Semiconductor photovoltaic material carrier non-radiative recombination rate monitoring method

Abstract

The invention belongs to the field of semiconductor photovoltaic materials and devices, and discloses a method for monitoring the non-radiative recombination rate of carriers of a semiconductor photovoltaic material. The method comprises the following steps: testing a semiconductor material by using a transient absorption spectrum, then carrying out life fitting on a deep bound state carrier absorption signal in a short wave region, monitoring the non-radiative recombination rate caused by defects in the material according to the life length, and obtaining the bulk phase carrier recombination information of the material. The monitoring method has the remarkable advantages of simplicity in operation and easiness in analysis, has good compatibility with various semiconductor preparation processes, can meet the monitoring requirements of different semiconductor photovoltaic materials, and is suitable for application and research in various environments.

Description

Technical Field

[0001] The present invention belongs to the field of semiconductor photovoltaic materials and devices, and relates to a method for monitoring the non-radiative recombination rate of carriers in semiconductor photovoltaic materials. Background Art

[0002] With the rapid development of society and the continuous advancement of science and technology, humanity's demand for energy continues to rise. However, with the increasing depletion of traditional fossil fuels, the development of new renewable energy sources has become an urgent task. Solar energy, due to its inexhaustible, clean, and pollution-free nature, is considered one of the most promising renewable energy sources. Photovoltaic power generation is currently the most important and promising form of solar energy utilization.

[0003] In recent years, researchers have been actively searching for and developing new solar photovoltaic materials with low cost and environmental friendliness. For example, the V-VI binary semiconductor antimony selenide sulfide (Sb2(S,Se)3) has abundant reserves of its constituent elements, diverse preparation processes, adjustable band gap (1.1-1.7eV), wide spectral response range, and high light absorption coefficient (10 5 cm -1 ) and high carrier mobility. In recent years, it has received widespread attention and research as a new type of thin-film solar cell light-absorbing layer material. Adequately obtaining the bulk carrier recombination information of the material is a prerequisite for the efficient application of semiconductor materials such as Sb2(S,Se)3 in the photovoltaic field. When there are defects or impurity energy levels inside the material, carriers will undergo non-radiative recombination in the defects, reducing the utilization rate of photogenerated carriers and affecting the photoelectric properties of the material. Therefore, the ability to efficiently and conveniently monitor the non-radiative recombination rate of carriers in semiconductor photovoltaic materials is of great significance to their application in the photovoltaic field. However, the current measurement of the non-radiative recombination rate of carriers in semiconductor materials usually requires the preparation of the material into a device or supplemented by complex theoretical analysis. Summary of the Invention

[0004] To overcome the limitations of existing technologies, the present invention provides a method for monitoring the non-radiative recombination rate of carriers in semiconductor photovoltaic materials based on transient absorption spectroscopy. Specifically, lifetime fitting is performed on the kinetic curve of the absorption signal of deep bound state carriers in the short-wavelength region of the absorption spectrum. Based on the inverse relationship between the carrier lifetime and the non-radiative recombination rate induced by internal defects in the material, effective monitoring of the non-radiative recombination rate of carriers in semiconductor materials is achieved. This monitoring method has the significant advantages of simple operation and ease of analysis. It is compatible with a variety of semiconductor manufacturing processes and can meet the monitoring requirements of different semiconductor photovoltaic materials, making it suitable for application and research in a variety of environments.

[0005] The above-mentioned object of the present invention is achieved through the following technical solutions:

[0006] A method for monitoring the non-radiative recombination rate of carriers in semiconductor photovoltaic materials uses transient absorption spectroscopy to test the semiconductor material, then performs lifetime fitting on the deep bound state carrier absorption signal in the short-wave region. Based on the lifetime, the speed of the non-radiative recombination rate caused by defects inside the semiconductor material is monitored to obtain bulk carrier recombination information of the semiconductor material.

[0007] Furthermore, lifetime fitting is performed on the absorption signal of deep bound state carriers in the short wavelength region, specifically, lifetime fitting is performed on the dynamic curve of deep energy level bound state carriers at short wavelength.

[0008] Furthermore, the non-radiative recombination rate of carriers is monitored based on the inverse relationship between the lifetime of deep bound state carriers and the non-radiative recombination rate.

[0009] Furthermore, semiconductor materials include but are not limited to antimony-based and copper-based compound semiconductors and organic-inorganic hybrid photovoltaic materials.

[0010] Furthermore, the semiconductor material is in the form of powder or thin film.

[0011] Furthermore, semiconductor material preparation processes include but are not limited to aqueous solution method, physical vapor deposition, chemical vapor deposition and atomic layer deposition.

[0012] Furthermore, before the transient absorption spectroscopy test, the semiconductor material can be subjected to an X-ray diffraction (XRD) test to determine its crystal structure and phase composition.

