Model selection method of photovoltaic device composite mechanism and related equipment

Abstract

The invention discloses a photovoltaic device composite mechanism analysis method and related equipment, and relates to the technical field of photovoltaic devices, and the method comprises the steps: obtaining a carrier lifetime model, a discrete defect energy level model and a continuous defect energy level model; respectively carrying out recombination rate calculation on the carrier lifetime model, the discrete defect energy level model and the continuous defect energy level model based on a finite element simulation method; obtaining a first current-voltage characteristic curve of a carrier lifetime model, a second current-voltage characteristic curve of a discrete defect energy level model and a third current-voltage characteristic curve of a continuous defect energy level model; obtaining an open-circuit voltage of a carrier lifetime model according to the first current-voltage characteristic curve, obtaining an open-circuit voltage of a discrete defect energy level model according to the second current-voltage characteristic curve, and obtaining an open-circuit voltage of a continuous defect energy level model according to the third current-voltage characteristic curve; and selecting the model corresponding to the maximum open-circuit voltage value as an optimal model for performing performance optimization on the photovoltaic device.

Description

Technical Field

[0001] This application relates to the technical field of photovoltaic devices, and particularly to a method for selecting a model of the recombination mechanism of a photovoltaic device and related equipment. Background Art

[0002] At present, with the growing global demand for clean energy, photovoltaic devices, as an important renewable energy technology, have received extensive attention. The performance of photovoltaic devices mainly depends on the behavior of internal carriers, and carrier recombination is one of the key factors affecting device performance. In photovoltaic devices, the recombination mechanism is mainly divided into non-radiative recombination and radiative recombination. Among them, radiative recombination can be utilized to generate light radiation to a certain extent, but non-radiative recombination has a significant negative impact on the open-circuit voltage and efficiency of the device. There are various common non-radiative recombination paths. For example, recombination caused by limited carrier lifetime, in this case, carriers recombine rapidly in a short time, reducing the number of carriers participating in the generation of photocurrent; recombination caused by continuously distributed defect energy levels, due to the existence of continuous defect energy levels in the semiconductor, carriers are prone to recombine at these energy levels; and recombination caused by discrete defect energy levels, discrete defect energy levels also become centers of carrier recombination.

[0003] However, currently, by selecting a model through the preliminary observation of some device performance parameters (such as open-circuit voltage, efficiency, etc.), this model has the problems of relatively limited analysis and low performance of photovoltaic devices. Summary of the Invention

[0004] A series of simplified concepts are introduced in the Summary of the Invention section, which will be further described in detail in the Detailed Description section. The Summary of the Invention section of this application does not mean to attempt to define the key features and essential technical features of the claimed technical solution, nor does it mean to attempt to determine the protection scope of the claimed technical solution.

[0005] In a first aspect, an embodiment of this application provides a method for selecting a model of the recombination mechanism of a photovoltaic device, and the method includes:

[0006] Obtain a carrier lifetime model, a discrete defect energy level model, and a continuous defect energy level model. The carrier lifetime model is used to characterize the corresponding relationship between the recombination lifetime of carriers and time in a photovoltaic device. The discrete defect energy level model is used to characterize the corresponding relationship between the energy level positions of discrete defects and carriers in a photovoltaic device. The continuous defect energy level model is used to characterize the corresponding relationship between the positions of continuously distributed defect energy levels and carriers in a photovoltaic device;

[0007] The recombination rates of the carrier lifetime model, the discrete defect energy level model, and the continuous defect energy level model are calculated respectively based on the finite element simulation method, and the first current-voltage characteristic curve of the carrier lifetime model, the second current-voltage characteristic curve of the discrete defect energy level model, and the third current-voltage characteristic curve of the continuous defect energy level model are obtained. The first current-voltage characteristic curve is used to characterize the corresponding relationship between current and voltage in the carrier lifetime model, the second current-voltage characteristic curve is used to characterize the corresponding relationship between current and voltage in the discrete defect energy level model, and the third current-voltage characteristic curve is used to characterize the corresponding relationship between current and voltage in the continuous defect energy level model;

[0008] The open-circuit voltage of the carrier lifetime model is obtained according to the first current-voltage characteristic curve, the open-circuit voltage of the discrete defect energy level model is obtained according to the second current-voltage characteristic curve, and the open-circuit voltage of the continuous defect energy level model is obtained according to the third current-voltage characteristic curve;

[0009] The model corresponding to the maximum open-circuit voltage value is selected as the optimal model for optimizing the performance of the photovoltaic device.

[0010] In an embodiment of the present invention, the step of calculating the recombination rates of the carrier lifetime model, the discrete defect energy level model, and the continuous defect energy level model respectively based on the finite element simulation method, and obtaining the first current-voltage characteristic curve of the carrier lifetime model, the second current-voltage characteristic curve of the discrete defect energy level model, and the third current-voltage characteristic curve of the continuous defect energy level model includes:

[0011] The recombination lifetimes of carriers in the carrier lifetime model are substituted into the Shockley recombination rate formula for solution to obtain the first electron recombination rate and the first hole recombination rate of the carrier lifetime model;

[0012] Based on the first electron recombination rate and the first hole recombination rate, the continuity equation of the semiconductor is calculated to obtain the first functional relationship between current and voltage in the carrier lifetime model;

[0013] Based on time and the first functional relationship between current and voltage, a first current-voltage characteristic curve is obtained.

[0014] In an embodiment of the present invention, the Shockley recombination rate formula is:

[0015]

[0016] where np is the recombination behavior of electrons in the conduction band and holes in the valence band, is the distribution of electrons and holes under thermal equilibrium, τn is the recombination lifetime of electrons, τ p is the recombination lifetime of holes, n + n1 is the sum of the conduction band electron density and the defect state electron concentration, p + p1 is the sum of the valence band hole density and the defect state hole concentration, R n is the electron recombination rate, R p is the hole recombination rate.

[0017] In one embodiment of the present invention, the step of calculating the recombination rate for the carrier lifetime model, the discrete defect energy level model, and the continuous defect energy level model respectively based on the finite element simulation method to obtain the first current-voltage characteristic curve of the carrier lifetime model, the second current-voltage characteristic curve of the discrete defect energy level model, and the third current-voltage characteristic curve of the continuous defect energy level model further includes:

[0018] Substitute the energy level positions of the discrete defects in the discrete defect energy level model into the Fermi–Dirac distribution function for solution to obtain the carrier occupancy probability of the discrete defect energy level model;

[0019] Based on the carrier occupancy probability, determine the second electron recombination rate, the second hole recombination rate, and the defect charge of the discrete defect energy level model;

[0020] Based on the second electron recombination rate, the second hole recombination rate, and the defect charge, calculate the continuity equation to obtain the second functional relationship between current and voltage in the discrete defect energy level model;

[0021] Based on time and the second functional relationship between current and voltage, obtain the second current-voltage characteristic curve.

[0022] In one embodiment of the present invention, the Fermi–Dirac distribution function is:

[0023]

[0024] where E t is the defect energy level position, E f is the Fermi level, k B T is the thermal energy of the photovoltaic device, k B is the Boltzmann constant, T is the temperature of the photovoltaic device, g D is the defect state degeneracy factor, f t is the carrier occupancy probability.

