Assessment of the light-trapping potential of nanowrinkle textures for enhanced photovoltaic performance

Abstract

Commercially feasible self-assembly nanofabrication methods are used to create quasiperiodic nanotexture designs for thin-film solar cells to improve effective light-trapping. In this work, experimental and theoretical methods were used to study the structure, light-trapping capability, and device performance in amorphous silicon solar cells deposited on four distinct quasiperiodic nanowrinkle substrates. The best device showed 9.46 % power conversion efficiency with ∼36 % improvement in short-circuit photocurrent density compared to its flat counterpart. Confocal micro-Raman spectroscopy was used to ascertain the degree of light-trapping obtainable from a particular nanotexture. Further, device modeling studies elucidate the effects of variations in layer properties arising from surface irregularities, showing that crowding nanofeatures leads to low fill factors from the increased defects, affecting the apparent doping. The correspondence obtained between the fill factor, autocorrelation length, and recombination rate helps to determine the quality of the material that grows on a particular nanowrinkle surface.