A solution to the fabrication of amorphous Ga2O3 solar‐blind photodetectors on rigid and flexible substrates at room temperature is reported. A robust improvement in the response speed is achieved by delicately controlling the oxygen flux in the reactive radio frequency magnetron sputtering process. Temporal response measurements show that the detector on quartz has a fast decay time of 19.1 µs and a responsivity of 0.19 A W−1 as well, which are even better than those single crystal Ga2O3 counterparts prepared at high temperatures. X‐ray photoelectron spectroscopy and current–voltage tests suggest that the reduced oxygen vacancy concentration and the increased Schottky barrier height jointly contribute to the faster response speed. Amorphous Ga2O3 solar‐blind photodetector is further constructed on polyethylene naphthalate substrate. The flexible devices demonstrate similar photoresponse behavior as the rigid ones, and no significant degradation of the device performance is observed in bending states and fatigue tests. The results reveal the importance of finely tuned oxygen processing gas in promoting the device performance and the applicability of room‐temperature synthesized amorphous Ga2O3 in fabrication of flexible solar‐blind photodetectors.

MXenes are attracting much attention as electrode materials due to their excellent energy storage properties and electrical conductivity, and the energy storage capacities were found to strongly depend on the surface terminal groups. Here S-functionalized TiC as a representative MXene material is designed. Our density functional theory (DFT) calculations are performed to investigate the geometric and electronic properties, dynamic stability, and Na storage capability of TiC, TiCO and TiCS systems. The TiCS monolayer is proved to show metallic behavior and has a stable structure, and meanwhile it also exhibits a low diffusion barrier and high storage capacity (up to TiCSNa stoichiometry) for Na ion batteries (NIBs). The superior properties such as good electrical conductivity, fast charge-discharge rates, low open circuit voltage (OCV), and high theoretical Na storage capacity, make the TiCS monolayer a promising anode material for NIBs compared to the TiCO monolayer. More importantly, similar to the TiCS monolayer, other MXenes with a high charge density difference and suitable lattice constant can be formed, and thus the energy storage properties are worth further study. This finding will be useful to the design of anode materials for NIBs.