[0025] In one embodiment of the present invention, the step of calculating the recombination rates of the carrier lifetime model, the discrete defect energy level model, and the continuous defect energy level model respectively based on the finite element simulation method to obtain the first current-voltage characteristic curve of the carrier lifetime model, the second current-voltage characteristic curve of the discrete defect energy level model, and the third current-voltage characteristic curve of the continuous defect energy level model further includes:

[0026] Substitute the continuously distributed defect energy level positions in the continuous defect energy level model into the defect state density function and the Fermi–Dirac distribution function respectively for solution to obtain the defect state density distribution and the occupancy probability of the continuous defect energy level model;

[0027] Based on the defect state density distribution and the occupancy probability, determine the total defect charge, the third electron recombination rate, and the third hole recombination rate of the continuous defect energy level model;

[0028] Calculate the continuity equation based on the total defect charge, the third electron recombination rate, and the third hole recombination rate to obtain the third functional relationship between current and voltage in the continuous defect energy level model;

[0029] Based on time and the third functional relationship between current and voltage, obtain the third current-voltage characteristic curve.

[0030] In one embodiment of the present invention, the defect state density function is:

[0031]

[0032] where N t is the total defect state density, E t,0 is the central energy level of the defect state density distribution, σ is the standard deviation of the energy level distribution, E t is the defect energy level position, g t (E t ) is the defect state density distribution;

[0033] The occupancy probability is calculated by the following formula:

[0034]

[0035] where E t is the defect energy level position, E f is the Fermi level, k B T is the thermal energy of the photovoltaic device, k B is the Boltzmann constant, T is the temperature of the photovoltaic device, g D is the defect state degeneracy factor, f t (E t ) is the occupancy probability.

[0036] Second aspect, the present application proposes a model selection system for a photovoltaic device recombination mechanism, the system comprising: a data acquisition module, a solution module and an analysis module;

[0037] The data acquisition module is configured to: acquire a carrier lifetime model, a discrete defect energy level model and a continuous defect energy level model, the carrier lifetime model being used to characterize the correspondence between the recombination lifetime of carriers in a photovoltaic device and time, the discrete defect energy level model being used to characterize the correspondence between the energy level positions of discrete defects in a photovoltaic device and carriers, and the continuous defect energy level model being used to characterize the correspondence between the energy level positions of continuously distributed defects in a photovoltaic device and carriers;

[0038] The solution module is configured to: respectively calculate the recombination rates of the carrier lifetime model, the discrete defect energy level model and the continuous defect energy level model based on the finite element simulation method, to obtain a first current-voltage characteristic curve of the carrier lifetime model, a second current-voltage characteristic curve of the discrete defect energy level model and a third current-voltage characteristic curve of the continuous defect energy level model, the first current-voltage characteristic curve being used to characterize the correspondence between current and voltage in the carrier lifetime model, the second current-voltage characteristic curve being used to characterize the correspondence between current and voltage in the discrete defect energy level model, and the third current-voltage characteristic curve being used to characterize the correspondence between current and voltage in the continuous defect energy level model;

[0039] The analysis module is configured to: obtain the open-circuit voltage of the carrier lifetime model according to the first current-voltage characteristic curve, the open-circuit voltage of the discrete defect energy level model according to the second current-voltage characteristic curve, and the open-circuit voltage of the continuous defect energy level model according to the third current-voltage characteristic curve; select the model corresponding to the maximum open-circuit voltage value as the optimal model for optimizing the performance of the photovoltaic device.

[0040] Third aspect, an electronic device, comprising: a memory, a processor, and a computer program stored in the memory and executable on the processor, the processor being configured to implement the steps of a model selection method for a photovoltaic device recombination mechanism according to any one of the first aspects when executing the computer program stored in the memory.

[0041] Fourth aspect, the present application also proposes a computer-readable storage medium, on which a computer program is stored, the computer program being configured to implement the steps of a model selection method for a photovoltaic device recombination mechanism according to any one of the first aspects when executed by a processor.

[0042] In summary, for a method of selecting a model for the recombination mechanism of a photovoltaic device according to an embodiment of the present application, the recombination rates of the carrier lifetime model, the discrete defect energy level model, and the continuous defect energy level model are calculated respectively through a finite element simulation method, and a first current-voltage characteristic curve of the carrier lifetime model, a second current-voltage characteristic curve of the discrete defect energy level model, and a third current-voltage characteristic curve of the continuous defect energy level model are obtained, and the open circuit voltages of the above three current-voltage characteristic curves are compared to select an optimal model for optimizing the performance of the photovoltaic device, achieving the purpose of effectively reducing non-radiative recombination losses and improving the performance of the photovoltaic device.

[0043] For the method of selecting a model for the recombination mechanism of a photovoltaic device proposed in the present application, other advantages, objectives, and features of the present application will be partially reflected by the following description, and will also be understood by those skilled in the art through the research and practice of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] By reading the following detailed description of the preferred embodiments, various other advantages and benefits will become clear to those of ordinary skill in the art. The drawings are only for the purpose of showing the preferred embodiments and are not considered to limit this specification. Moreover, throughout the drawings, the same reference numerals are used to represent the same components. In the drawings:

[0045] Figure 1 It is a schematic flow chart of a method for selecting a model for the recombination mechanism of a photovoltaic device provided by an embodiment of the present application;

[0046] Figure 2 It is a current-voltage characteristic curve under three different recombination mechanisms in a method for selecting a model for the recombination mechanism of a photovoltaic device provided by an embodiment of the present application;

[0047] Figure 3 It is a schematic structural diagram of a system for selecting a model for the recombination mechanism of a photovoltaic device provided by an embodiment of the present application;

[0048] Figure 4 It is a schematic structural diagram of an electronic device for selecting a model for the recombination mechanism of a photovoltaic device provided by an embodiment of the present application. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0049] In order to better understand the technical solutions provided by the embodiments of this specification, the technical solutions of the embodiments of this specification will be described in detail below through the drawings and specific embodiments. It should be understood that the specific features in the embodiments of this specification and the embodiments are detailed descriptions of the technical solutions of the embodiments of this specification, rather than limitations on the technical solutions of this specification. Without conflict, the technical features in the embodiments of this specification and the embodiments can be combined with each other.

[0050] In this text, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "comprising", "including" or any other variant thereof are intended to cover non-exclusive inclusion, such that a process, method, article or device comprising a series of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article or device. Without further limitation, an element defined by the statement "comprising an..." does not exclude the presence of additional identical elements in the process, method, article or device comprising the element. The term "more than two" includes two or more than two cases.

[0051] Please refer to Figure 1 , which is a schematic flowchart of a method for selecting a model of a photovoltaic device composite mechanism provided by an embodiment of the present application, and specifically may include:

[0052] S110. Obtain a carrier lifetime model, a discrete defect energy level model, and a continuous defect energy level model. The carrier lifetime model is used to characterize the correspondence between the recombination lifetime of carriers in a photovoltaic device and time. The discrete defect energy level model is used to characterize the correspondence between the energy level positions of discrete defects in a photovoltaic device and carriers. The continuous defect energy level model is used to characterize the correspondence between the continuously distributed defect energy level positions in a photovoltaic device and carriers.

