Pressure Regulation of the Lone‐Pair 5 s ² Electrons in Metal Phosphorous Chalcogenides SnPS ₃ for Enhanced Photoelectric Effect

ABSTRACT Lone‐pair n s ² electrons play a key role in designing high performance optoelectronic semiconductors, such as metal phosphorous chalcogenides (MPChs), for photoelectric detection technologies. However, how to regulate lone‐pair n s ² electrons for superior properties attracts wide attention and are still major concerns for MPChs. Herein, we presented a lone‐pair‐electron regulation strategy to significantly enhance the photoelectric properties of SnPS ₃ by pressure‐induced overlapping of lone‐pair electrons of Sn ²⁺ and non‐bonding electrons of S ²⁻ . As a result, the photocurrent density, responsivity, and external quantum efficiency of the SnPS ₃ material were strikingly improved by five orders of magnitude compared to those at ambient pressure. A synergistic theoretical and experimental characterizations indicate that pressure triggers the overlapping of lone‐pair 5 s ² electrons of Sn ²⁺ and non‐bonding electrons of sulfur, resulting in a hybrid orbital transition instead of a p‐p orbital transition, which results in high light absorption capability and low effective mass, and thus better photoelectronic properties. These findings provide an effective pressure engineering strategy to optimize the performance of photodetectors by regulating lone‐pair n s ² electrons and highlight the potential of Sn instead of Pb for the development of advanced photoelectric devices.