Efficient light-trapping in ultrathin GaAs solar cells using quasi-random photonic crystals

• DOI: 10.1016/j.nanoen.2022.107080
• Publication Date: 2022-02-27T14:26:25Z
• Authors: Jeronimo Buencuerpo; Theresa E. Saenz; Mark Steger; Michelle Young; Emily L. Warren; John F. Geisz; Myles A. Steiner; Adele C. Tamboli
• Keywords: Ray

Ultrathin solar cells reduce material usage and allow the use of lower-quality materials thanks to their one order of magnitude smaller thickness than their conventional counterparts. However, efficient photonic light-trapping is required to harvest the incident light efficiently for an otherwise insufficient absorber thickness. Quasi-random photonic crystals are predicted to have high efficient light-trapping while being more robust under angle and thickness variations than simple photonic crystals. Here we experimentally demonstrate a light-trapping solution based on quasi-random photonic crystals fabricated by polymer blend lithography. We control the average lattice parameter by modifying the spin-coating speed. We demonstrate an ultrathin GaAs cell of 260 nm with a rear quasi-random pattern with submicron features, and a Jsc =26.4 mA/cm2 and an efficiency of 22.35% under the global solar spectrum.