ANALYTICAL MODEL OF THIN-FILM SILICON SOLAR CELL

There is an important need for improvement in both cost and efficiency of photovoltaic cells. For improved efficiency a better understanding of solar cell performance is required. In this paper we propose an analytical kinetic model of thin-film silicon solar cell, which can provide an intuitive understanding of the effect of illumination on its charge carriers and electric current. The separate cases of homogeneous and inhomogeneous charge carrier generation rates across the device are investigated. Our model also provides for the study of the carrier transport within the quasi-neutral and depletion zones of the device, which is of importance for thin-film solar cells. Two boundary conditions based on (i) fixed surface recombination velocity at the electrodes and (ii) intrinsic conditions for large size devices are explored. The device short circuit current and open circuit voltage are found to increase with the decrease of surface recombination velocity at electrodes. The power conversion efficiency of thin film solar cells is observed to strongly depend on impurity doping concentrations. The developed analytical kinetic model can be used to optimize the design and performance of thin-film solar cells without involving highly complicating numerical codes to solve the corresponding drift-diffusion equations.