Deep metal-assisted chemical etching using a porous monolithic AgAu layer to develop neutral-colored transparent silicon photovoltaics

Here, we report deep metal-assisted chemical etching (MACE) using a porous monolithic AgAu layer on crystalline silicon (c-Si) as an alternative to the expensive deep reactive ion etching (DRIE) for fabricating neutral-colored transparent crystalline silicon photovoltaics (c-Si TPV). To prevent the uneven etching of c-Si by Ag particles, a porous monolithic Ag layer is developed by introducing acetonitrile to enhance the interaction between the c-Si surface and Ag precursor. This results in cooperative motion during MACE, as confirmed by microscopic observation, surface area measurements, and computational simulations. The durability of this Ag catalyst can be further improved by passivation with Au via galvanic replacement (i.e., the porous monolithic AgAu layer), thereby preventing indiscriminate defect generation. Thus, the fabricated c-Si TPV using MACE and a porous monolithic AgAu layer exhibits a high performance of 13.0% with 20% neutral-colored transparency, representing results superior to those obtained with samples fabricated by DRIE (11.5%).