Drastic transitions of excited state and coupling regime in all-inorganic perovskite microcavities characterized by exciton/plasmon hybrid natures

Abstract

Lead-halide perovskites are highly promising for various optoelectronic applications, including laser devices. However, fundamental photophysics explaining the coherent-light emission from this material system is so intricate and often the subject of debate. Here, we systematically investigate photoluminescence properties of all-inorganic perovskite microcavity at room temperature and discuss the excited state and the light–matter coupling regime depending on excitation density. Angle-resolved photoluminescence clearly exhibits that the microcavity system shows a transition from weak coupling regime to strong coupling regime, revealing the increase in correlated electron–hole pairs. With pumping fluence above the threshold, the photoluminescence signal shows a lasing behavior with bosonic condensation characteristics, accompanied by long-range phase coherence. The excitation density required for the lasing behavior, however, is found to exceed the Mott density, excluding the exciton as the excited state. These results demonstrate that the polaritonic Bardeen–Cooper–Schrieffer state originates the strong coupling formation and the lasing behavior.

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

“…Halide perovskite semiconductors are an emerging materials platform for a broad range of optoelectronic applications including photovoltaic solar cells, [ 1–7 ] light‐emitting diodes (LEDs), [ 8–17 ] and lasers. [ 18–25 ] As gain media for lasing, halide perovskites show exceptional potential for two main reasons: i) the broadly tunable emission of halide perovskites complements that of conventional III–V semiconductors lasers, for which efficiency deficit is more pronounced in the green region (the “green gap”); ii) the possibility for preparing all‐solution‐processed flexible lasers with performance comparable to or exceeding that of organic flexible lasers. [ 26–31 ] These may lead to new applications in wearable electronics, healthcare, and robotics.…”

Curved Photodetectors Based on Perovskite Microwire Arrays via In Situ Conformal Nanoimprinting

“…[5][6][7][8][9][10] In the medical field, the implantation of curved optoelectronic devices on complex surfaces of the skin or artificial organs is important for biological information compared with those of conventional materials. [37][38][39][40][41][42][43][44] For example, Zhang et al fabricated top-down etched microdisks and high-performance micro-lasers based on the CH 3 NH 3 PbBr 3 (MAPbBr 3 ) perovskite. [45] However, many technical challenges remain in fabricating perovskite-based micro/nano photodetectors (PDs) directly on curved substrates for curved-surface image sensors.…”

“…Perovskite materials play an important role in the development of micro/nanodevices because of their superior photoelectric properties compared with those of conventional materials. [ 37–44 ] For example, Zhang et al. fabricated top‐down etched microdisks and high‐performance micro‐lasers based on the CH 3 NH 3 PbBr 3 (MAPbBr 3 ) perovskite.…”

Competition of Carrier Kinetics Contributes to Amplified Spontaneous Emission in Quasi-2D/3D (PBA)2MAn–1PbnBr3n+1 Thin Films under Strip Light Mode

“…Recently, the amplified spontaneous emission (ASE) and/or lasing of quasi-2D perovskite thin films have been experimentally demonstrated. 8 For instance, Sargent and co-workers succeeded in fabricating the room-temperature single-mode deep-blue lasing of lowdimensional (BA) 2 Cs n−1 Pb n Cl 3n+1 perovskites with a low threshold of 6.5 μJ cm −2 . 9 Liang and co-workers obtained single-crystalline 2D perovskite random laser with a very narrow line width (∼0.1 nm) and a low threshold (∼0.5 μJ cm −2 ).…”

“…The variable n represents the number of inorganic [BX 6 ] 4– octahedral layers between the two layers of large organic cations. Recently, the amplified spontaneous emission (ASE) and/or lasing of quasi-2D perovskite thin films have been experimentally demonstrated . For instance, Sargent and co-workers succeeded in fabricating the room-temperature single-mode deep-blue lasing of low-dimensional (BA) 2 Cs n –1 Pb n Cl 3 n +1 perovskites with a low threshold of 6.5 μJ cm –2 .…”