Interaction Effect between Neighboring Nonperiodic Radial Junctions on Inside Absorption and Photocurrent Distribution

Radial junction (RJ) structures constructed upon silicon nanowire (SiNW) cores have been proven to be an efficient method for fabricating high-performance, flexible thin-film solar cells. Due to the low-melting-point metal catalyzed vapor–liquid–solid (VLS) grown SiNWs, the RJ units are randomly distributed/orientated on the uneven surface of the substrate. However, a comprehensive understanding of the interaction between the neighboring RJ units at nonequivalent sites, which affects light absorption distribution inside, remains unexplored. Herein, a finite-element simulation has been performed, where two RJ units were built at nonequivalent sites in a periodic simulation box, taking SiNW geometric parameters (tilting angle and distance between neighboring units) into account. Evolutions of light absorption, external quantum efficiency curves, and photocurrent are systematically studied, indicating that RJ units with different arrangements usually have different absorption behaviors, which cannot simply be represented by a single RJ model in the periodic simulation box. These results can not only provide a unique perspective in understanding light absorption behaviors inside the randomly distributed RJ units for fabricating high-performance flexible thin-film solar cells but also build a universal platform to investigate the interaction between nonequivalent neighboring units on light absorption and photocurrent generation distribution in nonperiodically nanostructured arrays.