Organic-inorganic metal-halide perovskites possess excellent optoelectronic properties with applications toward high-efficiency solar cells and light-emitting diodes. Perovskites with high-mobility and long-lived photocarriers are ideal materials for photodetectors, whereas their relatively large dark currents restrict the signal-to-noise ratios of devices. 

Recently, Dr. Yuchen Wu and Prof. Lei Jiang's group at Technical Institute of Physics and Chemistry (TIPC), Prof. Hongbing Fu's group at Tianjin University and Prof. Xiang Zhang's group at University of California, Berkeley have realized the fabrication of high-quality two-dimensional perovskite nanowire arrays, which exhibit ultrasensitive photodetection. 

Through controlling the dewetting dynamics on the asymmetric-wettability topographical interface, the researchers have realized the controllable growth of single-crystalline 2D-perovskite nanowires. These nanowires are layer-by-layer self-organized into quantum wells with alternating conductive perovskite layers and insulating organic cations. The exposed layer edges on the surfaces of nanowires can efficiently dissociate excitons from crystalline interior into free carriers, which contribute to the high photoconductivity. Based on these single-crystalline nanowires, researchers have realized high responsivity exceeding 10⁴ A w^-1 and specific detectivity exceeding 7×10¹⁵ Jones, which represent the most sensitive perovskite photodetector to date.  

The study entitled “Single-crystalline layered metal-halide perovskite nanowires for ultrasensitive photodetectors” has been published in Nature Electronics. 

http://www.nature.com/articles/s41928-018-0101-5 

Fig. 4. Transient absorption for 2D-perovskite single-crystalline nanowire arrays.