25 cm²-Sized Glass-Like Transparent Crystalline Silicon Solar Cells with an Efficiency of 14.5%

Forming light-transmitting structures on c-Si photovoltaics to transmit visible light without wavelength dependency is a promising strategy to realize neutral-color transparent c-Si photovoltaics (c-Si TPVs). However, dry etching, which is used to form a light-transmitting structure on c-Si, inevitably causes nanoscale surface damages such as scallops and plasma-induced damage in c-Si. This aggravates carrier recombination, which decreases the power conversion efficiency (PCE) of c-Si TPVs. Here, we propose an effective chemical treatment method for removing nanoscale surface damage from c-Si microholes. A large-sized neutral-color c-Si TPV after the chemical treatment exhibited a high PCE of 14.5% at a transmittance of 20%. The chemical treatment also enabled systematic control of the hole size (167 nm/sec), and thus, the transmittance was easily tuned from 10% to 70%. Notably, the proposed chemical treatment satisfies the three development factors of 1) high PCE, 2) scaling up, and 3) easy light transmittance tuning of c-Si TPVs.