[0053] Exemplarily, the carrier lifetime model is used to present the correspondence between the recombination lifetime of carriers in a photovoltaic device and time. Carrier lifetime is one of the key factors affecting the performance of photovoltaic devices. During the operation of a photovoltaic device, carriers are continuously generated and recombined. The carrier lifetime model helps to understand the time that carriers experience from generation to recombination, and how this time changes with various factors (such as light intensity, temperature, material properties, etc.). By studying this correspondence, the behavior of carriers can be better understood, and then the design of photovoltaic devices can be optimized to improve their photoelectric conversion efficiency.

[0054] The discrete defect energy level model is used to describe the energy level positions of discrete defects in a photovoltaic device and the correspondence between these positions and carriers. In the semiconductor material of a photovoltaic device, discrete defects are some isolated and discontinuous defect positions. These discrete defects have specific energy levels, and they will have an important impact on the behavior of carriers. The discrete defect energy level model can understand the energy level distribution of these discrete defects in the device, and the interaction mode between carriers and these discrete defect energy levels. Furthermore, by adjusting the energy levels of discrete defects, the impact on carrier recombination can be minimized, thereby improving the performance of photovoltaic devices.

[0055] The continuous defect energy level model is used to describe the correspondence between the positions of continuously distributed defect energy levels and carriers in a photovoltaic device. Different from discrete defects, continuous defect energy levels form a continuous energy range in a semiconductor material. Such continuously distributed defect energy levels also affect the movement and recombination of carriers. The continuous defect energy level model can master the distribution range of these continuous defect energy levels and the interaction laws between them and carriers. Based on this model, the interaction between carriers and continuous defect energy levels can be adjusted to improve the performance of a photovoltaic device.

[0056] S120. Respectively calculate the recombination rates of the carrier lifetime model, the discrete defect energy level model, and the continuous defect energy level model based on the finite element simulation method, to obtain a first current-voltage characteristic curve of the carrier lifetime model, a second current-voltage characteristic curve of the discrete defect energy level model, and a third current-voltage characteristic curve of the continuous defect energy level model. The first current-voltage characteristic curve is used to characterize the correspondence between current and voltage in the carrier lifetime model, the second current-voltage characteristic curve is used to characterize the correspondence between current and voltage in the discrete defect energy level model, and the third current-voltage characteristic curve is used to characterize the correspondence between current and voltage in the continuous defect energy level model.

[0057] Exemplarily, finite element simulation is a numerical calculation technique. In the research of photovoltaic devices, it can decompose complex physical problems (such as the behavior of carriers under different models) into many simple small regions (finite elements), and finally obtain the physical characteristics of the entire system by performing mathematical modeling and calculations on each small region. The recombination rate refers to the speed of carrier recombination. In a photovoltaic device, the carrier recombination rate directly affects the performance of the device.

[0058] After calculating the recombination rate of the carrier lifetime model, perform correlation analysis on the relationship between the obtained recombination rate and other information and current and voltage to obtain the first current-voltage characteristic curve of the carrier lifetime model. This curve can intuitively show how the current changes with the voltage in the carrier lifetime model. Similarly, calculate the recombination rate for the discrete defect energy level model. Consider factors such as the energy level position of discrete defects in the photovoltaic device and their interaction with carriers to obtain the second current-voltage characteristic curve of the discrete defect energy level model, which reflects the correspondence between current and voltage in the discrete defect energy level model. Calculate the recombination rate for the continuous defect energy level model and obtain the current values at different voltages, and then obtain the third current-voltage characteristic curve of the continuous defect energy level model. This curve is used to show the variation law of current with voltage in the continuous defect energy level model.

[0059] S130. Obtain the open-circuit voltage of the carrier lifetime model from the first current-voltage characteristic curve, the open-circuit voltage of the discrete defect energy level model from the second current-voltage characteristic curve, and the open-circuit voltage of the continuous defect energy level model from the third current-voltage characteristic curve.

[0060] Exemplarily, the open-circuit voltage refers to the voltage across the two ends of a photovoltaic device when it is not connected to an external load (i.e., in the open-circuit state). In this case, no current flows out of the device, that is, the current value is zero. The first current-voltage characteristic curve depicts the correspondence between current and voltage in the carrier lifetime model. On this curve, we look for the point where the current value is zero. Since the current is zero in the open-circuit state, the voltage value corresponding to this zero current is the open-circuit voltage of the carrier lifetime model. Usually, on the plotted first current-voltage characteristic curve, the position where the current equals zero can be found by direct observation or mathematical methods (such as interpolation method if the curve data is discrete), and then its corresponding voltage value can be determined. This open-circuit voltage reflects the magnitude of the voltage that the photovoltaic device can generate without load under the carrier recombination mechanism described by the carrier lifetime model.

[0061] The second current-voltage characteristic curve characterizes the relationship between current and voltage in the discrete defect energy level model. Similarly, we look for the point where the current value is zero on this curve. The voltage corresponding to this point is the open-circuit voltage of the discrete defect energy level model. Discrete defects have specific energy levels in the semiconductor material of the photovoltaic device, and these energy levels interact with carriers, affecting the carrier recombination process. The open-circuit voltage obtained from this curve reflects the influence of discrete defect energy levels on the open-circuit voltage of the device.

[0062] For the third current-voltage characteristic curve, it shows the correspondence between current and voltage under the continuous defect energy level model. Still taking the zero current value as the search target, the voltage corresponding to this point is the open-circuit voltage of the continuous defect energy level model. The continuous defect energy levels form a continuous energy range in the semiconductor material, having a comprehensive impact on the behavior of carriers. The open-circuit voltage obtained from this curve reflects the effect of the continuous defect energy level distribution on the open-circuit voltage of the device.

[0063] S140. Select the model corresponding to the maximum open-circuit voltage value as the optimal model for optimizing the performance of the photovoltaic device.

[0064] Exemplarily, the open-circuit voltage is a key indicator for measuring the performance of a photovoltaic device. In an ideal situation, the higher the open-circuit voltage, the greater the potential difference that the photovoltaic device can generate under no-load conditions. When a load is connected, there is a greater potential to output electrical energy. A higher open-circuit voltage usually reflects better charge separation within the device and relatively less carrier recombination loss, which is crucial for improving the photoelectric conversion efficiency of the photovoltaic device. Therefore, the open-circuit voltage largely represents the performance quality of the photovoltaic device. Consequently, the model corresponding to the maximum open-circuit voltage value is selected as the optimal model for optimizing the performance of the photovoltaic device.

