The study by researchers from University of New South Wales and Jolywood (Taizhou) Solar Technology Co., Ltd reported that parasitic absorption in the rear polysilicon layer of bifacial TOPCon cells reduced short-circuit current density and efficiency. It examined a local thinning method combining ultraviolet picosecond laser treatment with alkaline etching to reduce these optical losses. Laser exposure formed a thin silicon oxide layer that acted as an etch barrier, enabling selective retention of thicker polysilicon regions while untreated areas were thinned. The process reduced parasitic absorption while maintaining passivation performance. Laser processing modified the polysilicon structure, followed by recrystallization with higher doping after firing. Electrical measurements showed incremental gains in current density, open-circuit voltage, and absolute efficiency under one-sun conditions. Device simulations supported the experimental results and indicated further efficiency potential under optimized contact and passivation assumptions.