Efficient Optical Amplification in the Nanosecond Regime from Formamidinium Lead Iodide Nanocrystals

Abstract

Lead halide perovskite nanocrystals (NCs) were recently found to exhibit extraordinary optical amplification properties. The great majority of such studies implemented ultrashort photon pulses in the femtosecond regime to initiate the stimulated emission process. Yet the realization of practical lasing applications based on such materials is crucially dependent on their ability to sustain optical amplification at significantly longer time scales, at which major losses associated with spontaneous emission and nonradiative recombination occur. Herein we demonstrate highly efficient amplified spontaneous emission (ASE) from close-packed films of formamidinium lead iodide perovskite (FAPbI3) NCs under excitation in the nanosecond regime. Systematic optimization of the NC processing and thermal treatment yields solids that exhibit high ASE net modal gain up to 604 cm–1 and weakly temperature sensitive ASE thresholds with room-temperature values as low as 140 μJ cm–2. The efficient optical amplification using excitation pulses comparable to the exciton lifetime combined with the excellent chemical durability and air stability of FAPbI3 NCs renders them outstanding gain media for continuous-wave lasers in the red and near-infrared.

Amplified Spontaneous Emission and Lasing in Lead Halide Perovskites: State of the Art and Perspectives

“…In a further experiment [33], FAPbI 3 and FA 0.1 Cs 0.9 PbI 3 NCs were synthesized, characterized by high PLQY and efficient ASE spanning the red and near infrared range. Efficient optical amplification in the nanosecond regime in FAPbI 3 NCs films was also demonstrated by Papagiorgis et al [34] that obtained room temperature ASE with a minimum threshold of 140 µJcm −2 in films annealed at 90 • , under 4 ns pumping at 532 nm, while no ASE was observed in as-deposited films. Further improvements of the NCs stability during purification were obtained by Krieg et al [35] that synthesized CsPbBr 3 NCs capped with zwitterionic long-chain molecules.…”

Robust Hydrophobic and Hydrophilic Polymer Fibers Sensitized by Inorganic and Hybrid Lead Halide Perovskite Nanocrystal Emitters

“…It is reasonable to assume that the NC agglomeration effects become increasingly pronounced as NC concentration increases. NC aggregation is consistent with the broadening and red-shift of the band-edge due to the loss of confinement and the decrease of the PL quantum yield and lifetime due to increased non-radiative recombination, as merging of the NCs is known to lead to exciton quenching effects (Stadler et al, 2015; Papagiorgis et al, 2018).…”

Environment-Induced Reversible Modulation of Optical and Electronic Properties of Lead Halide Perovskites and Possible Applications to Sensor Development: A Review

“…It has been demonstrated that metal-lead halide perovskites exhibit good light amplification emission. Evidence of high optical gains and efficient amplified spontaneous emissions (ASE) is reported for bulk polycrystalline thin films of organic- inorganic [ 29 , 31 , 109 , 110 ] and fully inorganic perovskites [ 33 , 35 ] and for perovskite nanocrystal films [ 16 , 38 , 111 , 112 , 113 , 114 ].…”