Enhancing Efficiency of InGaN Nanowire Solar Cells by Applying Stress

Abstract

In photovoltaic solar cells, p-n junctions have been considered a very promising structure to improve the carrier collection efficiency and accordingly the conversion efficiency. The basic processes for a solar cell to work are the generation of electron–hole pairs, separation, and recombination of those carriers in external circuits. The step of critical importance here is the electron–hole pair separation. The inner piezopotential, formed in the crystal by applying a stress which is called piezophototronic effect, interferes directly in the separation and recombination process, and consequently affects the solar cell performance. Recently, elaborated models including the piezophototronic effect were proposed to simulate metal/semiconductor and a p-n junction based in ZnO, but discussion of results has been limited to the output and the open-circuit voltage. In the present work, we will attempt to extend systematically the modeling of photovoltaic conversion on solar cell. The piezophototronic effect is included both in transport equation and photocurrent. Finally, the experimental results of organic solar cells support our theoretical model. Using the piezoelectric effect created by external stress, our study not only provides the first basic theoretical understanding about the piezophototronic effect on the characteristics of an inorganic solar cell, but also assists the design for higher performance solar cells.