Tianqi Zhang, Yaqi Hou, Jinghui Han, Depeng Chu, Xiang Chen, Guolong Chen, Xiaotong Fan, Xiao Yang, Renzhu Zhang, Yue Zhao, Qingsen Zeng, Yucheng Liu, Shuli Wang, Haotong Wei, Zhong Chen, Yue Lin, Tae-Woo Lee
Achieving environmentally sustainable synthesis of high-quality metal halide perovskite single crystals (MHP-SCs) is critical for advancing next-generation optoelectronic devices. The constrained solvent choices within the green chemistry framework pose a significant challenge to the fine control of crystallization pathways required for the growth of perfect MHP-SCs. Here, we introduce a new paradigm for crystallization control based on steric hindrance engineering using a quantitatively validated green solvent system with high GlaxoSmithKline green solvent scores. We demonstrate that the steric bulkiness of solvent molecules, rather than donor number alone, plays the dominant role in governing the coordination strength between Pb2+ and solvent, thereby regulating precursor complex stability and crystallization kinetics. Finely tuned steric environments promote the unprecedented fast growth of MAPbI3 SCs with a record-low trap density (2.56 × 108 cm-3) and narrowest x-ray diffraction linewidth of 0.00802° (28.9″). These defect-suppressed MAPbI3 SCs enable photodetectors with an ultrahigh specific detectivity of 6.8 × 1013 Jones and x-ray detectors with a low detection limit of 3.6 nGyair s-1. The steric hindrance engineering strategy proves universal across perovskite compositions. This work establishes a sustainable, scalable platform for the growth of high-quality MHP-SCs using quantitatively green solvents.