Year: 2025
Type: article
Abstract: High Resolution Image Download MS PowerPoint Slide Tin-halide perovskites currently offer the best photovoltaic performance of lead-free metal-halide semiconductors. However, their transport properties are mostly dominated by holes, owing to ubiquitous self-doping. Here we demonstrate a noncontact, optical spectroscopic method to determine the effective mass of the dominant hole species in FASnI 3, by investigating a series of thin films with hole densities finely tuned through either SnF 2 additive concentration or controlled exposure to air. We accurately determine the plasma frequency from mid-infrared reflectance spectra by modeling changes in the vibrational response of the FA cation as the plasma edge shifts through the molecular resonance. Our approach yields a hole effective mass of 0.28 m e for FASnI 3 and demonstrates parabolicity within ∼100 meV of the valence band edge. An absence of Fano contributions further highlights insignificant coupling between the hole plasma and FA cation. Overall, this approach enables noncontact screening of thin-film materials for optimized charge-carrier transport properties.
Source: ACS Energy Letters
Institutions: University of Oxford, University of Birmingham
Language: English
Subfield: Electrical and Electronic Engineering
Field: Engineering
Domain: Physical Sciences
Open Access status: hybrid
Estimated APC paid: $4,500
OpenAlex ID: W4413781175