Monolithically grown CSPbBr3 by chemical vapor deposition for Self-Powered photodetector

What is it about?

The high-quality monolithic growth of perovskite films with larger grains on any substrate is a challenging task due to the instability of morphology, carrier mobility and chemical stability. In this work, we demonstrated the strategy to grow CsPbBr3 films with micron-sized grains along the (0 0 2) surface by chemical vapor deposition. The structural and optical characterizations have shown that the as-grown CsPbBr3 thin films are compact and packed without pin holes and have excellent optical quality for use in high-performance optoelectronic devices. The planar photodetector with the device configuration Ag/CsPbBr3/Ag shows a high photoresponsivity of 506.32 A/W and a specific detectivity of 8.29 × 1012 Jones at an incident light illumination of 22.3 µW/cm2. On the other hand, the vertically stacked device with ITO/SnO2/CsPbBr3/CuSCN/Ag configuration exhibits a photoresponsivity of 10.13 A/W at 0.05 V bias and 96 mA/W under 0 V bias. Specifically, the response time of the device in planar geometry is 241/205 ms, while the vertically stacked device has a response time of 20.51/21 ms at 0.05 V bias and 20.51/30 ms at 0 V bias. The results provide a new strategy for the growth of high-quality perovskite thin films and their effective application for high-performance optoelectronic devices.

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Why is it important?

The materials with the general formula ABX3 (where A is a cation, B is a metal, and X is a halide ion) are identified as promising candidates for optoelectronic devices due to their excellent optical and electrical properties. Specifically, all-inorganic perovskites such as CsPbX3 (X = Br, I, Cl) are emphasized for their superior stability compared to hybrid organic–inorganic counterparts. These perovskites are noted for their wide-ranging applications in solar cells, photodetectors, lasers, and LEDs, leveraging their high carrier mobility, long diffusion lengths, and extended carrier lifetimes. the importance of developing monolithic, compact perovskite films, which are characterized by large grains, pinhole-free surfaces, and smooth profiles. Such structures are crucial for integrating perovskite layers into devices like tandem solar cells to enhance performance. Different methods for growing high-quality perovskite films are mentioned, including solution processing, vacuum co-evaporation, and chemical vapor deposition (CVD). CVD is highlighted as particularly effective for producing large-area, defect-free, and compact films. The growth of CsPbX3 films using CVD is detailed, focusing on parameters like growth temperature, cooling rate, and carrier gas flow, which influence film morphology and structure. Examples include the growth of single-crystal CsPbBr3 epitaxial layers and other microstructures that enhance optoelectronic performance. he fabrication and testing of photodetectors using CsPbBr3 films. A planar photodetector with an Ag/CsPbBr3/Ag configuration demonstrated a high on/off ratio, while a vertically stacked device configuration (ITO/SnO2/CsPbBr3/CuSCN/Ag) showed even higher performance metrics, indicating potential for other optoelectronic applications. the challenges in growing monolithic CsPbBr3 films on glass substrates and suggests the need for precise optimization of growth parameters to achieve desired properties. The ongoing development of these materials suggests their potential applications beyond photodetectors, extending to LEDs and solar cells.These points collectively emphasize the growing importance of halide-based perovskites in optoelectronics, driven by advancements in material stability, fabrication techniques, and device integration capabilities.

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