[0013] The present invention also seeks to protect the application of the above monitoring method in monitoring Sb2(S,Se)3 semiconductor films.

[0014] The beneficial effects of the present invention compared with the prior art are:

[0015] (1) Efficient and convenient: Based on transient absorption spectroscopy technology, the present invention provides an efficient and convenient method for monitoring the non-radiative recombination rate of carriers in semiconductor materials. This monitoring method has the technical advantages of short test cycle, simple operation, intuitive results and easy analysis.

[0016] (2) High compatibility with various existing semiconductor fabrication processes: This method is fully compatible with existing semiconductor fabrication processes (including but not limited to aqueous solution methods, physical vapor deposition, chemical vapor deposition, and atomic layer deposition) and is applicable to various semiconductor photovoltaic materials prepared through different process paths. Furthermore, this method is non-selective with respect to sample morphology and can monitor powdered or thin film samples.

[0017] (3) Can meet the monitoring needs of different semiconductor photovoltaic materials: The present invention can meet the monitoring needs of different types of semiconductor photovoltaic materials (including but not limited to antimony-based, copper-based compound semiconductors and organic-inorganic hybrid photovoltaic materials), and is suitable for application and research in various environments. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 XRD patterns of Sb2(S,Se)3 thin films with different Sb / S ratios in the examples;

[0019] Figure 2 The transient absorption spectra of Sb2(S,Se)3 thin films with different Sb / S ratios in the examples are shown. Figure (a) is the transient absorption spectrum of Sb2(S,Se)3 thin films with Sb / S=2 / 4.55; Figure (b) is the transient absorption spectrum of Sb2(S,Se)3 thin films with Sb / S=2 / 4.05; Figure (c) is the transient absorption spectrum of Sb2(S,Se)3 thin films with Sb / S=2 / 3.55; Figure (d) is the transient absorption spectrum of Sb2(S,Se)3 thin films with Sb / S=2 / 3.05; Figure (e) is the transient absorption spectrum of Sb2(S,Se)3 thin films with Sb / S=2 / 2.55.

[0020] Figure 3 The kinetic curves of Sb2(S,Se)3 thin films with different Sb / S ratios at 525nm are shown in the examples. Figure (a) shows the kinetic curve of Sb2(S,Se)3 thin films with Sb / S = 2 / 4.55 at 525nm; Figure (b) shows the kinetic curve of Sb2(S,Se)3 thin films with Sb / S = 2 / 4.05 at 525nm; Figure (c) shows the kinetic curve of Sb2(S,Se)3 thin films with Sb / S = 2 / 3.55 at 525nm; Figure (d) shows the kinetic curve of Sb2(S,Se)3 thin films with Sb / S = 2 / 3.05 at 525nm; and Figure (e) shows the kinetic curve of Sb2(S,Se)3 thin films with Sb / S = 2 / 2.55 at 525nm. DETAILED DESCRIPTION

[0021] The present invention provides a method for monitoring the non-radiative recombination rate of carriers in semiconductor photovoltaic materials using transient absorption spectroscopy. The present invention uses transient absorption spectroscopy to test semiconductor materials, and then performs lifetime fitting on the deep bound state carrier absorption signal in the short-wave region. Based on the lifetime, the speed of the non-radiative recombination rate caused by defects inside the material is monitored to obtain the carrier recombination information in the bulk phase of the material.

[0022] The method for monitoring the non-radiative recombination rate of carriers in semiconductor photovoltaic materials provided by the present invention comprises the following steps:

[0023] Step 1: Determine the semiconductor materials to be monitored;

[0024] Step 2: Perform X-ray diffraction (XRD) testing on the semiconductor material to be monitored in step 1 to determine its crystal structure and phase composition;

[0025] Step 3: Perform transient absorption spectroscopy testing on the semiconductor material to be monitored in step 1, and then perform lifetime fitting on the kinetic curve of deep-level bound state carriers at short wavelengths. Based on the inverse relationship between lifetime and recombination rate, monitor the non-radiative recombination rate caused by deep-level defects in the bulk phase of the material.

[0026] In order to make the purpose and technical solution of the present invention clearer and more specific, the present invention is further described in detail with reference to the following specific embodiments. It should be understood that the examples of the specific embodiments described herein are only for further explanation of the present invention, and are not intended to limit the present invention.

