Bimolecular and Auger Recombination in Phase-Stable Perovskite Thin Films from Cryogenic to Room Temperature and Their Effect on the Amplified Spontaneous Emission Threshold

Abstract

Recently, continuous-wave (CW) lasing was demonstrated at room temperature in quasi-2D perovskites. For 3D films, CW lasing at room temperature remains challenging. Issues hampering 3D materials include the temperature dependence of the (a) distribution of carrier energies, (b) buildup of photoinduced nonradiative channels, and (c) rates of bimolecular versus Auger recombination. We study the latter in a phase-stable 3D perovskite using high-index substrates to completely suppress amplified spontaneous emission (ASE). The bimolecular recombination coefficient decreases from 80 to 290 K (from (6.4 to 1.1) × 10 −10 cm −3 s −1 ), whereas the Auger coefficient stays constant at 3 × 10 −29 cm −6 s −1 . Above 250 K, the Auger rate exceeds the bimolecular rate at carrier densities corresponding to the ASE threshold. At lower temperatures, the decrease in the bimolecular rate coefficient with increasing temperature and the fraction of photoluminescence in the ASE band determine the temperature dependence of the ASE threshold.

Intense Electrical Pulsing of Perovskite Light Emitting Diodes under Cryogenic Conditions

“…Indeed, to date, continuous wave ASE in 3D perovskites was only shown at temperatures <160 K. [ 8,9,22 ] Furthermore, operation at cryogenic temperatures also exponentially lowers the ASE threshold. [ 4,8,18 ] Therefore, our results demonstrate that intense pulsing at cryogenic temperatures is a promising strategy for a proof‐of‐concept demonstration of an electrically pumped perovskite laser.…”

“…[13,14,16] Therefore, the reduction of the device operating temperature has been considered as one of the key strategies that likely must be applied in order to achieve electrically pumped perovskite lasing. [17] Moreover, cryogenic cooling of perovskite films and devices has also been shown to provide other benefits relevant for lasing, such as the exponential decrease in ASE threshold, [4,8,18] freezing of nonradiative recombination traps, higher device operational stability, etc. [19] Furthermore, considering that ion migration/distribution plays a crucial role in determining the optoelectronic characteristics of PeLEDs, [13,20,21] cryogenic cooling offers an opportunity to manipulate and freeze ion motions in the PeLED for an optimal device operation.…”

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

“…More complicated scenarios exist when we consider the non-negligible temperature variation or photoinduced defects. Although trap states are generally considered minor, a lot of defects will form after intense excitation due to the poor stability of perovskites, so trap filling is incomplete, accelerating trap-assisted nonradiative recombination. , Values for k 2 decrease monotonically with increasing temperature, but values for k 3 appear not to change much. , Moreover, recombination rate coefficients were found to be not invariant and dependent on excitation intensity. Values for k 2 increase with light intensity under the Mott density owing to Coulomb-enhancement effects, but decrease above the Mott density …”

“…(f) Effect of temperature on N A (black spheres) and the ASE threshold carrier density (red spheres). Reprinted with permission from ref . Copyright 2021 American Chemical Society.…”

“…However, the role of Auger recombination concerning CW lasing remains controversial in prior research. , Recently, Howard et al . studied bimolecular versus Auger recombination rate under different temperatures in a phase-stable bulk perovskite . At temperatures below 200 K, the rise in ASE threshold with temperature arises from the decrease in the bimolecular recombination rate caused by increased phonon scattering.…”