Low ion migration and defect density MAPbX3 single crystals grown at low temperature for X-ray detection

Abstract

Defects and the ion migration in perovskite single crystals seriously degrade the performance of corresponding devices, regardless of the outstanding optoelectronic properties. In this work, we demonstrated that the ion migration and the defect density in MAPbX₃ perovskite single crystals can be suppressed via lowering the growth temperature to 4 °C (LT) of the liquid-diffusion induced crystallization method (LDSC). The MAPbBr₃ single crystals grown with the LT-LDSC method demonstrated a full-width at half-maximum (FWHM) of the (100) X-ray rocking curves of 0.0104°, a fluorescence lifetime of 1090 ns, a trap state density of 3.03 × 10⁹ cm⁻³, an ionic activation energy of 0.52 eV, and a μτ product of 3.22 × 10⁻² cm² V⁻¹. The low defect density and the weak ion migration in MAPbX₃ single crystals lead to good X-ray detection performance under higher bias voltage. The X-ray detector has a high sensitivity of 409 μC Gy_air⁻¹ cm⁻² at a high bias voltage of −40 V, which is the highest bias voltage of this single crystal radiation detector. This method of low temperature growth is instructive to the study of the whole crystal growth.