Electric-field-controlled CVD growth of CsPbBr3 perovskite films for improved photodetection

Abstract

Uncontrolled crystallization of halide perovskites during chemical vapor deposition (CVD) remains a critical barrier to producing high-performance perovskite films for optoelectronics. Herein, an external electric field is introduced during CVD to precisely regulate CsPbBr₃ film growth. Electric-field-assisted growth leads to suppressed instantaneous supersaturation, elevated nucleation energy barriers, and reduced nucleation density, resulting in the formation of uniform, compact films with significantly enlarged grain sizes. These structural improvements yield a lower trap density, enhanced carrier mobility, and reduced non-radiative recombination compared to the untreated samples. Photodetectors constructed with the optimized films have substantially better optoelectronic properties, manifested by a responsivity of about 62 A/W, a specific detectivity surpassing 10¹² Jones, and a broad linear dynamic range of 118 dB. Moreover, they show a −3 dB bandwidth of ∼250 Hz and significantly faster response time, outperforming devices without electric field assistance. The results reveal a scalable and effective strategy to tailor perovskite crystallization by electric field engineering, enabling the fabrication of high-performance optoelectronic devices.