[0065] In summary, the method for selecting a model of the recombination mechanism of a photovoltaic device proposed in the embodiments of the present application calculates the recombination rates of the carrier lifetime model, the discrete defect energy level model, and the continuous defect energy level model respectively through a finite element simulation method, obtains the first current-voltage characteristic curve of the carrier lifetime model, the second current-voltage characteristic curve of the discrete defect energy level model, and the third current-voltage characteristic curve of the continuous defect energy level model, and compares the open-circuit voltages of the above three current-voltage characteristic curves to select the optimal model for optimizing the performance of the photovoltaic device, achieving the purpose of effectively reducing non-radiative recombination loss and improving the performance of the photovoltaic device.

[0066] In some examples, the step of calculating the recombination rates of the carrier lifetime model, the discrete defect energy level model, and the continuous defect energy level model respectively through a finite element simulation method, and obtaining the first current-voltage characteristic curve of the carrier lifetime model, the second current-voltage characteristic curve of the discrete defect energy level model, and the third current-voltage characteristic curve of the continuous defect energy level model includes:

[0067] Substitute the recombination lifetime of carriers in the carrier lifetime model into the Shockley recombination rate formula for solution to obtain the first electron recombination rate and the first hole recombination rate of the carrier lifetime model;

[0068] Calculate the continuity equation of the semiconductor based on the first electron recombination rate and the first hole recombination rate to obtain the first functional relationship between current and voltage in the carrier lifetime model;

[0069] Based on time and the first functional relationship between current and voltage, obtain the first current-voltage characteristic curve.

[0070] Exemplarily, the Shockley recombination rate formula is an important tool for describing the carrier recombination rate in semiconductors. It comprehensively considers various characteristics of semiconductor materials and factors such as carrier concentration to calculate the recombination rates of electrons and holes. Substituting the carrier recombination lifetimes determined in the carrier lifetime model into this formula for solution, the first electron recombination rate and the first hole recombination rate under this model can be obtained. These two recombination rates reflect the speed at which electrons and holes combine and disappear under the conditions set by the carrier lifetime model.

[0071] The continuity equation of semiconductors describes the relationship between carrier concentration and time and space. Based on the first electron recombination rate and the first hole recombination rate obtained previously, substituting them into the continuity equation of semiconductors for calculation, the first functional relationship between current and voltage in the carrier lifetime model can ultimately be obtained. This functional relationship describes how the current changes with the voltage under this model.

[0072] During the operation of an actual photovoltaic device, time is an important factor. Although the first functional relationship between current and voltage obtained previously describes the basic relationship between the two, in order to more comprehensively understand the performance of the device at different times, the time factor needs to be introduced. Based on time and the first functional relationship between current and voltage that has been obtained, by taking values and calculating the function at different time points, a series of corresponding values of current and voltage can be obtained. Plotting these corresponding values in a plane rectangular coordinate system (usually with voltage as the abscissa and current as the ordinate), the first current-voltage characteristic curve is obtained. This curve intuitively shows how the current of the photovoltaic device changes with the voltage under the carrier lifetime model and the law of this change at different time points.

[0073] In some examples, the Shockley recombination rate formula is:

[0074]

[0075] where np is the recombination behavior of electrons in the conduction band and holes in the valence band, is the distribution of electrons and holes under thermal equilibrium, τ n is the recombination lifetime of electrons, τ p is the recombination lifetime of holes, n + n1 is the sum of the conduction band electron density and the defect state electron concentration, p + p1 is the sum of the valence band hole density and the defect state hole concentration, R n is the electron recombination rate, R p is the hole recombination rate.

[0076] Exemplarily, the Hockley recombination rate formula comprehensively considers the thermal equilibrium carrier distribution, the recombination lifetimes of electrons and holes, and the carrier concentrations in the current conduction band, valence band, and defect states, and accurately calculates the first electron recombination rate and the first hole recombination rate through these parameters, where R n = R p describes the equilibrium condition of defect-assisted recombination, where the recombination rates of electrons and holes are equal. Since R n is the electron recombination rate, which describes the capture and release rates of electrons in the defect states. R p is the hole recombination rate, which describes the capture and release rates of holes in the defect states. Under thermal equilibrium, the capture rates of electrons and holes in the defect states are equal to the release rates, so R n = R p .

[0077] In some examples, the step of calculating the recombination rates for the carrier lifetime model, the discrete defect energy level model, and the continuous defect energy level model respectively based on the finite element simulation method, and obtaining the first current-voltage characteristic curve of the carrier lifetime model, the second current-voltage characteristic curve of the discrete defect energy level model, and the third current-voltage characteristic curve of the continuous defect energy level model further includes:

[0078] Substitute the energy level positions of the discrete defects in the discrete defect energy level model into the Fermi–Dirac distribution function for solution to obtain the carrier occupancy probability of the discrete defect energy level model;

[0079] Based on the carrier occupancy probability, determine the second electron recombination rate, the second hole recombination rate, and the defect charge of the discrete defect energy level model;

[0080] Based on the second electron recombination rate, the second hole recombination rate, and the defect charge, calculate the continuity equation to obtain the second functional relationship between current and voltage in the discrete defect energy level model;

[0081] Based on time and the second functional relationship between current and voltage, obtain the second current-voltage characteristic curve.

[0082] Exemplarily, substituting the specific energy level positions of discrete defects in the discrete defect energy level model into the Fermi–Dirac distribution function can calculate the probabilities that these discrete defect energy levels are occupied by carriers (electrons or holes) at a given temperature and Fermi level. The carrier occupation probability reflects the filling situation of carriers on the defect energy levels, which directly affects the recombination rate of electrons and holes through the defect energy levels. Based on the obtained carrier occupation probabilities, the second electron recombination rate and the second hole recombination rate under the discrete defect energy level model can be determined. These two recombination rates represent the speed of electron and hole recombination when considering discrete defect energy levels.

[0083] After discrete defect energy levels are occupied by carriers, they will carry a certain amount of charge, and the amount of charge is related to the type of carriers (electrons are negatively charged, holes are positively charged) and the occupation probability. By analyzing the occupation situation of carriers on the defect energy levels, the defect charges in the discrete defect energy level model can be determined. The distribution of defect charges will affect the internal electric field distribution of the semiconductor, and thus affect the transport of carriers.

[0084] Substitute the previously obtained information such as the second electron recombination rate, the second hole recombination rate, and defect charges into the continuity equation for calculation. During the calculation process, various characteristics of the semiconductor material (such as dielectric constant, mobility, etc.) and boundary conditions need to be considered. Finally, the second functional relationship between current and voltage in the discrete defect energy level model can be obtained. This functional relationship describes how the current changes with the voltage under the conditions set by the discrete defect energy level model.

[0085] Based on time and the second functional relationship between current and voltage obtained, the function is evaluated and calculated at different time points to obtain a series of corresponding values of current and voltage. Then these corresponding values are plotted in a rectangular coordinate system (usually with voltage as the abscissa and current as the ordinate), and the second current-voltage characteristic curve is obtained. This curve intuitively shows the characteristics of the current change with voltage of the semiconductor device under the discrete defect energy level model and the change of this characteristic at different times.

