A thin-film optoelectronic device with a composite semi-transparent top electrode and its fabrication method

Abstract

This invention discloses a thin-film optoelectronic device with a composite semi-transparent top electrode and its fabrication method. Belonging to the field of new material solar cells, stability is a significant factor hindering the industrialization of thin-film optoelectronic devices. Mainstream cells use metal back electrodes, which suffer from metal diffusion and chemical corrosion, leading to decreased stability. Cells using inorganic electrodes have relatively low efficiency due to sheet resistance issues. Therefore, to address this problem, a hole transport layer is first prepared, followed by an organic-inorganic hybrid semiconductor thin film, then an electron transport layer, followed by an interface modification layer, and finally, a composite semi-transparent top electrode (ITO / ITO-X / AZO / AZO-X, where X = Cu or Ag) is prepared by in-situ continuous deposition. This in-situ prepared composite semi-transparent top electrode is fabricated using an in-situ continuous composite sputtering method, forming an inorganic-metal / inorganic hybrid-inorganic thin film composite semi-transparent top electrode.

Description

Technical Field

[0001] This invention relates to the field of new material solar cells, specifically to a thin-film optoelectronic device with a composite semi-transparent top electrode and its preparation method. Background Technology

[0002] The band gap of perovskite materials is tunable within the range of 1.2-2.3 eV. Therefore, depending on the spectral absorption range, semi-transparent electrodes can be used to fabricate semi-transparent thin-film optoelectronic devices, replacing traditional metal all-electrodes. Although the photoelectric conversion efficiency of semi-transparent thin-film optoelectronic devices is currently lower than that of traditional non-transparent thin-film optoelectronic devices, semi-transparent perovskite solar cells have broad application prospects, including tandem solar cells, building-integrated photovoltaics (BIPV), and wearable electronic devices. Among these applications, perovskite / silicon-based tandem solar cells are considered the next generation of photovoltaic technology, aiming to break the efficiency barrier of crystalline silicon solar cells and continuously reduce manufacturing costs. In addition to the high-efficiency application of near-infrared semi-transparent thin-film optoelectronic devices in tandem solar cells, colored perovskite cells can serve as power-generating windows in buildings, displays for self-powered electronic devices, and roofs for solar-powered cars. The efficiency and optical performance of semi-transparent thin-film optoelectronic devices are often mutually restrictive, and their optical performance refers to average visible light transmittance, average near-infrared light transmittance, and color rendering index. The performance of semi-transparent thin-film optoelectronic devices is currently improved mainly through the following aspects: the perovskite absorption layer, the electron transport layer, and the semi-transparent electrode. First, the bandgap of perovskite materials can be easily altered by simply adjusting the elemental ratios and composition, a crucial step in manufacturing colored and wide-bandgap perovskite solar cells. In addition to component engineering, using thinner perovskite absorber layers to fabricate semi-transparent thin-film optoelectronic devices and further optimizing their structure and process design can improve light transmittance in the near-infrared region. Second, semi-transparent thin-film optoelectronic devices achieve high efficiency regardless of whether they are illuminated from the front or back. Therefore, selecting electron and hole transport layer materials with thinner and wider bandgap widths to reduce parasitic absorption is essential for their better application in semi-transparent perovskite solar cells. Finally, the semi-transparent electrode is the biggest structural difference compared to non-semi-transparent perovskite solar cells; therefore, balancing the transmittance and conductivity of the semi-transparent electrode is key to achieving high efficiency, stability, and low cost in semi-transparent thin-film optoelectronic devices.

[0003] Here, we propose a thin-film optoelectronic device with a composite semi-transparent top electrode and its fabrication method. The composite semi-transparent top electrode, fabricated by in-situ composite sputtering of an inorganic-metal / inorganic hybrid-inorganic thin film, solves both the stability problem caused by metal electrodes and the low efficiency problem of inorganic electrodes, thus facilitating the industrialization of thin-film optoelectronic devices. Summary of the Invention

[0004] To address the problems existing in the prior art, this application provides a thin-film optoelectronic device with a composite semi-transparent top electrode and its fabrication method. The composite semi-transparent top electrode, fabricated by in-situ composite sputtering of an inorganic-metal / inorganic hybrid-inorganic thin film, solves both the stability problem caused by metal electrodes and the low efficiency problem of inorganic electrodes.

