Epitaxial Growth of Large‐Scale Orthorhombic CsPbBr₃ Perovskite Thin Films with Anisotropic Photoresponse Property

Abstract

Inorganic cesium lead halide perovskite (CsPbX 3 , X = Cl, Br, I) is a promising material for developing novel electronic and optoelectronic devices. Despite the substantial progress that has been made in the development of large perovskite single crystals, the fabrication of highquality 2D perovskite single-crystal films, especially perovskite with a low symmetry, still remains a challenge. Herein, large-scale orthorhombic CsPbBr 3 single-crystal thin films on zinc-blende ZnSe crystals are synthesized via vapor-phase epitaxy. Structural characterizations reveal a "CsPbBr 3 (110)//ZnSe(100), CsPbBr 3 [−110]//ZnSe[001] and CsPbBr 3 [001]// ZnSe[010]" heteroepitaxial relationship between the covering CsPbBr 3 layer and the ZnSe growth substrate. It is exciting that the epitaxial film presents an in-plane anisotropic absorption property from 350 to 535 nm and polarization-dependent photoluminescence. Photodetectors based on the epitaxial film exhibit a high photoresponsivity of 200A W −1 , a large on/off current ratio exceeding 10 4 , a fast photoresponse time of about 20 ms, and good repeatability at room temperature. Importantly, a strong polarizationdependent photoresponse is also found on the device fabricated using the epitaxial CsPbBr 3 film, making the orthorhombic perovskite promising building blocks for optoelectronic devices featured with anisotropy.

Fast Crystallization-Deposition of Orderly Molecule Level Heterojunction Thin Films Showing Tunable Up-Conversion and Ultrahigh Photoelectric Response

“…This value is 2.7 times higher than those of carbon nitride nanotube membrane (5000), 32 and 3 orders of magnitude in comparison with the metal–organic framework (MOF) material in electrolyte. 33 Meanwhile, this value is also higher than those of inorganic perovskite 34 and organic single crystal-based 35 state-of-the-art optoelectronic devices. The better photogenerated charge separation efficiency of AD-TMA makes it a potential candidate for efficient photoswitches and photodetectors.…”

Recent Progress of Heterojunction Ultraviolet Photodetectors: Materials, Integrations, and Applications

“…These characteristics strongly recommend the organic–inorganic hybrid perovskites as ideal building blocks for high‐performance PDs. Perovskites with different structures (polycrystalline film,9 single crystal,10 and low‐dimensional nanostructure59)have been synthesized. Together with various device configurations, perovskites‐based devices demonstrate unprecedented progress in photodetecting performance 60.…”

“…Presently, the researches on perovskites,6–11 graphene,12 and other materials2,13–16 are emerging in an endless stream and these materials with excellent properties can be used for heterojunction UV PDs. Perovskites are a good choice for optoelectronic devices because of their tunable bandgaps, large extinction coefficient, and so on.…”

Enhanced Performance of Planar Perovskite Solar Cells Induced by Van Der Waals Epitaxial Growth of Mixed Perovskite Films on WS2 Flakes

“…used vapor‐phase epitaxy to prepare CsPbBr 3 single‐crystal thin films on zinc blende (ZnSe) crystals. [ 17 ] Benefiting from the good lattice match, orthorhombic CsPbBr 3 films with the (110) plane parallel to ZnSe (100) substrate were obtained. Shi and co‐workers reported high‐temperature vapor phase epitaxy growth of inorganic CsPbBr 3 and CsSnBr 3 perovskites on NaCl substrates under a controllable deposition rate.…”