Self-Powered CsPbBr3 Perovskite Nanonet Photodetector with a Hollow Vertical Structure

High-sensitivity self-powered photodetector based on an in-situ prepared CsPbBr3 microwire/InGaN heterojunction

Low-dimensional CsPbBr3 perovskite materials have gained widespread attention, derived from their remarkable properties and potential for numerous optoelectronic applications. Herein, the sample of CsPbBr3 microwires were prepared horizontally onto n-type InGaN film substrate using an in-plane solution growth method. The resulting CsPbBr3 microwire/InGaN heterojunction allows for the achievement of a highly sensitive and broadband photodetector. Particularly for the implementation in a self-supplying manner, the best-performing photodetector can achieve a superior On/Off ratio of 4.6×105, the largest responsivity ∼ 800.0 mA/W, a maximum detectivity surpassing 4.6× 1012 Jones, and a high external quantum efficiency approaching 86.5% upon 405 nm light illumination. A rapid response time (∼ 4.48 ms/7.68 ms) was also achieved. The as-designed CsPbBr3 microwire/InGaN heterojunction device without any encapsulation exhibits superior comprehensive stability. Besides, the device featuring as a single pixel imaging unit can readily detect simple images under broadband light illumination with a high spatial resolution, acknowledging its outstanding imaging capability. The robust photodetection properties could be derived from the intense absorption of CsPbBr3 MWs and high-efficiency charge carriers transporting toward the in-situ formed CsPbBr3/InGaN heterointerface. The results may offer an available strategy for the in-situ construction of best-performing low-dimensional perovskite heterojunction optoelectronic devices.

CsPbBr3-Based Nanostructures for Room-Temperature Sensing of Volatile Organic Compounds

All-inorganic halide perovskites, as a dominant member of the perovskite family, have been proven to be excellent semiconductors due to the great successes for solar cells, light-emitting diodes, photodetectors, and nanocrystal photocatalysts. Despite the remarkable advances in those fields, there are few research studies focusing on gas and humidity-sensing performances, especially for pure CsPbBr₃ and heterogeneous CsPbBr₃@MoS₂ composites. Here, we first report a valuable CsPbBr₃ sensor prepared by electrospinning, and the excellent gas sensing performances are investigated. The CsPbBr₃ sensor can quickly and effectively detect ethanolamine at room temperature. The response time is only 16 s, and the response to 100 ppm ethanolamine is as high as 29.87, besides the excellent repeatability and good stability. The theoretical detection limit is estimated to be 21 ppb. Furthermore, considering the irreplaceable role of heterostructures in regulating the electronic structure and supporting rich reaction boundaries, we also actively explored the EA sensitivity of inorganic CsPbBr₃-based heterogeneous composites CsPbBr₃@MoS₂. At the same time, the roles of the critical capping agents OA and OAm are systematically investigated. This work demonstrates the great potential of all-inorganic halide perovskites in promising volatile organic compound detection.

Ultrafast Speed, Dark Current Suppression, and Self-Powered Enhancement in TiO2-Based Ultraviolet Photodetectors by Organic Layers and Ag Nanowires Regulation

TiO₂-based photodetectors (PDs) have been hotspots in recent years for their excellent thermal stabilities and optoelectronic performance under ultraviolet (UV) light. However, the high dark current caused by defects in TiO₂ films has limited the detectivity (D) of these PDs. Here, the dark current of a TiO₂-based PD was effectively reduced by 3 magnitudes (from 0.1 mA to 20 nA) and D was increased to 1.2 × 10¹⁴ Jones by introducing PC71BM. The TiO₂/PC71BM heterojunction also made the PD self-powered, and by further introducing an interface layer of PEDOT:PSS and finely optimizing the electrode Ag nanowires (Ag NWs), the self-powered responsivity (R) was increased to 33 mA/W. Ultrafast rise/decay times (129 ns/1 ms at -1 V and 0.06 s/<1 μs at 0 V) were achieved. This work successfully applied an organic-inorganic heterojunction, an organic interface, and Ag NWs to suppress the dark current and enhance the self-powered photocurrent/R of inorganic PDs, providing a feasible strategy in high-performance UV PDs' design.