Space‐Confined Synthesis of 2D All‐Inorganic CsPbI₃ Perovskite Nanosheets for Multiphoton‐Pumped Lasing

Abstract

With multiphoton‐pumped lasing, 2D all‐inorganic CsPbI3 perovskite nanoplates demonstrate a wide range of applications which results from its high crystalline quality and a nearly perfect naturally formed whispering gallery mode cavity. However, there still remains a difficulty in controllable synthesizing 2D CsPbI3 nanosheets with high crystalline quality. In this work, high‐quality 2D CsPbI3 perovskite nanosheets have been synthesized successfully with controllable morphology through space‐confined vapor‐phase epitaxial growth. More importantly, the morphology and crystalline quality of CsPbI3 perovskite nanosheets could be easily tuned by adjusting the diffusion and growth process achieved by adjusting the space‐confined distance and growth temperature. The typical square‐like CsPbI3 perovskite nanosheets can be as thin as 6.0 nm with a lateral size of 10.0 µm. The photoluminescence emission properties show a distinct dependence on thickness of these as‐grown CsPbI3 perovskite nanosheets. In addition, the as‐fabricated CsPbI3 perovskite nanosheets demonstrate one‐photon and two‐photon excitation‐pumped lasing with low‐threshold and high‐quality factor. The excellent multiphoton‐pumped lasing properties of the CsPbI3 perovskite nanosheets are attributed to their high crystalline quality, implying great promise for future applications in high‐performance optoelectronics.

Recent Progress in Metal Halide Perovskite Micro‐ and Nanolasers

“…Besides dependence on edge length, the thickness of microcavity also makes sense to the lasing thresholds . In the square‐like CsPbI 3 perovskite nanosheets, the PL spectra of the 2D CsPbI 3 with thicknesses of 3, 6, 12, 40, and 60 nm are shown in Figure a . The peak energy decreases obviously from 1.88 to 1.74 eV as the thickness increase from 3 to 60 nm (Figure b).…”

“…e) Numerically calculated effective refractive index ( n eff ) as a function of thickness t. f) Threshold intensity of plasmonic and photonic lasers versus perovskite thickness; the solid lines were used for Guidance. (a–c) Reproduced with permission . Copyright 2015, Wiley‐VCH.…”

Lead-Free Perovskites for Lighting and Lasing Applications: A Minireview

“…The main burst in this scientific area of utilizing the perovskite materials in lightning and lasing applications was caused by the synthesis of highly luminescent perovskite materials with QY above 80% [61,87]. At the present moment, the lasing perovskite materials possess wide range of morphology, including thin films [82,84,88,89,90,91,92], microstructures such as cubes [83,93,94,95,96,97], plates [81,98,99,100], wires [99,101,102,103,104], spheres [85,95,105], pyramids [97], nanosheets [106,107], microdisks [108,109], and quantum confined materials such as 2D R-P [110,111,112,113] and NCs [114,115,116,117], including NCs in glasses [118] and polymers [119]. Also, for the enhancement of the device performance, the perovskite materials can be patterned by ion beam lithography [109], laser ablation [108], or imprinting methods [89,120], and can be applied on the initially patterned substrates [81,90].…”

“…Also, for the enhancement of the device performance, the perovskite materials can be patterned by ion beam lithography [109], laser ablation [108], or imprinting methods [89,120], and can be applied on the initially patterned substrates [81,90]. Perovskite-based lasers usually are optically pumped, which can be also up-conversion excitation of PL [83,84,92,96,106,116,118]. By the type of pump source operation, one can consider pulsed [57,82,92,109,112,113] and continuous wave (CW) [89,102,119,121] light sources used.…”

Two‐Photon Up‐Conversion Photoluminescence Realized through Spatially Extended Gap States in Quasi‐2D Perovskite Films

“…Recently, amplified spontaneous emission (ASE) have been reported in 2D perovskites [(NMA) 2 (FA)Pb 2 Br 7 and (NMA) 2 (FA)Pb 2 Br 1 I 6 ] with stoichiometrically tunable wavelength from visible to near-infrared spectral range (530-810 nm) with the gain coefficient as high as > 300 cm −1 under pulse laser excitation. [22] In this work, we explore a new approach to realize multi-photon up-conversion photoluminescence (PL) in quasi-2D perovskite [(PEA) 2 (MA) 4 Pb 5 Br 16 (n = 5)] films by directly exciting broad gap states with continuous-wave (CW) infrared photoexcitation. [21] The discovery of edge states triggers a fundamental question of whether the gap states can be introduced as a new approach to develop multi-photon up-conversion light emission in solution-processing quasi-2D perovskite films.…”