Micro‐Nano Structure Functionalized Perovskite Optoelectronics: From Structure Functionalities to Device Applications

Abstract

Metal halide perovskite, an emerging photosensitive semiconductor, has been widely employed in solar cells, light‐emitting diodes, photodetectors, and lasers owing to its excellent photophysical properties and simple solution preparation processing. However, as a photoactive layer, the higher refractive index and thinner thickness of perovskite film can cause reflection and transmission at the interface, and confine the emitted light within devices, resulting in the poor incident photon absorption and emitted photon extraction. In addition, the intrinsic brittleness of perovskite material restricts its potential applications in flexible optoelectronics. Therefore, great effort has been put into micro‐nano structured perovskite optoelectronics, and the reported reviews mainly focus on the fabrication process of micro‐nano patterned perovskite. Herein, the functionalities of micro‐nano structures in optoelectronics, including improving the light trapping, light extraction, light modulation, carrier dynamics, mechanical robustness, and other novel functionalities, are comprehensively reviewed. The specific applications of these functionalities in perovskite‐based optoelectronic devices are then discussed in detail to provide a better understanding of the photophysical properties of micro‐nano structure functionalized optoelectronics. Finally, promising strategies to promote the multifunctional commercial applications of micro‐nano structured perovskite optoelectronics are provided.

Solution‐Processed Selective Area Homoepitaxial Growth of Suspended MAPbX3(X = Cl, Br) Perovskite Micro‐Arrays

“…Surface nano/microstructures engineering has shown its great power in the efficiency‐enhanced perovskite light‐harvesting [ 34–36 ] and light‐emitting devices. [ 37–42 ] However, most of the established perovskite micro/nanostructures are 2D periodic structures with a large mismatch and loss at the perovskite‐substrate interface as well as not well‐controlled orientation and morphology.…”

“…[ 37–42 ] However, most of the established perovskite micro/nanostructures are 2D periodic structures with a large mismatch and loss at the perovskite‐substrate interface as well as not well‐controlled orientation and morphology. [ 34,35,43,44 ] Compared to 2D periodic structures, 3D surface suspended nano/microstructures not only exhibit higher efficiency in extracting and directing light, which is expected to generate high‐yield light‐emitting diodes and low threshold laser arrays, but also can serve as elementary components for optical interconnections. [ 45,46 ] However, till to date, the fabrication of surface‐suspended nano/microstructures has not yet been reported for hybrid perovskites, possibly due to the serious structure degradation as exposed to polar solvents, high energy ions, and/or photons during the top‐down lithography proceedings.…”

A Polymer Strategy toward High‐Performance Multifunctional Perovskite Optoelectronics: From Polymer Matrix to Device Applications

“…[72][73][74] Encouragingly, the polymers that participated in the crystallization can regulate the dimension and size of perovskites, endowing novel optical properties. [75][76][77][78][79][80] The improved crystalline quality, fewer defect density, suppressed ion migration, and favorable carrier transportation will reduce the energy loss for high-performance perovskite optoelectronics. [81][82][83][84] The enhanced stability, reinforced mechanical robustness, selfhealing capacity, and novel optical properties will enrich the functions of multifunctional perovskite optoelectronics.…”

Honeycomb‐Type TiO2 Films Toward a High Tolerance to Optical Paths for Perovskite Solar Cells

“…In the latter case, TiO 2 is particularly designed to have a mesoporous structure for a large interfacial contact with perovskite to reduce electron diffusion lengths [9] . However, mesoporous TiO 2 films typically show a disordered spatial structure on a local scale, which have a limited role in light management [10] . Moreover, the mesopores with a small size pose a great challenge for a complete infiltration of perovskite solutions, particular for the case with a viscous solvent such as the ionic liquid methylammonium acetate (MAAc) used in the present work.…”

“…[9] However, mesoporous TiO 2 films typically show a disordered spatial structure on a local scale, which have a limited role in light management. [10] Moreover, the mesopores with a small size pose a great challenge for a complete infiltration of perovskite solutions, particular for the case with a viscous solvent such as the ionic liquid methylammonium acetate (MAAc) used in the present work. To address these issues, a rational design of TiO 2 structures is required.…”