Printable thick junction-based lead-free perovskite single crystal powders for X-ray detection

Abstract

Blade-coating technology is regarded as a pivotal approach for the scalable fabrication of perovskite-based devices and holds great promise for the future manufacturing of advanced X-ray flat-panel detectors. However, further developments face challenges in balancing absorption thickness and charge collection efficiency. Uneven perovskite thick films along the printing direction and unavoidable pinholes are detrimental to carrier transport and greatly limit device performance. Additionally, any high-temperature or high-pressure treatment process is not conducive to the subsequent integration of X-ray detectors, while excessive use of lead-containing perovskites and toxic solvents poses harm to the environment. Presented herein is a strategy utilizing green solvents and organic molecular binders to assist in the crystallization of lead-free perovskite thick films. The prepared Cs₂AgBiBr₆ suspension can be uniformly imprinted onto various substrates at a low temperature. During crystallization, the volatile solvent rapidly evaporates from wet films, forming high-density nuclei. Furthermore, introducing organic molecular binders into the precursor significantly enhances the carrier mobility and structural integrity of the film. As a result, the fabricated X-ray detector achieves a superior sensitivity of 675 μC Gy_air⁻¹ cm⁻². Low noise current and reduced dark current drift also enable a noteworthy detection limit of 11.2 nGy_air⁻¹. This work demonstrates a promising method for fabricating advanced lead-free perovskite X-ray detectors.