Organic-inorganic lead halide perovskite microcrystal (MC) films are attractive candidates for fabricating high-performance large-area self-powered photodetectors (PDs) because of their lower trap state density and higher carrier mobility than their polycrystalline counterparts and more suitability of synthesizing large lateral area films than their single-crystal counterparts. Here, we report on the fabrication of self-powered all-inorganic CsPbBr perovskite MC PDs with high detectivity, using a modified solution synthesis method. The MCs are up to about 10 μm in size, and the MC layer is also about 11 μm in thickness. Under 473 nm laser (100 mW) illumination, the CsPbBr MC PDs show responsivity values of up to 0.172 A W, detectivity values of up to 4.8 × 10 Jones, on/off ratios of up to 1.3 × 10, and linear dynamic ranges of up to 113 dB. These performances are significantly better than those of PDs based on polycrystalline perovskite thin films and comparable with those of PDs based on perovskite single crystals.

All-inorganic halide perovskite is considered as outstanding candidate of organic-inorganic hybrid perovskite due to its superior stability. However, the low solubility of precursor and uncontrollable film growth result in poor film quality and impede the application of polycrystalline films greatly. In this work it is reported on a space-confined growth strategy to overcome the low solubility and fast crystal growth disadvantages via freezing the precursor solution within the gaps of ordered polystyrene sphere templates. Then, the dense CsPbBr 3 polycrystalline films realize low trap density (3.07 × 10 12 cm −3 ) and high carrier mobility (9.27 cm 2 V −1 s −1 ) after stoichiometric modulation. Photodetectors based on these films exhibit high performance in all figures of merit. Specifically, high responsivity up to 216 A W −1 and ultrashort response time (<5 µs) are achieved, which are better than those of all the CsPbBr 3 based PDs. A record detectivity of 7.55 × 10 13 and 3.1 × 10 5 Hz −3 dB bandwidth are also achieved. This work opens the window of high quality all-inorganic halide perovskite polycrystalline films and can be extended to rational application of more optoelectronic devices including solar cells, photoelectrodes, and ray detectors.

Perovskite photodetectors (PDs) with tunable detection wavelength have attracted extensive attention due to the potential application in the field of imaging, machine vision, and artificial intelligence. Most of the perovskite PDs focus on I‐ or Br‐based materials due to their easy preparation techniques. However, their main photodetection capacity is situated in the visible region because of their narrower bandgap. Cl‐based wide bandgap perovskites, such as CsPbCl3, are scarcely reported because of the bad film quality of the spin‐coated Cl‐based perovskite, due to the poor solubility of the precursor. Therefore, ultraviolet detection using high‐quality full inorganic perovskite films, especially with high thermal stability of materials and devices, is still a big challenge. In this work, high‐quality single crystal CsPbCl3 microplatelets (MPs) synthesized by a simple space‐confined growth method at low temperature for near‐ultraviolet (NUV) PDs are reported. The single CsPbCl3 MP PDs demonstrate a decent response to NUV light with a high on/off ratio of 5.6 × 103 and a responsivity of 0.45 A W−1 at 5 V. In addition, the dark current is as low as pA level, leading to detectivity up to 1011 Jones. Moreover, PDs possess good stability and repeatability.

Compared with a single nanowire (NW) or NW array, the simpler preparation process of an NW network (NWN) enables it to be fabricated in large-scale, flexible, and wearable applications of photodetectors (PDs). However, the NWN behaves many microinterfaces (MIs) between NWs, seriously limiting the device performance and stability. Here, we demonstrate a welding strategy for an MAPbI3 NWN, which enhances the crystallinity of the NWN and enhances the radial transmission of photogenerated carriers, leading to a better device performance with ultrahigh stability. Our NWN PDs fabricated by using the welding strategy showed ultrahigh performance with an on/off ratio and detectivity of 2.8 × 104 and 4.16 × 1012 Jones, respectively, which are the best performance for reported metal–semiconductor–metal (MSM) perovskite NWN PDs and are comparable to those of single-NW or NW array PDs. More importantly, our unpackaged NWN PDs show ultrahigh storage stability in air with a humidity of 55–65%, and the flexible NWN PDs can enable 250 bending cycles at different bending radii and 1000 bending cycles at fixed bending radii with no performance degradation being observed. These results indicate our welding strategy is very powerful for improving the performance of the NW device with applications in the wearable field.

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