[0086] In some examples, the Fermi–Dirac distribution function is:

[0087]

[0088] where E t is the defect energy level position, E f is the Fermi level, k B T is the thermal energy of the photovoltaic device, k B is the Boltzmann constant, T is the temperature of the photovoltaic device, g D is the defect state degeneracy factor, f tis the carrier occupancy probability.

[0089] Exemplarily, the formula for defect-assisted recombination is as follows:

[0090] R n = R e (3);

[0091] This is the equilibrium condition for the recombination process of electrons. Among them, R n is the electron capture rate, that is, the electron recombination rate (i.e., the speed of transition from the conduction band to the defect state), and R e is the rate of electrons released from the defect state to the conduction band. Under thermal equilibrium conditions, the capture rate and the release rate are equal:

[0092] R p = R h (4);

[0093] This is the equilibrium condition for the recombination process of holes. Among them, R p is the hole capture rate, that is, the hole recombination rate (i.e., the rate of transition from the valence band to the defect state), and R h is the rate of holes released from the defect state to the valence band. Similar to electrons, the capture rate and the release rate are equal at thermal equilibrium, which means that holes also reach dynamic equilibrium on the defect state.

[0094] ρ + = Q t (5);

[0095] This is the condition for the charge distribution of the defect state. Among them, ρ + is the positive charge density of the defect center, representing the part of the defect state that is positively charged due to the loss of electrons. Q t is the total defect state density, including all possible defect states (regardless of whether they are occupied by electrons or holes).

[0096] For a single energy level defect state, this formula means that all defect states are not occupied by electrons, so they are completely positively charged. In actual simulations, this distribution may need to be combined with the Fermi-Dirac distribution function to describe the occupancy rate of the defect state, and the specific expression is:

[0097] ρ + = Q t (1 - f t )(6);

[0098] Among them, f t is the occupancy probability of the defect state (Fermi-Dirac distribution function). If it is a multi-energy level distribution, this formula needs to be further generalized.

[0099] Discrete defect energy levels indicate that the energy level distribution of defects in a material is discrete and localized. This is usually associated with defects at single energy levels or fixed energy levels. The carrier occupancy probability (Fermi-Dirac distribution function) is shown in Equation (2), where g D is the degeneracy factor of the defect state (i.e., the number of different states that can be occupied at this energy level). This formula is derived from the Fermi-Dirac distribution and describes the probability of electron filling in the iron defect energy level under thermal equilibrium conditions, depending on the relationship between the energy level position and the Fermi level.

[0100] Second electron recombination rate:

[0101]

[0102] where R e is the recombination rate of electrons through the defect state. C n is the product of the electron capture cross-section and the velocity (recombination rate constant). N t is the density of defect states. n is the electron concentration. n f is the electron concentration under equilibrium conditions. n1 corresponds to the thermal equilibrium electron concentration at energy level E t f t is the probability that the defect state is occupied. This is because the difference between the electron concentration and the defect state occupancy probability drives electron recombination.

[0103] Second hole recombination rate:

[0104] R h = C p N t (pf t + g D (p1f t - p1))(8);

[0105] where R h is the second hole recombination rate, the recombination rate of holes through the defect state. C p is the product of the hole capture cross-section and the velocity (recombination rate constant). p represents the hole concentration. p1 corresponds to the thermal equilibrium hole concentration at energy level E t The hole concentration and the occupancy of the defect state together determine the hole recombination rate.

[0106] Defect charge:

[0107]

[0108] where Q t is the charge density contributed by the defect state. q is the unit charge amount. f t is the occupancy probability of the defect state. N tis the density of defect states. E0 is a certain reference energy level (such as the band edge). In different energy level regions, the contributions of defect charges are different: when E t ≥ E0, the charge is dominated by occupied electrons (negative charges). When E t < E0, the charge is dominated by unoccupied states (hole contributions).

[0109] In some examples, the step of calculating the recombination rates of the carrier lifetime model, the discrete defect energy level model, and the continuous defect energy level model respectively by the finite element simulation method to obtain the first current-voltage characteristic curve of the carrier lifetime model, the second current-voltage characteristic curve of the discrete defect energy level model, and the third current-voltage characteristic curve of the continuous defect energy level model further includes:

[0110] Substitute the continuously distributed defect energy level positions in the continuous defect energy level model into the defect state density function and the Fermi–Dirac distribution function respectively for solution to obtain the defect state density distribution and the occupation probability of the continuous defect energy level model;

[0111] Based on the defect state density distribution and the occupation probability, determine the total defect charge, the third electron recombination rate, and the third hole recombination rate of the continuous defect energy level model;

[0112] Calculate the continuity equation based on the total defect charge, the third electron recombination rate, and the third hole recombination rate to obtain the third functional relationship between current and voltage in the continuous defect energy level model;

[0113] Based on time and the third functional relationship between current and voltage, obtain the third current-voltage characteristic curve.

[0114] Exemplarily, the defect state density function is used to describe the number of defect states per unit energy interval and per unit volume, which reflects the distribution density of defect energy levels in the energy space. Substituting the continuously distributed defect energy level positions into the defect state density function, the defect state density at each energy position can be obtained, and then the defect state density distribution in the entire energy range can be depicted. Substituting the continuous defect energy level positions into the Fermi–Dirac distribution function for solution can obtain the probability of each defect energy level being occupied by carriers, that is, the distribution of occupation probabilities. A comprehensive understanding of the distribution of continuous defect energy levels in the energy space and the possibility of these energy levels being occupied by carriers is achieved.

[0115] Each defect energy level will carry a corresponding charge after being occupied by a carrier. Combining the defect state density distribution (i.e., the number of defects at different energy positions) and the occupation probability (the probability of each energy level being occupied) obtained previously, the charge carried by the defect at each energy position can be calculated, and then the total defect charge in the semiconductor material can be obtained by integrating the entire energy range. The total defect charge reflects the overall impact of defects on the charge distribution inside the semiconductor, which will change the internal electric field distribution and thus affect the movement of carriers.

[0116] The defect state density distribution and occupation probability determine the degree and mode of interaction between carriers (electrons and holes) and defects. Based on this information, the recombination rates of electrons and holes under the continuous defect energy level model can be calculated, namely the third electron recombination rate and the third hole recombination rate. These two rates describe how fast electrons and holes recombine in the presence of continuous defect energy levels.

[0117] Substitute the total defect charge, the third electron recombination rate, and the third hole recombination rate obtained above into the continuity equation. In the calculation process, it is necessary to consider various properties of semiconductor materials (such as mobility, dielectric constant, etc.) and boundary conditions (such as voltage and current conditions at both ends of the device, etc.). By solving and deriving the continuity equation, the third functional relationship between current and voltage in the continuous defect energy level model can be finally obtained. This third functional relationship accurately describes how the current changes with the change of voltage in the continuous defect energy level model.

[0118] According to the third functional relationship between time and current and voltage obtained above, the function is evaluated and calculated at different time points to obtain a series of corresponding values ​​of current and voltage at different times. These corresponding values ​​are plotted in a plane rectangular coordinate system (usually with voltage as the horizontal coordinate and current as the vertical coordinate), and the third current-voltage characteristic curve can be obtained. This curve intuitively shows the characteristics of the current of semiconductor devices changing with voltage under the continuous defect energy level model, as well as the evolution of this characteristic at different times.

