Novel Direct Nanopatterning Approach to Fabricate Periodically Nanostructured Perovskite for Optoelectronic Applications

Abstract

While indirectly patterned organic–inorganic hybrid perovskite nanostructures have been extensively studied for use in perovskite optoelectronic devices, it is still challenging to directly pattern perovskite thin films because perovskite is very sensitive to polar solvents and high‐temperature environments. Here, a simple and low‐cost approach is proposed to directly pattern perovskite solid‐state films into periodic nanostructures. The approach is basically perovskite recrystallization through phase transformation with the presence of a periodic mold on an as‐prepared solid‐state perovskite film. Interestingly, this study simultaneously achieves not only periodically patterned perovskite nanostructures but also better crystallized perovskites and improved optical properties, as compared to its thin film counterpart. The improved optical properties can be attributed to the light extraction and increased spontaneous emission rate of perovskite gratings. By fabricating light‐emitting diodes using the periodic perovskite nanostructure as the emission layers, approximately twofold higher radiance and lower threshold than the reference planar devices are achieved. This work opens up a new and simple way to fabricate highly crystalline and large‐area perovskite periodic nanostructures for low‐cost production of high‐performance optoelectronic devices.

Investigation of Carrier Dynamics in Templated Perovskite Films with Different Densities of Nanopores

“…Therefore, we believe that the fast PL decay lifetime¸1 is the result of competition between the interfacial quenching and two-carrier radiative recombination in the bulk of perovskite, resulting in the different trend from the steady-state PL measurement. It is noteworthy that the different trend between steadystate and time-resolved PL measurements has been recently reported by Mao et al 27 in a nanopatterned structure where radiative recombination dominantly occurs. Our results strongly suggest that a fast decay process should be further investigated to design perovskite devices with porous structures.…”

“…Note that our PS-based perovskite films do not physically float on the TiO 2 layer and the interface between perovskite and TiO 2 is continuous as shown in Figure S6. In addition to the decreased quenching, two-carrier radiative recombination could also be induced in the spatially confined regions between the PS nanopores, 27,28 which is also acceptable for the reasons for the enhancement of the PL peak intensities in the templated samples. The detailed discussion can be found in the following time-resolved measurement.…”

“…That is, radiative recombination occurs in proportion to n 2 , implying that radiative recombination is enhanced at high carrier density n such as nanopatterned structures and thin films. 27,28 In our templated samples, it is possible that radiative recombination could be induced by the high carrier density n within the spatially confined regions between the PS nanopores. In addition, the two-carrier radiative recombination in CH 3 NH 3 PbI 3 occurs at the timescale of 10 ns at sufficiently high excitation, 27,34 which is comparable to that of the interfacial quenching.…”

“…27,28 In our templated samples, it is possible that radiative recombination could be induced by the high carrier density n within the spatially confined regions between the PS nanopores. In addition, the two-carrier radiative recombination in CH 3 NH 3 PbI 3 occurs at the timescale of 10 ns at sufficiently high excitation, 27,34 which is comparable to that of the interfacial quenching. Therefore, we believe that the fast PL decay lifetime¸1 is the result of competition between the interfacial quenching and two-carrier radiative recombination in the bulk of perovskite, resulting in the different trend from the steady-state PL measurement.…”

1D Organic–Inorganic Hybrid Perovskite Micro/Nanocrystals: Fabrication, Assembly, and Optoelectronic Applications

“…), and an aligned architecture (horizontal/vertical, surface coverage, periodic structure, etc.). These different morphologies and architectures strikingly impact their optoelectronic properties, for example, carrier diffusion lengths, charge carrier mobilities, defect states, light path lengths, light extraction, etc . Therefore, it is critical to understand the underlying growth and assembly mechanisms of these methods and to achieve rational fabrication of 1D PMC arrays for device applications.…”