Subzero temperature-induced lattice compression enables high carrier mobility in MAPbBr3 single crystals

Abstract

Organic–inorganic hybrid perovskite single crystals exhibit outstanding optoelectronic properties, holding significant promise for next-generation optoelectronic applications. However, their carrier mobility remains limited by conventional growth methods. Herein, we report a strategy to significantly enhance the carrier mobility of CH₃NH₃PbBr₃ single crystals to 541 cm² V⁻¹ s⁻¹ through crystal lattice compression. This was achieved using a freezing temperature growth method, where high-quality CH₃NH₃PbBr₃ single crystals were grown at sub-zero degree Celsius temperature. The induced compressive strain markedly improved the optoelectronic properties, reducing the surface trap density to 3.73 × 10⁷ cm⁻² and extending the carrier lifetime to 15.83 µs. Moreover, lattice compression enabled fine-tuning of the intrinsic band gap from 2.1 eV to 2.24 eV, resulting in photoluminescence peak shift from 555 nm to 520 nm. These findings highlight crystal lattice compression as a powerful strategy to tailor the fundamental properties of perovskite single crystals, offering a pathway toward their integration in high-performance optoelectronic devices.