Random Micro-Pyramids for Transparent c-Si Solar Cells: Enabling 16.1% Efficiency with Wavelength-Independent 20% Transmittance

Abstract

Transparent photovoltaics (TPVs) hold immense promise for applications where aesthetic appeal and functional performance align, such as building-integrated photovoltaics. Among TPV technologies, crystalline silicon (c-Si) TPVs have emerged as a leading candidate owing to their glass-like transparency, high efficiency, and long-term stability. However, their overall performance is limited by light loss in transparent regions, which necessitates strategies to maximize light absorption in the active c-Si areas. In this study, a straightforward yet effective approach is presented to enhance light absorption in c-Si TPVs by forming random micro-pyramid structures on the c-Si surface via a simple wet-chemical process. These surface structures significantly improve light absorption without compromising visual transparency. This improvement translates into record short-circuit current density (JSC) of 32.7 mA cm−2 for a 1 cm2 device. When scaled up to a 25 cm2 device, the JSC further increases to 33.3 mA cm−2, achieving an efficiency of 16.1%, which is the highest reported value to date for neutral-colored TPVs with an average visible transmittance (AVT) of 20%. These results demonstrate a scalable and cost-effective method to advance TPV performance, paving the way for broader commercial applications of high-efficiency, transparent solar technologies.