Regulating the Auger Recombination Process in Two-Dimensional Sn-Based Halide Perovskites

Abstract

Two-dimensional tin iodide perovskite light-emitting diodes (LEDs) suffer from severe efficiency roll-off owing to the strong Auger recombination process. However, there has been controversy about the influence of defects and phonon scattering in regulating the Auger recombination process of Sn-based halide perovskites. In this study, we combine cation engineering, temperature-dependent transient absorption spectroscopy, and defect repair engineering to systematically investigate these effects on the Auger recombination rate of layered A2SnI4 (A = C6H5CH2CH2NH3 + (PEA+) and CH3(CH2)3NH3 + (BA+)) perovskites. The defect scattering and exciton–phonon scattering can reduce the exciton diffusion rate to influence the Auger recombination rate. Our study further reveals that defect scattering dominates in regulating the Auger recombination rate in two-dimensional Sn-based perovskites and is stronger than the exciton–phonon coupling effect. This work provides further insight into the inherent factors influencing the development of two-dimensional Sn-based halide perovskites in laser and LED technologies.

Dimensional Tailoring Endows Tin Halide Perovskite Solar Cells with High Efficiency and Stability

“…[56] Han et al pretreated the FASnI 3 perovskites with n-propylammonium iodide (PAI) before annealing, acting like a temple to guide the crystal growth of tin perovskites. [40] The PA + cations did not enter the FASnI 3 lattice and were just located at grain boundaries (Fig. 8a).…”

“…When n≥3, the perovskites have a great fit for sunlight-to-energy conversion. [39,40] Zhang et al revealed that defect scattering and exciton-phonon coupling effect caused reduced exciton diffusion rate, further reducing the collision probability between excitons and influencing the Auger recombination rate. [41] They induced excess BAI via cation stoichiometry regulation and successfully decreased the Auger recombination rate.…”

“…4 The molecular structures of bulky organic cations used in low-dimensional tin halide perovskites. [15,26,32,40,50,53,57,59,61,62,64,65,67,68,[70][71][72][73][74] with SnX 6 4− octahedrons tailoring with different n value. Dimensionality regulation not only enhances device stability and efficiency but also alleviates self-doping behavior and ion migration.…”

“…To obtain out-of-plane growth with high-oriented tin perovskite films, efforts by tuning the organic cations composition are paramount for optimizing charge transport. Meanwhile, the prepared low-dimensional films always present different n values, affecting their structural and photovoltaic properties in turn, which [40] Copyright 2020, Royal Society of Chemistry. (b) Schematic diagram of sequential deposition by surface treatment of 2D organic cations.…”

“…Fig.8(a) Diagram of templated growth of PPA-FASnI 3 perovskite films [40]. Copyright 2020, Royal Society of Chemistry.…”