[0119] In some examples, the defect state density function is:

[0120]

[0121] Among them, N t is the total defect state density, E t,0 is the central energy level of the defect state density distribution, σ is the standard deviation of the energy level distribution, E t is the defect energy level position, g t (E t ) is the defect state density distribution;

[0122] The occupancy probability is calculated by the following formula:

[0123]

[0124] Among them, E t is the defect energy level position, E f is the Fermi energy level, k B T is the thermal energy of the photovoltaic device, k B is the Boltzmann constant, T is the temperature of the photovoltaic device, g D is the defect state degeneracy factor, f t (E t ) is the occupancy probability.

[0125] Exemplarily, the defect state density distribution is as shown in Equation (10), which is a Gaussian distribution and describes the distribution of defect energy levels between energy bands. Among them, σ is the standard deviation of the energy level distribution, representing the width of the distribution. The occupancy probability is as shown in Equation (11).

[0126] Total defect charge:

[0127]

[0128] Among them, Q t is the total defect state charge density when considering the continuous energy level distribution. is the negative charge contribution of the defect states above E0. is the contribution of holes (states not filled with electrons) below E0.

[0129] Third electron recombination rate:

[0130]

[0131] Among them, R e is the integral form of the third electron recombination rate for the continuous energy level distribution. That is, the electron recombination contribution of each energy level is considered and integrated over the entire defect state energy level distribution.

[0132] Third hole recombination rate:

[0133]

[0134] Among them, R h is the integral form of the third hole recombination rate for the continuous energy level distribution. That is, the hole recombination contribution of each energy level is accumulated to obtain the total recombination rate.

[0135] For discrete defect energy levels, assuming that the defect energy levels are discrete, calculations are performed separately for each energy level, which is applicable to the case of fewer local defects. For continuous defect energy levels, it is assumed that the defect energy levels follow a Gaussian distribution form, and the contributions of all energy levels need to be integrated, which is applicable to cases such as high defect density and tail states. These formulas help analyze the performance of semiconductor devices by precisely describing the influence of defect states on carrier recombination, charging, and charge distribution, especially in materials with energy level mismatches or a large number of defects.

[0136] As Figure 2 shown, this application presents the current-voltage characteristic curves under three different recombination mechanisms in a model selection method for the recombination mechanism of a photovoltaic device, corresponding to the carrier lifetime model, the continuous defect energy level model, and the discrete defect energy level model respectively. Analysis shows that these three recombination mechanisms have a significant impact on the open-circuit voltage of the photovoltaic device. Among them, the carrier lifetime model exhibits the lowest open-circuit voltage, while the continuous defect energy level and discrete defect energy level models exhibit the second-highest and highest open-circuit voltages respectively.

[0137] First, the carrier lifetime model exhibits the lowest open-circuit voltage. This is because in this mechanism, the recombination of carriers is simplified to a process with an average lifetime, without considering the specific defect state distribution. However, due to the relatively short average lifetime set, carriers are more likely to be consumed through non-radiative recombination processes, resulting in the device being unable to effectively maintain the concentration of photo-generated carriers, thus significantly reducing the open-circuit voltage of the device.

[0138] Secondly, the open-circuit voltage of the continuous defect energy level model is higher than that of the carrier lifetime model but still lower than that of the discrete defect energy level model. In this mechanism, it is assumed that the defect energy levels are continuously distributed in the forbidden band, resulting in carriers being able to recombine through multiple energy level paths. Although the continuously distributed defects increase the rate of non-radiative recombination, due to the relatively uniform distribution, some carriers can still escape the recombination process and participate in current transport. Therefore, the open-circuit voltage is relatively improved compared to the carrier lifetime model but cannot reach the optimal level.

[0139] Finally, the discrete defect energy level model exhibits the highest open-circuit voltage. This is because in this mechanism, the defect energy levels are assumed to be distributed at specific positions in the forbidden band, the recombination paths are limited, and the recombination rate is relatively low. Since the defect energy levels are discrete, some carriers can avoid these recombination centers and survive for a longer time, thus effectively reducing the non-radiative recombination loss and improving the open-circuit voltage of the device. This mechanism usually reflects the characteristics of high-quality materials because the density of discrete defects is relatively low.

[0140] In summary, for the carrier lifetime model: the recombination rate is relatively high, resulting in a short survival time of photo-generated carriers and the lowest open-circuit voltage; for the continuous defect energy level model: the defect energy levels are continuously distributed and there are more recombination paths, but some carriers can escape the recombination process, and the open-circuit voltage is the second highest; for the discrete defect energy level model: the defect energy levels are concentrated at specific positions, the recombination rate is the lowest, the survival time of photo-generated carriers is the longest, and the open-circuit voltage of the device is the highest. This indicates that optimizing the defect state distribution of the material, reducing the continuous defect density, and controlling the defect states to be finite discrete energy levels are effective means to improve the device performance, especially the open-circuit voltage. The present invention provides clear theoretical guidance for the optimization of photovoltaic device materials. By regulating the defect state distribution, the non-radiative recombination loss can be effectively reduced and the device performance can be improved.

[0141] As Figure 3 shown, the present application proposes a model selection system for the recombination mechanism of a photovoltaic device. The system includes: a data acquisition module 21, a solution module 22, and an analysis module 23;

[0142] The data acquisition module 21 is configured to: acquire a carrier lifetime model, a discrete defect energy level model, and a continuous defect energy level model. The carrier lifetime model is used to characterize the corresponding relationship between the recombination lifetime of carriers and time in a photovoltaic device. The discrete defect energy level model is used to characterize the corresponding relationship between the energy level positions of discrete defects and carriers in a photovoltaic device. The continuous defect energy level model is used to characterize the corresponding relationship between the continuously distributed defect energy level positions and carriers in a photovoltaic device;

[0143] The solution module 22 is configured to: respectively calculate the recombination rates of the carrier lifetime model, the discrete defect energy level model, and the continuous defect energy level model based on the finite element simulation method, and obtain a first current-voltage characteristic curve of the carrier lifetime model, a second current-voltage characteristic curve of the discrete defect energy level model, and a third current-voltage characteristic curve of the continuous defect energy level model. The first current-voltage characteristic curve is used to characterize the corresponding relationship between current and voltage in the carrier lifetime model. The second current-voltage characteristic curve is used to characterize the corresponding relationship between current and voltage in the discrete defect energy level model. The third current-voltage characteristic curve is used to characterize the corresponding relationship between current and voltage in the continuous defect energy level model;

[0144] The analysis module 23 is configured to: obtain the open-circuit voltage of the carrier lifetime model according to the first current-voltage characteristic curve, the open-circuit voltage of the discrete defect energy level model according to the second current-voltage characteristic curve, and the open-circuit voltage of the continuous defect energy level model according to the third current-voltage characteristic curve; select the model corresponding to the maximum open-circuit voltage value as the optimal model for optimizing the performance of the photovoltaic device.

