Slippery Colloidal Crystal Monolayers for Sustainable Enhancement of Commercial Solar Cell Performance

Abstract

The performance of photovoltaic devices can be improved and sustained when their surfaces are designed to increase light absorption of photoactive layers and minimize contaminant adsorption. Pyramid-/domelike surface structures, generally fabricated via etching/lithography, provide these two characteristics to specific solar cells. Colloid-based photonic crystal (PC) monolayers coated on customized cells, without involving special apparatus, are also known for efficiency enhancement. However, to extend the application of PC monolayers to commercial cells, it should be deeply understood first how their photonic characteristics affect light transmittance of thick windows covering the cells. Herein, the PC monolayers on glass/polymer windows (thickness: 0.45-1 mm) are observed to transmit significantly higher amounts of diffuse light at specific visible frequency ranges than bare windows. The frequencies are tuned with the colloid diameter. The results are explained by an electric field distribution study and calculations on the monolayers. The PC monolayers on these windows enhance the short-circuit currents and power conversion efficiencies of commercial amorphous and polycrystalline Si solar cells. Furthermore, strategies are suggested to fix monolayers for structure stabilization and modify their surfaces with a slippery polymer for contaminant slippage; simulated carbon dusty rains slide off the cell surfaces, sustaining the enhanced cell performance.