Low‐Threshold, External‐Cavity‐Free Flexible Perovskite Lasers

Abstract

A distinct advantage of halide perovskite semiconductors is their potential as gain media in high‐performance, all‐solution‐processed flexible lasers. However, most perovskite microlasers employ external optical resonators with rigid and high‐temperature/vaccum‐processed structures unsuitable for flexible applications. Here, low‐threshold, external‐cavity‐free perovskite lasers (≈550 nm, linewidth: ≈0.3 nm, quality factor: ≈1900, room temperature), prepared with excellent reproducibility using simple one‐step spin‐coating and low‐temperature annealing, are demonstrated. Exceptionally low lasing thresholds of 9.3 and 14.6 µJ cm−2 are achieved for external‐cavity‐free perovskite lasers on rigid and flexible substrates, respectively. The thresholds and quality factors are on par with that of high‐performance perovskite microlasers with well‐designed external cavities. The lasers exhibit good operational stability, showing half‐life of >1.8 × 108 pulses under optical pumping in air. Transient optical experiments reveal that the low thresholds stem from enhanced band‐to‐band spontaneous and stimulated emission processes in the high‐quality microcrystalline perovskite, effectively out‐pacing trap‐mediated and Auger processes detrimental to the lasing action. The flexible perovskite lasers retain >95% of the initial intensity after 10000 bending cycles, showing outstanding mechanical durability. As these lasers can be produced from solution within minutes at low costs, the findings are expected to enable high‐throughput, scalable fabrication of perovskite lasers for emerging applications.

Modulating the nonlinear optical properties of MAPbBr3 by metal ion doping

“…1 Various NLO materials, such as perovskites, 2–4 metal–organic frameworks, 5,6 metal oxides, 7,8 and two-dimensional materials, 9,10 have been explored for NLO devices. Among these, perovskites show the advantages of high light absorption, 11 extremely effective luminescence, 12 and prolonged carrier diffusion lengths, 13 making them ideal candidates for high performance optoelectronic devices, such as photodetectors, 14,15 lasers, 16,17 solar cells, 18,19 all-optical switches 20 and optical limiters. 21,22 Hybrid organic–inorganic metal halide perovskites, denoted as MAPbX 3 (MA = CH 3 NH 3 , X = Br, Cl, I), have demonstrated excellent NLO properties.…”

Improved Photoluminescence, Electroluminescence, and Laser Characteristics of 1-Naphthylmethylamine-Based Quasi-Two-Dimensional Perovskite Films at Lower Temperatures

“…Many optically pumped perovskite lasers have been reported to date. For example, Cao et al realized external-cavity-free perovskite lasers with low laser thresholds of ∼10 μJ cm –2 . Zhang et al showed that using hole transport layers (HTL) for perovskite lasers reduced the laser thresholds from 25.7 to 7.2 μJ cm –2 because of a hot-carrier cooling process being accelerated by extracting the holes in a perovskite by the HTL .…”

“…For example, Cao et al realized external-cavity-free perovskite lasers with low laser thresholds of ∼10 μJ cm −2 . 15 Zhang et al showed that using hole transport layers (HTL) for perovskite lasers reduced the laser thresholds from 25.7 to 7.2 μJ cm −2 because of a hot-carrier cooling process being accelerated by extracting the holes in a perovskite by the HTL. 16 Gao et al obtained room-temperature continuouswave (CW) lasing from quasi-two-dimensional (quasi-2D) perovskite films with a low threshold of 1.4 W cm −2 .…”

Recent advances in lead-free halide perovskites: from synthesis to applications

“…Lead-based halide perovskites are widely used in solar cells, [1][2][3][4][5][6] photodetectors, [7][8][9][10][11][12][13] lasers, [14][15][16] and other optoelectronic devices 17 due to their adjustable band gap, high absorption coefficient, and long carrier diffusion length. 18 Especially in the case of perovskite solar cells, their efficiency has improved from an initial 3.8% to 26.1% in fifteen years.…”