[0027] Example 1

[0028] Taking Sb2(S,Se)3 semiconductor thin film as the monitoring object

[0029] A method for monitoring the non-radiative recombination rate of Sb2(S,Se)3 semiconductor carriers comprises the following steps:

[0030] (1) Preparation of Sb2(S,Se)3 semiconductor thin film: Select appropriate antimony source, sulfur source and suitable solvent to prepare Sb-S precursor solutions with Sb / S ratios of 2 / 4.55 to 2 / 2.55 (2 / 4.55, 2 / 4.05, 2 / 3.55, 2 / 3.05, 2 / 2.55). Then, move the Sb-S precursor solution to a nitrogen-filled glove box and spin-coat the precursor film on a clean ITO substrate. After spin coating, immediately place the obtained film on a heating table for preheating and baking. After repeated spin coating and baking, an Sb2S3 precursor film with an appropriate thickness is obtained. Finally, the above-mentioned precursor film is placed in a graphite box containing Se particles and annealed at high temperature in a rapid heating tube furnace to obtain Sb2(S,Se)3 semiconductor films with different Sb / S ratios.

[0031] (2) XRD test of Sb2(S,Se)3 semiconductor films: Sb2(S,Se)3 films with different Sb / S ratios (2 / 4.55, 2 / 4.05, 2 / 3.55, 2 / 3.05, and 2 / 2.55) prepared in this embodiment were tested by XRD. Figure 1 It can be concluded that the prepared samples are all Sb2(S,Se)3 thin films with stibnite structure.

[0032] (3) Transient absorption spectrum test and deep energy level bound state carrier lifetime fitting of Sb2(S,Se)3 semiconductor films: Transient absorption spectrum test was performed on Sb2(S,Se)3 films with different Sb / S ratios (2 / 4.55, 2 / 4.05, 2 / 3.55, 2 / 3.05, 2 / 2.55) prepared in this embodiment, and then the kinetic curve lifetime of deep energy level bound state carriers at short wavelength was fitted.

[0033] (4) Analysis of non-radiative recombination rate of carriers in Sb2(S,Se)3 semiconductor films: Figure 2 It can be seen from the transient absorption spectrum test that the Sb2(S,Se)3 films with different Sb / S ratios (2 / 4.55, 2 / 4.05, 2 / 3.55, 2 / 3.05, 2 / 2.55) prepared in this embodiment all observed absorption peaks belonging to deep bound state carriers at 525nm; and Figure 3 It can be seen that as the Sb / S ratio gradually increases, the lifetime of deep bound state carriers at 525nm shows a trend of first increasing and then decreasing, reaching a maximum when Sb / S = 2 / 3.55. Based on the inverse relationship between the lifetime of deep bound state carriers and the non-radiative recombination rate, it can be found that when Sb / S = 2 / 3.55, the Sb2(S,Se)3 semiconductor film prepared in this example has the slowest non-radiative recombination rate and the lowest defect state density, making it suitable for use as a light-absorbing layer material for photovoltaic devices. Therefore, by testing the transient absorption spectrum and fitting the test results, the non-radiative recombination rate of semiconductor carriers can be monitored.

[0034] The above-described embodiments are only preferred embodiments of the present invention, and are not intended to be all feasible embodiments of the present invention. Any obvious modifications made by a person skilled in the art without departing from the principles and spirit of the present invention should be considered to be included within the scope of protection of the claims of the present invention.

Claims

1. A method for monitoring the non-radiative recombination rate of carriers in semiconductor photovoltaic materials, characterized in that: Semiconductor materials are tested using transient absorption spectroscopy, and then the lifetime of the deep bound state carrier absorption signal in the short-wave region is fitted. The non-radiative recombination rate caused by defects inside the semiconductor material is monitored based on the lifetime, and the bulk carrier recombination information of the semiconductor material is obtained.

2. The method for monitoring the non-radiative recombination rate of carriers in semiconductor photovoltaic materials according to claim 1, wherein: The lifetime fitting is performed on the absorption signal of deep bound state carriers in the short wavelength region, specifically: the lifetime fitting is performed on the dynamic curve of deep energy level bound state carriers at short wavelength.

3. The method for monitoring the non-radiative recombination rate of carriers in semiconductor photovoltaic materials according to claim 1, wherein: The non-radiative recombination rate of carriers is monitored based on the inverse relationship between the lifetime of deep bound state carriers and the non-radiative recombination rate.

4. The method for monitoring the non-radiative recombination rate of carriers in semiconductor photovoltaic materials according to claim 1, wherein: Semiconductor materials include but are not limited to antimony-based and copper-based compound semiconductors and organic-inorganic hybrid photovoltaic materials.

5. The method for monitoring the non-radiative recombination rate of carriers in semiconductor photovoltaic materials according to claim 1, wherein: Semiconductor materials are in the form of powder or thin film.

6. The method for monitoring the non-radiative recombination rate of carriers in semiconductor photovoltaic materials according to claim 1, wherein: Semiconductor material preparation processes include but are not limited to aqueous solution method, physical vapor deposition, chemical vapor deposition and atomic layer deposition.

7. The method for monitoring the non-radiative recombination rate of carriers in semiconductor photovoltaic materials according to claim 1, wherein: Before the transient absorption spectroscopy test, the semiconductor material is subjected to X-ray diffraction test to determine its crystal structure and phase composition.

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