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Giant reduction of random lasing threshold in CH3NH3PbBr3 perovskite thin films by using patterned sapphire substrate


Hybrid organic–inorganic metal halide perovskites are currently arousing enthusiasm and stimulating huge activity across several fields of optoelectronics due to their outstanding properties. In this study, we present the incoherent random lasing (RL) emissions from CH3NH3PbBr3 perovskite thin films on both planar fluorine-doped tin oxide (FTO) substrates and patterned sapphire substrates (PSSs). A detailed examination of the spectral evolution indicates that inelastic exciton–exciton scattering called P-emission is the most plausible mechanism accounting for the lasing emissions. The RL threshold of the perovskite films on PSSs is found to be effectively reduced by more than one order of magnitude from 2.55 to 0.15 µJ/pulse compared to that on FTO substrates. The giant threshold reduction is ascribed to the enhanced random scattering of light and the photon recycling induced by the multireflection processes at the perovskite/PSS interface, which increases the likelihood that the inoperative random rays will reenter the possible optical loops formed among the perovskite particles, resulting in a considerable optical resonance enhancement. The simulation results reveal that the light extraction efficiency on the top facet of the perovskites is significantly increased by approximately 155% by utilizing the PSS instead of the FTO substrate. Moreover, the first direct experimental observation of the multireflection phenomenon of light, as well as the dynamic processes of photon propagation in the composite PSS structure are presented by Kerr-gate-based time-resolved photoluminescence. Our results provide an effective strategy to achieve high-performance perovskite random lasers and novel light-emitting devices for speckle-free full-field imaging and solid-state lighting applications, by introducing ingeniously-designed periodic nano/microscale optical structures.

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Publication details

The article was received on 27 Jan 2019, accepted on 11 Apr 2019 and first published on 11 Apr 2019

Article type: Paper
DOI: 10.1039/C9NR00863B
Citation: Nanoscale, 2019, Accepted Manuscript

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    Giant reduction of random lasing threshold in CH3NH3PbBr3 perovskite thin films by using patterned sapphire substrate

    G. Weng, J. Tian, S. Chen, J. Xue, J. Yan, X. Hu, S. Chen, Z. Zhu and J. Chu, Nanoscale, 2019, Accepted Manuscript , DOI: 10.1039/C9NR00863B

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