Reductant Engineering in Stable and High‐Quality Tin Perovskite Single Crystal Growth for Heterojunction X‐Ray Detectors

Abstract

Tin perovskites have emerged as a promising alternative material to address the toxicity of lead perovskites and the low bandgap of around 1.1 eV is also compatible with tandem solar cell applications. Nevertheless, the optoelectronic performance of solution‐processed tin perovskite single‐crystal counterparts still lags behind because of the tin instability under ambient conditions during crystal growth and limited reductants to protect the Sn2+ ions from oxidation. Here we study the reductant engineering to grow high‐quality tin perovskite single crystals under ambient conditions. Oxalic acid (H2C2O4) serves as an excellent reductant and sacrificial agent to protect Sn2+ ions in methanol due to its suitable redox potential of ‐0.49 V, and the CO2 as the oxidation product in the gas state can be easily separated from the solution. The FPEA2SnI4 single crystal grown by this strategy exhibits low trap density perovskite surface by constructing an FPEA2PbI4‐FPEA2SnI4 single crystal heterojunction for X‐ray detection. An improved X‐ray sensitivity of 1.7×105 μC Gy−1 cm−2 is realized in the heterojunction device, outperforming the control FPEA2PbI4 counterpart.This article is protected by copyright. All rights reserved

Passivation Effect of CsPbBr3 Films Based on SnBr4 Post-Treatment

“…Metal halide-based hybrid perovskites have become a promising material for photovoltaic applications due to their tunable band gap, long carrier diffusion distance, and high absorption coefficient . Consequently, they have garnered extensive attention and application in the fields of solar cells, LEDs, and photodetectors. − Perovskite solar cells (PSCs) have attracted significant attention due to their high power conversion efficiency (PCE) and low manufacturing cost. ,,− Inorganic perovskite CsPbBr 3 has shown remarkable stability against moisture, oxygen, and heat, resulting in increased interest in recent years. It possesses significant potential for use in tandem solar cells and translucent solar cells. − …”

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

“…5 To date, most of the progress made in direct-type X-ray detectors has been achieved using single crystals. 6–9 However, to meet the demands of practical imaging applications, large single crystals and fine slicing processes are necessary to fabricate detector arrays, which are both challenging and expensive for scalable fabrication. In contrast, directly printing perovskite films onto thin-film transistor (TFT) backplanes is a much easier way to fabricate X-ray flat-panel detectors.…”

Preferred Orientation and Phase Distribution of Quasi-2D Perovskite for Bifunctional Light-Emitting Photodetectors

“…The trap density of states (tDOS) of the LEPDs was measured by employing the thermal admittance spectroscopy (TAS) technique, as shown in Figure d. The reduced trap density of the target film proves that solvent composition and antisolvent engineering have optimized the film quality . Afterward, we characterized the dark current density of the LEPDs, as shown in Figure e.…”