Suppression of ion migration in lead-free zero-dimensional perovskite FA3BiBr6 single crystals for X-ray detection

Abstract

In recent years, there has been significant interest in addressing the issue of ion migration in perovskite materials. One recognized and effective solution is to reduce the dimensionality of perovskites. While most studies have focused on quasi-two-dimensional (quasi-2D) perovskites or the introduction of two-dimensional (2D) heterojunctions into three-dimensional (3D) perovskites, less attention has been given to zero-dimensional (0D) perovskites. As a low-toxicity bismuth-based perovskite, our research direction is centered on exploring the seldom-investigated A₃BiX₆ 0D structure. In this study, we present the successful growth of high-quality C₃H₁₅N₆BiBr₆ (FA₃BiBr₆) perovskite single crystals (PSCs) on a centimeter scale using a straightforward solution evaporation method (SE). The FA₃BiBr₆ PSCs exhibit a low trap density of 2.22 × 10⁹ cm⁻³ and a high carrier mobility–lifetime product (μτ) of 1.24 × 10⁻⁵ cm² V⁻¹ as well as a high resistivity of 1.475 × 10¹⁰ Ω cm. The X-ray detector shows a high sensitivity of 231 μC Gy_air⁻¹ cm⁻², a low detection limit of 460 nGy_air s⁻¹ and a low baseline drift of 3.73 × 10⁻⁴ pA cm⁻¹ s⁻¹ V⁻¹.