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As a key to simulate electrostatic characteristics of solar cells and implement single-diode model into simulators, a noniterative parameter-extraction method is proposed to determine five parameters of single-diode model. It is straightforwardly derived from the transcend equation set of terminal ${I} - {V}$ equations to overcome the imperfections of poor efficiency in numerical iteration methods, low accuracy in semiempirical approaches, and absence of physical meaning in optimization algorithms. As a result, such a parameter-extraction method actually serves as a useful tool to acquire model parameters, analyze preparing process’ results, and expand practicability of lumped parameter model. [ABSTRACT FROM AUTHOR]

Three-diode lumped-parameter equivalent circuit model conforms to photovoltaic device physics and processes an exact analysis for I – V characteristics of industrial solar cells, because it explains the different leakage current components especially for recombination current resulting from defects or grain boundaries. However, three-diode model’s complete circuit topology leads to complicated transcendental I – V equation without analytical solution so that low computation efficiency limits three-diode model’s applications in photoelectric simulations. In this article, an effective-diode method is proposed to simplify three-diode model, derive accurate and efficient terminal current–voltage solution to three-diode model, and acquire electrostatic characteristics of the solar cells. The calculated values have good agreements with numerical iteration results and experimental data measured from solar cells, respectively. Finally, the effective-diode method performs an important role of solving three-diode model analytically, predicting I – V characteristics of industrial solar cells accurately, and providing three-diode model’s practicability and development in solar cells’ simulations. [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]

An analytical surface-potential-based drain current model of dynamic-depletion (DD) polysilicon (poly-Si) thin-film transistors (TFTs) is proposed in this paper. In the 1-D Poisson equation, total charge density is reformulated by an effective charge density, which allows a closed-form surface potential calculation scheme. Different boundary conditions between partial depletion and full depletion are calculated and unified into one back-gate potential in the DD mode, which allows a unified-form surface potential calculation scheme. Combining with Gauss’s theory, we explicitly solve a closed- and unified-form surface potential of DD poly-Si TFTs. Based on the solution of the surface potential, the drain current is derived analytically from the Pao–Sah integration. Furthermore, our solution is verified by numerical results and experimental data, respectively. As a result, such a model can accurately predict I–V characteristics of DD poly-Si TFTs and provide computational efficiency for TFT process optimization and circuit simulations. [ABSTRACT FROM AUTHOR]

We propose an explicit surface-potential-based direct current (dc) model for fully depleted polysilicon (poly-Si) thin-film transistors (TFTs). Being analytical and explicit, the proposed model is a solid base for compact models of these devices. The essential for our model is the explicit calculation of the surface potential, using the Lambert W function. Subsequently, using the surface potential, we also develop the expressions for charge and current, employing well established approaches, which include integration of carrier’s charge for drain current. Furthermore, the solutions of surface potential and drain current were validated by numerical results and experimental data, respectively. Finally, we discussed in detail about the effects on the surface potential and dc properties from the full depleted poly-Si TFT parameters. As a result, such a model is suitable to be implemented into computer-aided simulations of both device and circuit designs, due to its high computational accuracy and efficiency. [ABSTRACT FROM AUTHOR]