[0005] To achieve the above objectives, according to one aspect of the present invention, a thin-film optoelectronic device with a composite semi-transparent top electrode is provided, wherein the solar cell has a hole transport layer, and then a calcium organic-inorganic hybrid semiconductor thin film ABX3, where A = CH3NH3, is prepared. + or CH(NH2)2 + or Cs + Or a mixture of the three; X = Cl - ,Br - I - The preparation of the mixture thereof, followed by deposition of an electron transport layer C60, then deposition of an interface modification layer (including LiF or BCP or TiOx or SnOx), and finally deposition of an in-situ prepared composite semi-transparent top electrode (ITO / ITO-X / AZO / AZO-X, X = Cu or Ag).

[0006] The conductive substrate is a TCO substrate;

[0007] The composite semi-transparent top electrode is an in-situ composite sputtered inorganic-metal / inorganic hybrid-inorganic thin film composite semi-transparent top electrode with a structure of ITO / ITO-X / AZO / AZO-X, where X = Cu or Ag. From bottom to top, it consists of an ITO electrode layer, an ITO-X composite transition layer, an AZO layer, and an AZO-X composite collection layer. This solves the stability problem caused by metal electrodes and also solves the problem of low efficiency of inorganic electrodes.

[0008] The modification layer is an organic or inorganic material that has the ability to adjust the work function and energy level position of the back electrode;

[0009] The calcium organic-inorganic hybrid semiconductor thin film is A=CH3NH 3+ Or CH(NH2) 2+ or Cs + Or a mixture of the three; B = Pb or Sn; X = Cl - ,Br - I - Or a mixture thereof.

[0010] Preferably, the composite semi-transparent top electrode prepared in situ is characterized in that: the thickness of the ITO / ITO-X / AZO / AZO-X, where X = Cu or Ag, is 100-200 nm, 0-10 nm, 100-200 nm, and 0-10 nm, respectively.

[0011] Preferably, in the thin-film optoelectronic device with a composite semi-transparent top electrode prepared in situ, the sheet resistance of the composite top electrode is ≤10Ω / □;

[0012] Preferably, in the solar cell, the electron transport layer is a fullerene thin film, and the fullerene thin film is C60;

[0013] The above preparation method includes the following steps:

[0014] Step (1) Preparation of calcium organic-inorganic hybrid semiconductor thin film by solution method, wherein the calcium organic-inorganic hybrid semiconductor thin film is ABX3, A=CH3NH3 + or CH(NH2)2 + or Cs + Or a mixture of the three; X = Cl - ,Br - I - The preparation of the perovskite precursor solution or a mixture thereof involves coating the prepared perovskite precursor solution onto the hole transport layer and then annealing it on a hot plate.

[0015] Step (2) Preparation of the electron transport layer: C60 powder was deposited onto a calcium organic-inorganic hybrid semiconductor thin film by vacuum evaporation, with a vacuum degree of 1×10⁻⁶. -5 -5×10 -4 Pa, with a thickness of 20-80 nm;

[0016] Step (3) Preparation of the interface modification layer: LiF or BCP powder is deposited onto a C60 thin film by vacuum evaporation, achieving a porosity of 1×10⁻⁶. -5 -5×10 -4 Pa, with a thickness of 5-20 nm; TiOx and other precursor solutions are spin-coated onto C60 thin films, and then annealed on a hot plate;

