Mingzhe Yu, Xiaoyu Deng, Yanmin Wei, Yueqing Chen, Xi Ge, Hao Liu, Xiyan Tang, Shenghou Zhou, Guang Han, Hao Lin, Yongzhe Zhang, D. He, Hui Yan, Pingqi Gao, Miao Yang, Junxiong Lu, Chaowei Xue, Qiming Liu, Liang Fang, Xixiang Xu
Amorphous silicon (a-Si) passivating contacts enable excellent surface passivation in high-efficiency silicon solar cells, but their high contact resistivity constrains further gains. Nanocrystalline silicon (nc-Si) offers lower resistivity, yet its low deposition rate limits scalability. Here, we demonstrate micron- to submicron-scale selective crystallization of a-Si via laser-induced crystallization (LIC), creating localized low-resistivity regions while retaining high deposition throughput. LIC exploits the interplay of laser irradiation, surface morphology, and thermal diffusion, with nanosecond and picosecond lasers inducing crystallization through distinct heat-transfer mechanisms. Using 532-nm nanosecond and 355-nm picosecond lasers, contact resistivity is reduced by over an order of magnitude. Integrated into a hybrid back-contact solar cell, nanosecond LIC delivers a 0.26% absolute efficiency gain, achieving a certified efficiency of 27.49%. These results establish mixed-phase a-Si/nc-Si films as advanced passivating contacts and highlight LIC as a pathway for precise laser engineering in next-generation silicon photovoltaics.