Passivated Single-Crystalline CH 3 NH 3 PbI 3 Nanowire Photodetector with High Detectivity and Polarization Sensitivity.

Photodetectors convert light signals into current or voltage outputs and are widely used for imaging, sensing, and spectroscopy. Perovskite-based photodetectors have shown high sensitivity and fast response due to the unprecedented low recombination loss in this solution processed semiconductor. Among various types of CH3 NH3 PbI3 morphology (film, single crystal, nanowire), single-crystalline CH3 NH3 PbI3 nanowires are particularly interesting for photodetection because of their reduced grain boundary, morphological anisotropy, and excellent mechanical flexibility. The concomitant disadvantage associated with the CH3 NH3 PbI3 nanowire photodetectors is their large surface area, which catalyzes carrier recombination and material decomposition, thus significantly degrading device performance and stability. Here we solved this key problem by introducing oleic acid soaking to passivate surface defects of CH3 NH3 PbI3 nanowires, which leads to a device with much improved stability and unprecedented sensitivity (measured detectivity of 2 × 1013 Jones). By taking advantage of their one-dimensional geometry, we also showcased, for the first time, the linear dichroic photodetection of our CH3 NH3 PbI3 nanowire photodetector.