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A parameter extraction routine for three-diode lumped parameter model of organic solar cells (OSCs) based on particle swarm optimization (PSO) is presented in this letter. In the process of parameter extraction by using PSO, we overcome the problem of encountering locally optimal solutions, where such a problem results from the similar effects of some parameters on ${I} - {V}$ characteristics. Combining with the analytical solution algorithm of OSCs’ three-diode lumped parameter model, our parameter extraction routine can efficiently acquire the accurate fitting parameters to complete simulations for ${I} - {V}$ characteristics. Furthermore, this routine is valid for the different algorithms of the solution to OSCs’ ${I} - {V}$ properties. Finally, we use the experimental data measured from OSCs to verify the parameter extraction routine. As a result, such a parameter extraction routine can perform as an important tool to extract the fitting parameters of OSCs’ lumped parameter model. [ABSTRACT FROM AUTHOR]

A lumped-parameter equivalent circuit model is proposed to simulate the S-shaped current–voltage (${I}$ – ${V}$) characteristics exhibited in organic solar cells. First, we derive an explicit terminal current solution as a function of terminal voltage from the equation set of the three-diode lumped-parameter model proposed by Mazhari. Second, we improved Mazhari’s model to improve the accuracy and developed the explicit solution of our improved model to improve the efficiency. Third, we use the method of least squares, Newton–Raphson root-finding scheme, and experimental data to validate the solutions of Mazhari’s and our models. As a result, owing to high accuracy and efficiency of computation, our explicit calculation scheme, regarded as a useful tool, can help to implement Mazhari’s and our models into photovoltaic device and system simulators in compact format. [ABSTRACT FROM AUTHOR]

We propose an improved lumped-parameter equivalent circuit model to describe S-shaped I–V kinks observed from organic solar cells. Firstly, to predict the S-shaped I–V kinks accurately in both the first and fourth quadrants, a shunt resistor in parallel with extraction diode is added to our previous model. Secondly, based on the Newton–Raphson method, we derive a solution to our improved circuit. Thirdly, our solution is verified by the method of least squares and experiments. Finally, compared with our previous work, the improved circuit has higher accuracy in demonstrating S-shaped I–V kinks in the first and fourth quadrants. Such an improved model is suitable for circuit simulations of organic solar cells. [ABSTRACT FROM AUTHOR]

An explicit parameter-extraction method is proposed to estimate the values of fitting parameters in lumped-parameter equivalent circuit model of industrial solar cells. The explicit method is based on polynomial fitting curves on Matlab platform, TCAD device simulation results of Silvaco Atlas, and experimental data of silicon-based solar cells' current-voltage characteristics. Such an explicit parameter-extraction method can be directly applied into the analytical solutions to one-diode lumped-parameter equivalent circuit model to complete the simulations for electrostatic properties of solar cells. First, the current-voltage characteristics of industrial silicon-based solar cells are also derived analytically as the previous works completed by other researchers and the four key factors especially for the maximum power formula are solved through the effective diode approach. Second, polynomial curve is used to fit current-voltage characteristics from simulation and experiment results of solar cells under illumination. Third, the polynomial fitting result, the short circuit current, and the open circuit voltage are used to extract explicitly all of five parameters included in the one-diode lumped-parameter equivalent circuit model for industrial solar cells. Finally, the extracted fitting parameters are substituted into the analytical solution to current-voltage characteristics and the obtained current-voltage characteristics are compared with device simulation results from Silvaco Atlas and experimental data from silicon-based solar cells. As a result, such an explicit extraction procedure could be regarded as a fast and accurate method to estimate model parameters in industrial solar cells, which is important for not only photoelectric device simulations but also process analysis. • An explicit parameter-extraction strategy with clear device physical significance is proposed. • This strategy can simulate I-V characteristics of solar cells accurately and efficiently. • We propose effective diode approach to solve the maximum power point of industrial solar cells. [ABSTRACT FROM AUTHOR]

• The regional approach is used to solve F. J. García-Sánchez's model analytically. • An accurate and efficient reproduction of S-shaped I-V characteristics is provided. • Model parameters' effects are analyzed and verified by Numerical iteration results. • Reconstructed experimental data are used to validate practicability of analytical solution. In this paper, an analytical solution to three-diode lumped-parameter equivalent circuit model is proposed to simulate and present S-shaped I-V characteristics of next generation solar cells, which are observed frequently in perovskite and organic solar cells, and occasionally in other kinds of solar cells. In general, because complicated transcendental equation includes three exponent items resulting from three diodes, the absence of an analytical solution has become a bottleneck that limits the adoptions of solar cells' three-diode lumped-parameter model into practical applications and device simulations. To break through the above bottleneck, the analytical solution is derived in the regional approach, completed in Matlab platform, and verified by reconstructed experimental data measured from real solar cells. Such an analytical solution processes the key feature with high precise and efficiency. High precise results from the mathematical operations of the analytical solution to lumped-parameter model and high efficiency results from the avoidance of numerical iteration methods. In addition, this analytical solution facilitates researchers to accurately determine short circuit current and open circuit voltage, quickly extract model parameters in lumped-parameter circuit, and in detail assess effects from model parameters on DC characteristics of solar cells. Finally, the proposed analytical solution is able to be used to reproduce S-shaped I-V characteristics of solar cells, assist in extracting fitting parameters in three-diode lumped-parameter equivalent circuit model, and complete implementation of model into semiconductor device and circuit simulators. [ABSTRACT FROM AUTHOR]

In order to analyze and optimize new generation solar cells' electrostatic performances, lumped-parameter equivalent circuit model is a common method to simulate S-shaped I – V characteristics including linear, exponential, or exponential-like current kinks. Unfortunately, three-diode lumped-parameter model is still inevitable to be solved generally in numerical iteration method. The absence of explicit solution to three-diode lumped-parameter model is actually the main bottleneck of implementing the model into photovoltaic device and circuit simulators in compact. In this paper, to overcome the problem of three-diode model's implementation into simulators, we proposed an explicit solution to the model based on the regional approach, where high accuracy and low computation time cost are the main features of such a solution. Analytical derivation and correction for the solution to transcendent I – V equation in three-diode model leads to high computation accuracy, and avoidance of numerical iteration methods introduces low computation time cost. Finally, numerical iteration results and reconstructed experimental data of solar cells are used to validate the accuracy and applicability of our proposed explicit solution. As a result, high accuracy and efficiency of the explicit solution make it possible to implement three-diode lumped-parameter equivalent circuit model into photovoltaic device and circuit simulators and explain I – V characteristics of new generation solar cells. • P. J. Roland's model is analyzed as a synthesis of one-, two-, and three-diode models. • The explicit solution is derived to solve P. J. Roland's model. • S-shaped I–V characteristics with current kinks are reproduced accurately and efficiently. • Numerical iteration results are used to quantify and analyze the errors. • Reconstructed experimental results are used to validate practicability of explicit solution and model. [ABSTRACT FROM AUTHOR]