Solution-phase, template-free synthesis of PbI₂ and MAPbI₃ nano/microtubes for high-sensitivity photodetectors

Organic-inorganic hybrid perovskite materials with exotic semiconducting properties have become inevitable candidates for next-generation electronic devices. Very recently, a low dimensional nanostructure of the perovskite materials has attracted the scientific community due to its enhanced performance in optoelectronics as compared to its bulk counterparts. Herein, a facile method was developed for the scalable, room-temperature synthesis of CH3NH3PbI3 (MAPbI3) nano/microtubes by direct conversion of lead iodide (PbI2) microtubes through a solution-phase method. At first, the PbI2 microtubes were synthesized by the anti-solvent crystallization process and subsequently converted to CH3NH3PbI3 nano/microtubes by the addition of CH3NH3I (MAI) precursor directly in the solution phase. The corresponding photodetectors (PDs) in the lateral metal-semiconductor-metal (MSM) configuration of the PbI2 microtubes and MAPbI3 nano/microtubes on glass substrates were investigated systematically. Compared to the PbI2 based PDs (557 mA W-1, 3.65 × 1012 Jones, 0.251 s/0.252 s), the MAPbI3 based PDs exhibit higher photoresponsivity, specific detectivity, and faster response time (25 A W-1, 9.9 × 1013 Jones, 49 ms/20 ms) under irradiation with 4.6 μW cm-2 intensity light of the 532 nm laser at a bias of 5 V. The proposed method is a low-temperature process, easy to apply in large scale synthesis, and finds potential applications in optoelectronic devices.