In Situ Assembly of a Perovskite Photodetector with Broadband Response by Magnetic-Field-Assisted Pulsed Laser...

All-inorganic perovskite quantum dots (IPQDs) are emerging optoelectronic materials for next-generation photodetectors. However, the assembly of IPQDs to photodetectors remains challenging due to the poor controllability of the material deposition processes. Herein, a magnetic-field-assisted pulsed laser deposition (MF-PLD) technology is developed to fabricate CsPbBr₃ perovskite photodetectors with a broadband response. Owing to the focusing effect of the magnetic field, the laser-sputtered CsPbBr₃ plasma plumes are confined into a focused plume beam when passing through a magnetic lens and subsequently in situ assembled to the gaps between two interdigitate electrodes of the photodetector. By controlling the magnetic field strength during MF-PLD, the morphology of the deposited CsPbBr₃ is flexibly manipulated from aggregated large particles to cross-linked nanowire clusters, resulting in the effective control of the optoelectronic properties. The fabricated CsPbBr₃ perovskite photodetectors exhibit a detection range of 265-532 nm, and the relationship between the photodetection performance and the applied magnetic field of MF-PLD was evaluated. The photodetectors fabricated by MF-PLD exhibit improved stability after repeated response-recovery cycles, and their long-term stability is significantly improved through encapsulation, maintaining 85% of the original response after 270 days in air. This work provides a universal strategy to fabricate perovskite-based optoelectronic devices, facilitating the applications of IPQDs.