Although three-dimensional metal halide perovskite (ABX3) single crystals are promising next-generation materials for radiation detection, state-of-the-art perovskite X-ray detectors include methylammonium as A-site cations, limiting the operational stability. Previous efforts to improve the stability using formamidinium–caesium-alloyed A-site cations usually sacrifice the detection performance because of high trap densities. Here we successfully solve this trade-off between stability and detection performance by synergistic composition engineering, where we include A-site alloys to decrease the trap density and B-site dopants to release the microstrain induced by A-site alloying. As such, we develop high-performance perovskite X-ray detectors with excellent stability. Our X-ray detectors exhibit high sensitivity of (2.6 ± 0.1) × 104 μC Gyair−1 cm−2 under 1 V cm−1 and ultralow limit of detection of 7.09 nGyair s−1. In addition, they feature long-term operational stability over half a year and impressive thermal stability up to 125 °C. We further demonstrate the promise of our perovskite X-ray detectors for low-bias portable applications with high-quality X-ray imaging and monitoring prototypes.

Designing high-performance bifunctional oxygen evolution/reduction reaction (OER/ORR) catalysts is a newly emerged topic with wide applications in metal-air batteries and fuel cells. Herein, we report a group of (27) single-atom...

Two-dimensional (2D) transition-metal carbides (MXenes) as electrode materials have attracted much attention because of their excellent energy storage properties and electrical conductivity. In this work, we study the properties of the V3C2 MXene anode for metal-ion (Li, Na, K, and Ca) batteries by means of density functional theory computations. Based on our calculated results, V3C2 exhibits excellent properties such as structural stability, good electrical conductivity, fast charge–discharge rates, and high theoretical storage capacity. In particular, owing to its low diffusion barrier (0.04 eV for Li, 0.02 eV for Na, 0.01 eV for K, and 0.04 eV for Ca) and high storage capacity (606.42 mA h g–1 for both Li and Na, 269.86 mA h g–1 for K, and 539.71 mA h g–1 for Ca), V3C2 monolayers are predicted to be promising anode materials especially for lithium-ion batteries and sodium-ion batteries. Our work provides a new avenue for the design of novel 2D materials for energy applications.

Despite having attractive stability over the volatile methylammonium (MA) cation, double-cation (Cs, FA) perovskite solar cells are largely overlooked because of their inferior performance compared to MA-based devices. Among all the device engineering strategies, surface passivation represents a promising approach to acquire improved performance. However, effective passivation strategies have not yet been developed for attaining efficiencies of MA-free cells close to their theoretical limit. Herein, fullerene passivators with different binding groups are investigated to establish relationships between molecule structure and perovskite surface properties. It is found that surface treatment with bis-fulleropyrrolidium iodide (bFPI) can have strong interaction with charged defects, leading to effective defect passivation and favorable band-bending at the interface. The resulting bFPI-treated device shows significantly reduced defect density as well as accelerated electron extraction from perovskite into the cathode. Consequently, the MA-free device exhibits an efficiency of 21.1% with long-term environmental stability.