Superior Phonon-Limited Exciton Mobility in Lead-Free Two-Dimensional Perovskites.
Nano Lett
; 24(12): 3638-3646, 2024 Mar 27.
Article
in En
| MEDLINE
| ID: mdl-38498912
ABSTRACT
Tin-based two-dimensional (2D) perovskites are emerging as lead-free alternatives in halide perovskite materials, yet their exciton dynamics and transport remain less understood due to defect scattering. Addressing this, we employed temperature-dependent transient photoluminescence (PL) microscopy to investigate intrinsic exciton transport in three structurally analogous Sn- and Pb-based 2D perovskites. Employing conjugated ligands, we synthesized high-quality crystals with enhanced phase stability at various temperatures. Our results revealed phonon-limited exciton transport in Sn perovskites, with diffusion constants increasing from 0.2 cm2 s-1 at room temperature to 0.6 cm2 s-1 at 40 K, and a narrowing PL line width. Notably, Sn-based perovskites exhibited greater exciton mobility than their Pb-based equivalents, which is attributed to lighter effective masses. Thermally activated optical phonon scattering was observed in Sn-based compounds but was absent in Pb-based materials. These findings, supported by molecular dynamics simulations, demonstrate that the phonon scattering mechanism in Sn-based halide perovskites can be distinct from their Pb counterparts.
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Language:
En
Journal:
Nano Lett
Year:
2024
Document type:
Article
Affiliation country:
United States
Country of publication:
United States