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Abstract A closed-form drain current compact model for amorphous oxide semiconductor (AOS) thin-film transistors (TFTs), including the influence from trapped charges, is presented in this paper. Accounting for both channel and interface trapped charges in this model, we explicitly solve the inherent closed-form surface potential by improving the computational efficiency of the effective charge density approach. Furthermore, based on the explicit solution of the surface potential, the expressions of the trapped and inversion charges in the channel film are derived analytically, and the drain current is integrated from the charge sheet model. Then, for the cases of the different operational voltages, the accuracy and practicability of our model are verified by numerical results of the surface potential and experimental data of the drain current in amorphous In-Ga-Zn-O TFTs, respectively. Finally, we give a discussion about the influence of the interface trapped charges on the device reliability. As a result, the model can be easily to explore the drain current behavior of the AOS TFTs for next-generation display circuit application. Highlights • An inherent closed-form trapped-charge-included drain current compact model of AOS TFTs is derived. • The closed-form surface potential without smoothing function is explicitly solved. • The drain current is derived from the charge-sheet model and validated by experimental data. • Some discussions are gave about the influence from interface trapped charges on the DC properties of AOS TFTs. [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]

Recently, considerable efforts have been made in visual search reranking towards refining initial text-based image search results. In this paper, we propose a hypergraph based semi-supervised ranking method called HyperSSR for image search reranking. According to the basic visual consistency principle that visually similar images should have similar ranking scores, we introduce the hypergraph to capture the intrinsic geometrical structure of the data distribution. To build a robust hypergraph, a novel hypergraph construction approach is developed to incorporate relevance and pseudo relevance degree information from labeled and unlabeled samples, respectively. Based on the premise that a ranking model should work better with the prior pairwise preferences, we jointly incorporate the hypergraph regularizer and the prior pairwise preferences information into a unified ranking learning framework. Experimental results on MSRA-MM 1.0 dataset suggest our proposed approach produces superior performances compared with several state-of-the-art methods. [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]

• We analytically solve some types of lumped-parameter models for solar cells. • We discuss the effects of model parameters on S-shaped I - V characteristics. • Our solution is valid in whole operation regime of solar cells including kink region. • Our scheme increases accuracy and efficiency of simulation and parameter-extraction. In this paper, we propose a method to analytically solve some types of DC lumped-parameter equivalent circuit models for solar cells with S-shaped I - V characteristics measured under illumination. Based on the models proposed previously by other authors, we present the set of equations describing solar cell's terminal current and voltage, derive the analytical solutions of I - V characteristics, and give discussions about the effects from the model parameters on solar cells' I - V characteristics. The comparisons between the proposed solutions and the least square method results illustrate that the solution calculation scheme is not only both accurate and efficient, but also valid in the whole operation regime of solar cells especially for the S-shaped kink in the first quadrant. Finally, the solutions are validated by the reconstructed experimental data to demonstrate that they can be adopted in the practical applications of solar cells. As a result, the feature of the proposed solutions can decrease computation complexity, ease the extraction process of the solar cells' model fitting parameters, and increase simulation accuracy. [ABSTRACT FROM AUTHOR]

Highlights • A lumped-parameter equivalent circuit model of organic solar cells (OSCs) is proposed. • The explicit solution to I - V equation set of the lumped-parameter model is derived. • Our model is suitable to be compactly implemented into computer-aided-design simulations of photovoltaic applications. • We verify the simulation results of our proposed model by using numerical iteration results the experimental data. • We discuss about effects from fitting parameters on I - V characteristics of OSCs. Abstract A lumped-parameter equivalent circuit model of organic solar cells (OSCs) is proposed to analyze the S-shaped current-voltage (I - V) characteristics and the explicit solution to I - V equation is derived so that this model is suitable to be compactly implemented for the simulations of photovoltaic applications. Comparing our explicit solutions with the method of least squares and the Newton-Raphson root-finding scheme, the simulations quantificationally reproduce the S-shaped I - V characteristics of OSCs especially for both linear- and exponential-like S-shaped kink in the third and first quadrants, respectively. Simultaneously, the simulations facilitate us to qualitatively analyze the S-shaped I - V characteristics of OSCs influenced by the different model parameters. Furthermore, we verify the simulation results of our proposed model by using the reconstructed experimental data. Good agreements indicate that such a model can be used to accurately predict the S-shaped I - V characteristics of OSCs and regarded as a serviceable tool implemented compactly into simulations of the wide photovoltaic applications. [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]