7-Th PC shown in 3a₇₁Inverted structure fabrication of BM/HT L/Ag based on PTB7-Th PC₇₁The OSC of the BM and tested as shown in Table 1.

TABLE 1 PC with ITO/ZnO/PTB7-Th₇₁A summary of the performance of OSCs for the structure of BM/HT L/Ag

Example 3

The device fabrication process was the same as in example 2, using PBDB-T: ITIC (10: 10mgm L in chlorobenzene)^-1Addition of 0.5% DIO) instead of PTB7-Th PC₇₁Polymer donor PBDB-T and non-fullerene acceptor ITIC purchased from Solarmer co., L td. dio was removed by annealing the active layer at 160 ℃ for 30min OSC-an OSC based on PBDB-T: ITIC was made by using an inverted structure of ITO/ZnO/PBDB-T: ITIC/HT L/Ag as shown in fig. 3b and tested as shown in table 2.

TABLE 2 summary of OSC Performance for structures with ITO/ZnO/PBDB-T ITIC/HT L/Ag

Example 4

The device fabrication process was the same as in example 2, using PBDB-T: IT-M (10: 10mgm L in chlorobenzene; see FIGS^-1Addition of 1% DIO) instead of PTB7-Th PC₇₁The PBDB-T: IT-M based OSC was fabricated by using an inverted structure of ITO/ZnO/PBDB-T: IT-M/HT L/Ag as shown in FIG. 3c and tested as shown in Table 3.

TABLE 3 summary of the Performance of OSC devices having a structure of ITO/ZnO/PBDB-T IT-M/HT L/Ag

FIG. 4a shows NiO based on L-GO and L-GO_xRepresentative J-V curves of inverted OSCs for nanocomposites, whose performance is summarized in example 1 As discussed above, L-GO-based devices show an optimized average PCE of 8.80%, average J_SCIs 18.39mA cm^-2Average V_OCIt was 0.78V and the average FF was 0.614. Based on NiO_xShows poor V due to mismatched WF values_OC. NiO is mixed_xAfter decorating on L-GO, the average PCE increased significantly to 9.73% (optimal PCE was 9.93%), and the average J_SCIncreased to 19.16mA cm^-2FF increased to 0.651. J. the design is a square_SCThe increase in NiO was attributed to L-GO: NiO compared to bare GO_xThe electrical conductivity of the nanocomposite is increased.

FIG. 4b illustrates NiO by using L-GO_xNano composite material (by adopting GO-NS and NiO strategically_xHydrogen bond formation between NPs) can significantly increase the thickness of GO when GO is used as HT L, the thickness requirements are stringent and any small thickness variation can significantly reduce performance, for example, when the thickness is increased from 2.1nm to 3.4nm in 1.3nm increments alone, the average PCE drops to 4.23%, less than half of the optimized average PCE (8.80%)_xThe nano composite material replacing L-GO can obviously reduce the thickness dependence sensitivity when L-GO: NiO_xThe device showed an optimized average PCE of 9.73% for a nanocomposite thickness of 21 nm-when the thickness was increased to 32nm (over 15 times the bare L-GO thickness), the average PCE was 9.10%, which is still superior to the original L-GO case.

FIGS. 5a and 5b illustrate our newly developed L-GO: NiO_xNanocomposite HT L can also serve as an effective HT L for a non-fullerene OSC by using a compound named poly [ (2,6- (4, 8-bis (5- (2-ethylhexyl) thiophen-2-yl) benzo [1,2-b:4,5-b']Bithiophene) -co- (1, 3-bis (5-thiophen-2-yl) -5, 7-bis (2-ethylhexyl) -benzo [1,2-c:4,5-c']Dithiophene-4, 8-diones)](PBDB-T) Polymer Donor and non-Fullerene Acceptor 3, 9-bis (2-methylene- (3- (1, 1-dicyanomethylene) -indanone) -5,5,11, 11-tetrakis (4-hexylphenyl) -dithieno [2,3-d:2',3' -d ']-s-indaceno [1,2-b:5,6-b']Combinations of-dithiophenes (ITICs) based on L-GO: NiO_xThe average PCE of a nanocomposite device can be up to 10.68% (with an optimal PCE of 11.12%). Based on GO: NiO by using a combination of PBDB-T and methyl modulated ITIC (IT-M)_xThe average PCE of a nanocomposite device can reach 11.45% (with an optimal PCE of 12.13%). Weak energy loss during charge transfer of PBDB-T IT-M results in higher V than PBDB-T IT-M based devices_OC(about 0.91V.) optimized photovoltaic parameters and representative J-V characteristics are summarized in example 2 and example 3, respectively in the PBDB-T: ITIC System, L-GO: NiO_xThe nanocomposite OSC showed a higher average PCE (10.68%) compared to the average PCE of GO OSC (9.28%). The PCE improvement of 15.0% is primarily attributed to J_SCAnd an increase in both FF. Similarly, in the PBDB-T: IT-M system, based on GO: NiO_xThe average PCE of the nanocomposite devices showed a 14.4% improvement (from 10.01% to 11.45%) over the GO-based devices. J. the design is a square_SCImprovement (from 17.07mA cm^-2To 17.81mA cm^-2) And improvement in FF (from 0.644 to 0.706) contributes to the PCE improvement.

