Cs3Cu2I5 Single Crystal for Efficient Direct X-Ray Detection In article number 2300247, Laishun Qin, Hongsheng Shi, Yanliang Liu, Xue-Feng Yu, and colleagues demonstrate a high-quality Li-doped Cs3Cu2I5 single crystal grown by the Bridgman method that was initially applied as a semiconductor for direct X-ray detection. The Cs3Cu2I5:Li X-ray detector exhibits a high sensitivity of 831.1 µC Gyair−1 cm−2 and low detection limit of 34.8 nGyair s−1, and it reveals a clear outline of the key image in the scanning mode under X-ray excitation.