Multilayered double perovskite ferroelectric for green high-performance self-powered X-ray detection†

Abstract

Layered hybrid perovskite ferroelectrics have made significant strides in high-performance X-ray detection, attributed to their polarization-induced large built-in electric fields and excellent carrier mobility. However, most reported layered hybrid perovskite ferroelectrics rely on environmentally hazardous lead halides, which limits their broader application. Recently developed hybrid double perovskites offer promising alternatives for green self-driven X-ray detection. Herein, we explore the bulk photovoltaic effect in a two-dimensional multilayered double perovskite ferroelectric CHMA₂CsAgBiBr₇ (CCAB, CHMA⁺ = cyclohexylmethylammonium) for self-driven X-ray detection. Due to its multilayer structure, CCAB exhibits a large μτ product of 3.3 × 10⁻³ cm² V⁻¹, which is comparable to the three-dimensional double perovskite Cs₂AgBiBr₆. Specifically, the X-ray detector exhibits a photovoltage of 0.84 V under X-ray irradiation, ensuring the capability to convert X-rays into electric signals without bias. Additionally, CCAB exhibits a high sensitivity up to 120 μC Gy⁻¹ cm⁻² and a low detection limit down to 103 nGy s⁻¹ in the self-driven mode. Our work highlights the potential of lead-free multilayered double perovskite ferroelectrics for achieving high-performance self-driven X-ray detection, paving the way for practical applications of layered hybrid perovskite ferroelectrics in this field.