[0145] The effects of applying the foregoing method in the above system can be referred to the descriptions in the foregoing method embodiments, and will not be elaborated here.

[0146] As Figure 4 shown, an embodiment of the present application further provides an electronic device 300, including a memory 310, a processor 320, and a computer program 311 stored on the memory 310 and executable on the processor. When the processor 320 executes the computer program 311, it implements the steps of any of the methods for model selection of the above photovoltaic device recombination mechanism.

[0147] Since the electronic device introduced in this embodiment is the device adopted by a model selection device for a photovoltaic device recombination mechanism in an embodiment of the present application, based on the method introduced in the embodiment of the present application, those skilled in the art can understand the specific implementation manners and various variations of the electronic device in this embodiment. Therefore, the implementation of how this electronic device implements the method in the embodiment of the present application will not be described in detail here. As long as the device adopted by those skilled in the art to implement the method in the embodiment of the present application belongs to the scope protected by the present application.

[0148] In the specific implementation process, when the computer program 311 is executed by the processor, it can implement Figure 1 any implementation manner in the corresponding embodiment.

[0149] It should be noted that in the above embodiments, the descriptions of each embodiment have their own focuses. For the parts not described in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0150] Those skilled in the art should understand that the embodiments of the present application can be provided as a method, a system, or a computer program product. Therefore, the present application can adopt the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware aspects. Moreover, the present application can adopt the form of a computer program product implemented on one or more computer-readable storage media (including but not limited to disk memories, CD-ROMs, optical memories, etc.) containing computer-readable program codes.

[0151] The present application is described with reference to the flowcharts and / or block diagrams of methods, devices (systems), and computer program products according to the embodiments of the present application. It should be understood that each flow and / or block in the flowcharts and / or block diagrams, and the combination of flows and / or blocks in the flowcharts and / or block diagrams can be implemented by computer program instructions. These computer program instructions can be provided to the processor of a general-purpose computer, a special-purpose computer, an embedded computer, or other programmable data processing devices to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing devices generate for implementing in the process Figure 1One or more processes and / or boxes Figure 1 Means for the functions specified in one or more boxes.

[0152] These computer program instructions may also be stored in a computer-readable memory that can direct a computer or other programmable data processing device to work in a specific manner, such that the instructions stored in the computer-readable memory produce a manufacture including an instruction means that implements the functions in the process Figure 1 One or more processes and / or boxes Figure 1 The functions specified in one or more boxes.

[0153] These computer program instructions may also be loaded onto a computer or other programmable data processing device, such that a series of operational steps are performed on the computer or other programmable device to produce a computer-implemented process, whereby the instructions executed on the computer or other programmable device provide for implementing the functions in the process Figure 1 One or more processes and / or boxes Figure 1 Steps for the functions specified in one or more boxes.

[0154] The embodiments of the present application also provide a computer program product, which includes computer software instructions. When the computer software instructions run on a processing device, the processing device is caused to execute the processes of the LDPC decoding method of the solid-state drive controller.

[0155] The computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, the processes or functions according to the embodiments of the present application are wholly or partially generated. The computer may be a general-purpose computer, a special-purpose computer, a computer network, or other programmable devices. The computer instructions may be stored in a computer-readable storage medium, or transmitted from one computer-readable storage medium to another. For example, the computer instructions may be transmitted from a website, computer, server, or data center to another website, computer, server, or data center by wire (such as coaxial cable, optical fiber, digital subscriber line (DSL)) or wirelessly (such as infrared, wireless, microwave, etc.). The computer-readable storage medium may be any available medium that can be stored by a computer or a data storage device such as a server or data center that integrates one or more available media. The available medium may be a magnetic medium (such as a floppy disk, hard disk, magnetic tape), an optical medium (such as a DVD), or a semiconductor medium (such as a solid-state disk (SSD)), etc.

[0156] Those skilled in the art can clearly understand that for the convenience and brevity of description, the specific working processes of the systems, devices, and units described above can refer to the corresponding processes in the foregoing method embodiments and will not be elaborated herein.

[0157] In several embodiments provided in the present application, it should be understood that the disclosed devices, apparatuses, and methods can be implemented in other ways. For example, the device embodiments described above are merely illustrative. For example, the division of units is only a logical function division, and there can be other division methods in actual implementation. For example, multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the displayed or discussed couplings or direct couplings or communication connections to each other can be through some interfaces, and the indirect couplings or communication connections of devices or units can be in electrical, mechanical, or other forms.

[0158] The units described as separate components may or may not be physically separated, and the components displayed as units may or may not be physical units, that is, they can be located in one place or distributed to multiple network units. Some or all of the units can be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0159] In addition, in each embodiment of the present application, the functional units can be integrated into one processing unit, or each unit can exist physically alone, or two or more units can be integrated into one unit. The above-mentioned integrated units can be implemented in the form of hardware or in the form of software functional units.

[0160] If the integrated unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present application, in essence, or the part that contributes to the prior art, or all or part of this technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions for causing a computer device (which can be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the methods in each embodiment of the present application. The foregoing storage medium includes: various media such as USB flash drives, mobile hard disks, read-only memories (ROMs), random access memories (RAMs), magnetic disks, or optical discs that can store program codes.

[0161] The above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit it; although the present application has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the various embodiments of the present application.

[0162] Although the preferred embodiments of this specification have been described, those skilled in the art can make additional changes and modifications once they know the basic creative concept. Therefore, the appended claims are intended to be construed to include the preferred embodiments as well as all changes and modifications falling within the scope of this specification.

[0163] Obviously, those skilled in the art can make various changes and modifications to this specification without departing from the spirit and scope of this specification. Thus, if these modifications and variations of this specification fall within the scope of the claims of this specification and their equivalent technologies, this specification is also intended to include these modifications and variations.

Claims

1. A method for selecting a model of a recombination mechanism of a photovoltaic device, characterized in that, The method includes: Obtaining a carrier lifetime model, a discrete defect energy level model, and a continuous defect energy level model. The carrier lifetime model is used to characterize the corresponding relationship between the recombination lifetime of carriers and time in a photovoltaic device. The discrete defect energy level model is used to characterize the corresponding relationship between the energy level positions of discrete defects and carriers in a photovoltaic device. The continuous defect energy level model is used to characterize the corresponding relationship between the continuously distributed defect energy level positions and carriers in a photovoltaic device; Based on the finite element simulation method, calculating the recombination rate for the carrier lifetime model, the discrete defect energy level model, and the continuous defect energy level model respectively, to obtain a first current-voltage characteristic curve of the carrier lifetime model, a second current-voltage characteristic curve of the discrete defect energy level model, and a third current-voltage characteristic curve of the continuous defect energy level model. The first current-voltage characteristic curve is used to characterize the corresponding relationship between current and voltage in the carrier lifetime model. The second current-voltage characteristic curve is used to characterize the corresponding relationship between current and voltage in the discrete defect energy level model. The third current-voltage characteristic curve is used to characterize the corresponding relationship between current and voltage in the continuous defect energy level model; Obtaining the open-circuit voltage of the carrier lifetime model according to the first current-voltage characteristic curve, the open-circuit voltage of the discrete defect energy level model according to the second current-voltage characteristic curve, and the open-circuit voltage of the continuous defect energy level model according to the third current-voltage characteristic curve; Selecting the model corresponding to the maximum open-circuit voltage value as the optimal model for optimizing the performance of the photovoltaic device.