[0017] Step (4) Place the substrate with the deposited interface modification layer into the magnetron sputtering chamber. First, turn on the ITO sputtering power supply to sputter and prepare a single ITO film with a thickness of 100-200 nm. Then, turn on the metal sputtering power supply to perform co-sputtering of ITO and metal with a co-sputtering thickness of 5-10 nm. Then, turn off the ITO and metal sputtering power supplies and switch to the AZO sputtering power supply to prepare a single AZO film. Then, turn on the metal sputtering power supply to perform co-sputtering of AZO and metal with a co-sputtering thickness of 5-10 nm. The ITO sputtering method is DC pulse sputtering, the working gas is Ar / O2, the oxygen partial pressure is 0-3%, the sputtering rate is controlled at 3-7 nm / min, the sputtering working gas pressure is 0.2-0.8 Pa, and the sputtering vacuum degree is controlled at ≤4×10 -3Pa; ITO-X transition layer, using dual-target co-sputtering. ITO is sputtered using a direct pulse method, and the metal is sputtered using a direct pulse method. The sputtering rate for both is 3-7 nm / min, and the working gas is Ar; the sputtering vacuum is controlled at ≤4×10⁻⁶. -3 Pa; the sputtering method for single AZO is DC pulse sputtering, the working gas is Ar / O2, the oxygen partial pressure is 0-3%, the sputtering rate is controlled at 3-7 nm / min, the sputtering working gas pressure is 0.2-0.8 Pa, and the sputtering vacuum degree is controlled at ≤4×10 Pa. -3 Pa; AZO-X collection layer, using dual-target co-sputtering: AZO and metal are sputtered using a direct pulse method, with sputtering rates of 3-7 nm / min for both, and Ar as the working gas. The single ITO sputtering method uses DC pulse sputtering, with Ar / O2 as the working gas, oxygen partial pressure of 0-3%, sputtering rate controlled at 3-7 nm / min, sputtering working gas pressure of 0.2-0.8 Pa, and sputtering vacuum controlled at ≤4 × 10⁻⁶ Pa. -3 Pa; ITO-X transition layer, using dual-target co-sputtering. ITO is sputtered using a direct pulse method, and the metal is sputtered using a direct pulse method. The sputtering rate for both is 3-7 nm / min, and the working gas is Ar; the sputtering vacuum is controlled at ≤4×10⁻⁶. -3 Pa; the sputtering method for single AZO is DC pulse sputtering, the working gas is Ar / O2, the oxygen partial pressure is 0-3%, the sputtering rate is controlled at 3-7 nm / min, the sputtering working gas pressure is 0.2-0.8 Pa, and the sputtering vacuum degree is controlled at ≤4×10 Pa. -3 Pa; AZO-collection layer, using dual-target co-sputtering method, AZO is sputtered by direct pulse method, metal is sputtered by direct pulse method, sputtering rate of both is 3-7nm / min, working gas is Ar;

[0018] Preferably, in general, the technical concept of the present invention has the following main advantages compared with the prior art:

[0019] This invention utilizes a thin-film optoelectronic device with an in-situ prepared composite semi-transparent top electrode and its preparation method. The composite semi-transparent top electrode is prepared by in-situ composite sputtering, which solves both the stability problem caused by metal electrodes and the low efficiency problem of inorganic electrodes. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of a new structure for thin-film optoelectronic devices;

[0021] Figure 2 The composite semi-transparent top electrode transmits data;

[0022] Figure 3This is Example 1, showing the IV curve of a thin-film optoelectronic device with an in-situ prepared composite semi-transparent top electrode. Detailed Implementation

[0023] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. Furthermore, the technical features involved in the various embodiments of this invention described below can be combined with each other as long as they do not conflict with each other.

[0024] like Figure 1 As shown, the solar cell consists of, from bottom to top, ITO conductive glass 1, hole transport layer, 2, calcium organic-inorganic hybrid semiconductor thin film, 3, electron transport layer, 4, interface modification layer, and 5, composite semi-transparent top electrode.

[0025] ITO conductive glass has a sheet resistance of 5-25Ω and a transmittance of 85-95%.

[0026] The conductive substrate is a TCO substrate;

[0027] Calcium-organic-inorganic hybrid semiconductor thin film ABX3, A=CH3NH3 + or CH(NH2)2 + or Cs + Or a mixture of the three; X = Cl - ,Br - I - Preparation of mixtures thereof, with a thickness of 300nm-800nm;

[0028] The electron transport layer is a fullerene film, and the fullerene film is C60.

[0029] The modification layer is an organic or inorganic material that has the ability to adjust the work function and energy level position of the back electrode;

[0030] The interface modification layer is LiF (thickness 0.5-5nm), BCP (thickness 1-20nm), or TiOX (thickness 5-30nm), which improves the stability of the solar cell.

