A lead-free halide hybrid perovskite (TMHD)BiCl5 for ultraviolet photodetection

Abstract

Lead halide hybrid perovskites with a wide bandgap (e.g., CH₃NH₃PbCl₃) have gained tremendous attention in the field of ultraviolet (UV) photodetection due to their brilliant optoelectronic activity. Although the environment-unfriendly nature of lead in these hybrids is unfavorable for their wide-scale application. Exploring lead-free halide hybrid semiconductors for high-performance ultraviolet photodetection is extremely important. In this work, a new broadband lead-free hybrid perovskite (TMHD)BiCl₅ (TMHD = N,N,N,N-tetramethyl-1,6-hexanediammonium) is successfully prepared through a facile solution process. A low trap density of 8.2 × 10¹⁰ cm⁻³ and a high carrier mobility of 0.62 cm² V⁻¹ s⁻¹ contribute to the charge transport properties. Furthermore, lateral UV photodetectors based on high-quality lead-free (TMHD)BiCl₅ single crystals are fabricated for the first time, which show considerable on/off current ratios (>10³) and a prominent photoresponsivity (8.8 mA W⁻¹) under 266 nm irradiation. We anticipate that this study will provide new inspiration for designing broadband lead-free hybrids for promising UV optoelectronic applications.