It is understood that the examples and embodiments described herein are for illustrative purposes only and that various modifications or changes in light thereof will be suggested to persons skilled in the art and are to be included within the spirit and purview of this application and scope of the appended claims. Furthermore, any elements or limitations of any invention or embodiment thereof disclosed herein can be combined with any and/or all other elements or limitations (alone or in any combination) or any other invention or embodiment thereof disclosed herein, and all such combinations are contemplated with the scope of the invention, but are not limited thereto.

Claims

1. Preparation of GO: NiO-based materials for optoelectronic devices_xA method of forming a film of a nanocomposite, the method comprising:

preparing a graphene oxide GO solution in a first alcohol solvent by oxidation of graphite;

preparation of nickel oxide NiO in a second alcohol solvent by a solvothermal method_xA solution;

by mixing the GO solution and the NiO_xSolution blending to make NiO_xNanoparticles are decorated onto the GO nano-sheet structure NS to obtain GO: NiO_xA nanocomposite solution; and

NiO by using the GO_xNanocomposite solution to form GO: NiO_xA nanocomposite film having a plurality of pores,

where x is a positive number.

2. The method of claim 1, wherein the first step is carried out in a single step,

wherein the GO is a carbon-based material bound to a functional group; or

Wherein the GO is a carbon-based material bonded with functional groups comprising one or more of hydroxyl, carboxyl, epoxy, amino, and sulfonic acid groups; or

Wherein the second glycol solvent of the solvothermal process comprises water, ethanol, methanol, isopropanol, ethylene glycol, glycerol, or a mixture of any thereof; or

Wherein the NiO_xIs a composite material comprising or consisting of: NiO and Ni₂O₃Other species of nickel oxyhydroxide and nickel hydroxide; or

Wherein the NiO_xIs non-stoichiometric; or

Wherein the NiO_xHas typical p-type semiconductor properties; or

Wherein the first alcohol solvent for the GO solution comprises an alkanol having 1-10 carbon atoms, or a mixture of methanol, ethanol, propanol, butanol, or any thereof; or

Wherein for the NiO_xThe second alcohol solvent of the solution comprises an alkanol having 1-10 carbon atoms, or a mixture of methanol, ethanol, propanol, butanol, or any of them; or

Wherein the GO: NiO is formed_xThe nanocomposite film further includes obtaining the GO: NiO based by using one or more of casting, spin coating, doctor-blading, screen printing, ink jet printing, gravure pad printing, and roll-to-roll techniques_xNano meterA hole transport layer of a composite material; or

Wherein the optoelectronic device is a device selected from the group consisting of: solar cells, phototransistors, photomultipliers, photoresistors, light emitting diodes, laser diodes, and sensors.

3. An optoelectronic device, comprising:

a first electrode layer;

an organic active layer disposed on the first electrode layer;

NiO disposed on the organic active layer and comprising GO_xA hole transport layer of a nanocomposite; and

a second electrode layer disposed on the hole transport layer,

where x is a positive number.

4. The optoelectronic device of claim 3, wherein the GO: NiO_xThe nanocomposite comprises nickel oxide nanoparticles NiO_xNP and graphene oxide nanosheet structure GO NS.

5. The optoelectronic device of claim 4, wherein the GO NS has a degree of oxidation with a C-C peak higher than a C-O peak.

6. The optoelectronic device of claim 5, wherein the NiO_xNP and said GO NS are coupled to each other by hydrogen bonds.

7. An optoelectronic device as claimed in claim 6,

wherein the hole transport layer has a thickness in a range of 8nm to 64nm, 12nm to 48nm, or 17nm to 32 nm; or

Wherein the first electrode layer comprises an Indium Tin Oxide (ITO) layer and a zinc oxide layer.

8. The photovoltaic device of claim 7, wherein the second electrode layer comprises an Ag anode electrode.

9. The photovoltaic device of claim 8, further comprising a glass layer disposed on a bottom surface of the ITO layer.

10. An optoelectronic device according to claim 9, wherein the organic active layer comprises PTB7-Th PC₇₁At least one of BM, PBDB-T: ITIC/HT L and PBDB-T: ITIC.