[0031] The in-situ prepared composite semi-transparent top electrode, ITO / ITO-X / AZO / AZO-X, X=Cu or Ag composite top electrode thickness is 100-200nm, 0-10nm, 100-200nm, 0-10nm respectively, and the sheet resistance of the composite top electrode is ≤10Ω / □.

[0032] Example 1

[0033] Step (1) Select an ITO glass substrate with a sheet resistance of 5-25Ω and a transmittance of 85-95%, and then clean it with detergent, distilled water, ethanol and acetone.

[0034] Step (2) Preparation of the hole transport layer:

[0035] A cleaned substrate coated with an ITO conductive film was placed into a magnetron sputtering chamber, and a multilayer composite NiO thin film was prepared by DC reactive sputtering. The sputtering working gas was Ar / O2, and the sputtering vacuum was controlled at 5 × 10⁻⁶. -4 Pa, the working pressure of dense layer sputtering is controlled between 10 mbar, the Ni target sputtering power is 110 W, and the thickness of single-layer film is controlled at 30 nm; annealing is stabilized at 250℃ for 40 min, and then cooled for use.

[0036] Step (3) Calcium organic-inorganic hybrid semiconductor thin film ABX3, A=CH3NH3 + or CH(NH2)2 + or Cs + Or a mixture of the three; X = Cl - ,Br - I - Preparation of or mixtures thereof;

[0037] PbX2 powder and AX powder in a molar ratio of 1:1 to 1:3 were mixed and dissolved in DMF or DMSO solution, and stirred at 40-70℃ to obtain an ABX3 solution with a Pb molar concentration of 1-2 mol / mL. The above perovskite precursor solution was then prepared on a multilayer NiO hole transport layer by coating or vapor deposition, and then heated at 70-150℃ for 10-120 min.

[0038] Step (4) Fabrication of the electron transport layer:

[0039] C60 powder was deposited onto a calcium-organic-inorganic hybrid semiconductor thin film via vacuum evaporation, achieving a vacuum level of 1×10⁻⁶. -5 -5×10 -4 Pa, with a thickness of 20-80 nm;

[0040] Step (5) Preparation of the LiF / BCP interface modification layer:

[0041] LiF or BCP powder was deposited onto a C60 thin film by vacuum evaporation at a vacuum level of 1×10⁻⁶. -5 -5×10 - 4 Pa, with a thickness of 5-20 nm;

[0042] Step (6) Preparation of the composite semi-transparent electrode:

[0043] The substrate with the interface modification layer deposited is placed in the magnetron sputtering chamber. First, the ITO sputtering power supply is turned on to sputter and prepare a single ITO film with a thickness of 100-200 nm. Then, the metal sputtering power supply is turned on to perform co-sputtering of ITO and metal with a co-sputtering thickness of 5-10 nm. Then, the ITO sputtering power supply and the metal sputtering power supply are turned off, and the AZO sputtering power supply is switched to prepare a single AZO film. Then, the metal sputtering power supply is turned on to perform co-sputtering of AZO and metal with a co-sputtering thickness of 5-10 nm.

[0044] Those skilled in the art will readily understand that the above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A thin-film optoelectronic device with a composite semi-transparent top electrode, characterized in that: The thin-film optoelectronic device consists of, from bottom to top, a conductive substrate, a hole transport layer, a light-absorbing active layer, an electron transport layer, an interface modification layer, and a composite semi-transparent top electrode. The conductive substrate is a TCO substrate; The hole transport layer is a thin film made of P-type semiconductor material; The light-absorbing active layer is an organic-inorganic hybrid semiconductor thin film with an ABX3 structure (A=CH3NH 3+ Or CH(NH2) 2+ or Cs + Or a mixture of the three; B = Pb or Sn; X = Cl - ,Br - I - (or mixtures thereof); The electron transport layer is an N-type semiconductor material; The modification layer is an organic or inorganic material that has the ability to adjust the work function and energy level position of the back electrode; The composite semi-transparent top electrode is a composite semi-transparent top electrode prepared by in-situ composite sputtering of inorganic-metal / inorganic mixed-inorganic thin film. Its structure is ITO / ITO-X / AZO / AZO-X, where X = Cu or Ag. From bottom to top, they are ITO electrode layer, ITO-X composite transition layer, AZO layer, and AZO-X composite collection layer.

