Efficient Amplified Spontaneous Emission from Solution-Processed CsPbBr₃ Nanocrystal Microcavities under Continuous Wave Excitation

Abstract

Solution-processed lasers are cost-effective, compatible with a vast range of photonic resonators, and suited for a mass production of flexible, lightweight, and disposable devices. The emerging class of lead halide perovskite nanocrystals (LHP NCs) can serve as a highly suitable active medium for such lasers, owing to their outstanding optical gain properties and the suppressed optical nonradiative recombination losses stemming from their defect-tolerant nature. In this work, CsPbBr 3 NCs are embedded within polymeric Bragg reflectors to produce fully solution-processed microcavities. By a systematic parametric optimization of the polymer mirrors, resonators with Q-factors up to 110 can be produced in the green, supporting amplified spontaneous emission (ASE) under continuous wave excitation, with a threshold as low as 140 mW/cm 2 . Angle-dependent reflectivity and luminescence studies performed below the ASE threshold demonstrate the strong spectral and angular redistribution of the CsPbBr 3 NC spontaneous emission when coupled to the cavity mode. Under resonance, amplification of the output intensity by a factor of 9 in the vicinity of the cavity mode and by a factor of 5 in the whole integrated emission along with an increase of the radiative rate accounted by a Purcell factor of 2 is obtained with respect to NCs deposited in reference microcavity structures.

Toward Continuous-Wave Pumped Metal Halide Perovskite Lasers: Strategies and Challenges

“…Copyright 2021 American Institute of Physics. (c) Reprinted with permission from ref . Copyright 2021 American Chemical Society.…”

All-Polymer Microcavities for the Fluorescence Radiative Rate Modification of a Diketopyrrolopyrrole Derivative

“…Some claims of Purcell effect observation were made for hybrid silica/polystyrene systems, 17 but possible extrinsic effects, such as changes in the refractive index of the effective medium, 18 and chemical effects, including exciton chemical traps, impurities, and local disorder affecting the structure, have been debated for these systems. 19 In general, photoluminescence (PL) lifetime (τ PL ) variations were reported for polymer synthetic opals 20 and 2D 21 and planar MCs, 22 but radiative rate variations were not investigated. Indeed, τ PL measurements alone cannot disentangle radiative (Γ R ) and nonradiative (Γ NR ) decay rates without information on the photoluminescence external quantum efficiency ( η , eq 1 ).…”

Flexible, Free-Standing Polymer Membranes Sensitized by CsPbX3 Nanocrystals as Gain Media for Low Threshold, Multicolor Light Amplification

“…A more viable, compact, and cost-effective path will be the implementation of quasi-continuous wave (cw) pulsed or pure cw lasers to initiate the lasing action from the NCs. Bulk and low dimensional perovskites have been recently demonstrated to sustain ASE or lasing even under cw-excitation in properly designed structures. ,,− However, these results are typically obtained at cryogenic temperatures, inaccessible by commercial Peltier-type cooling, or implement rigid cavities fabricated by rather elaborate epitaxial and lithographic techniques, that limit the practicality and compromise the cost-effectiveness and mass-production promise of a solution-based fabrication methodology. Finally, the great majority of the work involves the one specific popular emittergreen-luminescent CsPbBr 3 NCsallowing us to thoroughly study effective ligand and encapsulation strategies.…”