2. The method for selecting a model of the photovoltaic device recombination mechanism according to claim 1, wherein The step of calculating the recombination rate for the carrier lifetime model, the discrete defect energy level model, and the continuous defect energy level model respectively based on the finite element simulation method to obtain a first current-voltage characteristic curve of the carrier lifetime model, a second current-voltage characteristic curve of the discrete defect energy level model, and a third current-voltage characteristic curve of the continuous defect energy level model includes: Substituting the recombination lifetime of carriers in the carrier lifetime model into the Shockley recombination rate formula for solution to obtain a first electron recombination rate and a first hole recombination rate of the carrier lifetime model; Calculating the continuity equation of the semiconductor based on the first electron recombination rate and the first hole recombination rate to obtain a first functional relationship between current and voltage in the carrier lifetime model; Based on time and the first functional relationship between current and voltage, obtaining a first current-voltage characteristic curve.

3. The method for selecting a model of the photovoltaic device recombination mechanism according to claim 2, characterized in that, The Shockley recombination rate formula is: Among them, np is the recombination behavior of electrons in the conduction band and holes in the valence band, is the distribution of electrons and holes under thermal equilibrium, τ n is the recombination lifetime of electrons, τ p is the recombination lifetime of holes, n + n1 is the sum of the conduction band electron density and the defect state electron concentration, p + p1 is the sum of the valence band hole density and the defect state hole concentration, R n is the electron recombination rate, R p is the hole recombination rate.

4. The method for selecting a model of the photovoltaic device recombination mechanism according to claim 1, wherein The step of calculating the recombination rate for the carrier lifetime model, the discrete defect energy level model, and the continuous defect energy level model respectively based on the finite element simulation method to obtain a first current-voltage characteristic curve of the carrier lifetime model, a second current-voltage characteristic curve of the discrete defect energy level model, and a third current-voltage characteristic curve of the continuous defect energy level model further includes: Substitute the energy level positions of the discrete defects in the discrete defect energy level model into the Fermi–Dirac distribution function for solution to obtain the carrier occupancy probability of the discrete defect energy level model; Based on the carrier occupancy probability, determine the second electron recombination rate, the second hole recombination rate, and the defect charge of the discrete defect energy level model; Calculate the continuity equation based on the second electron recombination rate, the second hole recombination rate, and the defect charge to obtain the second functional relationship between current and voltage in the discrete defect energy level model; Based on time and the second functional relationship between current and voltage, obtain the second current-voltage characteristic curve.

5. The method for selecting a model of the recombination mechanism of a photovoltaic device according to claim 4, characterized in that, The Fermi–Dirac distribution function is: Among them, E t is the defect energy level position, E f is the Fermi energy level, k B T is the thermal energy of the photovoltaic device, k B is the Boltzmann constant, T is the temperature of the photovoltaic device, g D is the defect state degeneracy factor, f t is the carrier occupancy probability.

6. The method for selecting a model of the photovoltaic device recombination mechanism according to claim 1, characterized in that, The step of respectively calculating the recombination rates of the carrier lifetime model, the discrete defect energy level model, and the continuous defect energy level model based on the finite element simulation method to obtain the first current-voltage characteristic curve of the carrier lifetime model, the second current-voltage characteristic curve of the discrete defect energy level model, and the third current-voltage characteristic curve of the continuous defect energy level model further includes: Substitute the continuously distributed defect energy level positions in the continuous defect energy level model into the defect state density function and the Fermi–Dirac distribution function for solution to obtain the defect state density distribution and the occupancy probability of the continuous defect energy level model; Based on the defect state density distribution and the occupancy probability, determine the total defect charge, the third electron recombination rate, and the third hole recombination rate of the continuous defect energy level model; Calculate the continuity equation based on the total defect charge, the third electron recombination rate, and the third hole recombination rate to obtain the third functional relationship between current and voltage in the continuous defect energy level model; Based on time and the third functional relationship between current and voltage, obtain the third current-voltage characteristic curve.

7. The method for selecting a model of the recombination mechanism of a photovoltaic device according to claim 6, characterized in that, The defect state density function is: Among them, N t is the total density of defect states, E t,0 is the central energy level of the defect state density distribution, σ is the standard deviation of the energy level distribution, E t is the defect energy level position, g t (E t ) is the defect state density distribution; The occupancy probability is calculated by the following formula: Among them, E t is the defect energy level position, E f is the Fermi energy level, k B T is the thermal energy of the photovoltaic device, k B is the Boltzmann constant, T is the temperature of the photovoltaic device, g D is the defect state degeneracy factor, f t (E t ) is the occupation probability mentioned above.

8. A model selection system for a photovoltaic device recombination mechanism, characterized in that, The system includes: a data acquisition module, a solution module, and an analysis module; The data acquisition module is configured to: acquire a carrier lifetime model, a discrete defect energy level model, and a continuous defect energy level model. The carrier lifetime model is used to characterize the corresponding relationship between the recombination lifetime of carriers and time in a photovoltaic device. The discrete defect energy level model is used to characterize the corresponding relationship between the energy level positions of discrete defects and carriers in a photovoltaic device. The continuous defect energy level model is used to characterize the corresponding relationship between the continuously distributed defect energy level positions and carriers in a photovoltaic device; The solving module is configured to: respectively calculate the recombination rates of the carrier lifetime model, the discrete defect energy level model, and the continuous defect energy level model based on the finite element simulation method, so as to obtain a first current-voltage characteristic curve of the carrier lifetime model, a second current-voltage characteristic curve of the discrete defect energy level model, and a third current-voltage characteristic curve of the continuous defect energy level model. The first current-voltage characteristic curve is used to characterize the corresponding relationship between current and voltage in the carrier lifetime model, the second current-voltage characteristic curve is used to characterize the corresponding relationship between current and voltage in the discrete defect energy level model, and the third current-voltage characteristic curve is used to characterize the corresponding relationship between current and voltage in the continuous defect energy level model; The analysis module is configured to: obtain the open-circuit voltage of the carrier lifetime model according to the first current-voltage characteristic curve, the open-circuit voltage of the discrete defect energy level model according to the second current-voltage characteristic curve, and the open-circuit voltage of the continuous defect energy level model according to the third current-voltage characteristic curve; select the model corresponding to the maximum open-circuit voltage value as the optimal model for optimizing the performance of the photovoltaic device.

9. An electronic device, comprising: A memory and a processor, characterized in that the processor is configured to implement the steps of a method for selecting a model of a photovoltaic device recombination mechanism according to any one of claims 1-7 when executing a computer program stored in the memory.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that, The computer program, when executed by a processor, implements the steps of a method for selecting a model of a photovoltaic device recombination mechanism according to any one of claims 1-7.

Images