2. The thin-film optoelectronic device with a composite semi-transparent top electrode according to claim 1, characterized in that: The conductive substrate has a sheet resistance of 5-25Ω and a transmittance of 85-95%.

3. The thin-film optoelectronic device with a composite semi-transparent top electrode according to claim 1, characterized in that: The hole transport layer has a thickness of 10-50 nm.

4. The thin-film optoelectronic device with a composite semi-transparent top electrode according to claim 1, characterized in that: The thickness of the light-absorbing active layer is 300-1000 nm.

5. The thin-film optoelectronic device with a composite semi-transparent top electrode according to claim 1, characterized in that: The electron transport layer has a thickness of 10-80 nm.

6. The thin-film optoelectronic device with a composite semi-transparent top electrode according to claim 1, characterized in that: The thickness of the modified layer is 5-20 nm.

7. The thin-film optoelectronic device with a composite semi-transparent top electrode according to claim 1, characterized in that: The thicknesses of the ITO / ITO-X / AZO / AZO-X, X = Cu or Ag composite top electrode are 100-200 nm, 0-10 nm, 100-200 nm, and 0-10 nm, respectively.

8. The thin-film optoelectronic device with a composite semi-transparent top electrode according to claim 1, characterized in that: The sheet resistance of the composite top electrode is ≤10Ω / □.

9. A method for fabricating a thin-film optoelectronic device using the composite semi-transparent top electrode according to any one of claims 1 to 8, characterized in that, Includes the following steps: Step (1) Preparation of hole transport layer: The hole transport layer is prepared by physical deposition or chemical deposition, and its thickness is 10-50 nm; Step (2) Preparation of calcium organic-inorganic hybrid semiconductor thin films by solution method: The calcium organic-inorganic hybrid semiconductor thin film ABX3, A=CH3NH 3+ Or CH(NH2) 2+ or Cs + Or a mixture of the three; B = Pb or Sn; X = Cl - ,Br - I - Or a mixture thereof, deposited on the hole transport layer with a thickness of 300-800 nm; Step (3) Fabrication of the electron transport layer: An electron transport layer was deposited onto a calcium-organic-inorganic hybrid semiconductor thin film with a thickness of 10-80 nm. Step (4) Preparation of the interface modification layer: An interface modification layer is deposited onto the electron transport layer, with a thickness of 5-20 nm. Step (5) Preparation of the composite semi-transparent top electrode: The substrate with the interface modification layer deposited is placed in the magnetron sputtering chamber. First, the ITO sputtering power supply is turned on to sputter and prepare a single ITO film with a thickness of 100-200 nm. Then, the metal sputtering power supply is turned on to perform co-sputtering of ITO and metal with a thickness of 5-10 nm. Then, the ITO sputtering power supply and the metal sputtering power supply are turned off, and the AZO sputtering power supply is switched to prepare a single AZO film. Then, the metal sputtering power supply is turned on to perform co-sputtering of AZO and metal with a thickness of 5-10 nm. The single ITO sputtering method employs DC pulse sputtering, using Ar / O2 as the working gas with an oxygen partial pressure of 0-3%, a sputtering rate controlled at 3-7 nm / min, a sputtering working gas pressure of 0.2-0.8 Pa, and a sputtering vacuum degree controlled at ≤4×10⁻⁶. -3 Pa; The ITO-X transition layer is sputtered using a dual-target co-sputtering method. ITO is sputtered using a direct pulse method, and the metal is sputtered using a direct pulse method. The sputtering rate for both is 3-7 nm / min, and the working gas is Ar. The sputtering vacuum degree is controlled at ≤4×10 -3 Pa; The single AZO sputtering method employs DC pulse sputtering, using Ar / O2 as the working gas with an oxygen partial pressure of 0-3%, a sputtering rate controlled at 3-7 nm / min, a sputtering working gas pressure of 0.2-0.8 Pa, and a sputtering vacuum degree controlled at ≤4×10⁻⁶. -3 Pa; The AZO-X collection layer is constructed using a dual-target co-sputtering method. AZO is sputtered using a direct pulse method, and the metal is sputtered using a direct pulse method. The sputtering rate for both is 3-7 nm / min, and the working gas is Ar.

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