Direct Ink Writing of Single-Crystal-Assembled Perovskite Thick Films for High-Performance X-ray Flat-Panel Detectors

Halide perovskites hold great potential in developing next-generation X-ray detectors. However, preparing high-quality and thick perovskite films in a way compatible with a thin-film transistor (TFT)-integrated X-ray flat-panel detectors (XFPDs) remains challenging. Here, by engineering ink with effective printability and shape fidelity, direct ink writing (DIW) is developed as a new approach to printing a unique single-crystal-assembled perovskite (SCAP) thick film. In contrast to polycrystalline grains consisting of randomly orientated crystal domains, the SCAP is made of tightly packed crystals with well-defined crystal facets, showing 3–4 orders of magnitude lower trap density (4.48 × 10 12 cm −3 ). Consequently, the SCAP X-ray detectors offers the state-of-the-art detection performance (sensitivity-to-dark current ratio: 1.26 × 10 11 µC Gy air −1 A −1 ), a low detection limit (114.2 nGy air s −1 ), and negligible baseline drift (0.27 fA cm −1 s −1 V −1 ). Furthermore, the XFPD based on a 64 × 64 pixelated TFT array realizes high-resolution digital radiography, opening a new avenue for further development of perovskite X-ray detectors.