Site‐Selective Transition‐Metal Doping Enables Enhanced Nonlinear Optical Absorption in Two‐Dimensional Lead‐Free Double Perovskites
Year: 2026
Type: article
Abstract: ABSTRACT Achieving high‐performance nonlinear optical (NLO) absorption in lead‐free perovskites remains a major challenge for advanced photonic applications. Here, we demonstrate that transition‐metal doping in two‐dimensional lead‐free double perovskite (BA) 4 AgBiBr 8 —where Fe and Cu selectively substitute Bi and Ag sites, respectively—serves as an effective strategy to boost NLO responses. Structural, spectroscopic, and theoretical analyses demonstrate the site‐selective doping behavior in (BA) 4 AgBiBr 8 and the introduction of distinct defect states within the bandgap, which provide abundant intermediate levels for excited‐state absorption under 800 nm femtosecond excitation. These defect‐mediated transitions significantly amplify the NLO response, yielding over a twofold increase in the nonlinear absorption coefficient and modulation depths of ∼70–75% at ultralow pulse energy (0.7 nJ). This study establishes site‐specific defect engineering as a general approach for designing high‐performance, environmentally benign NLO materials.
Source: Advanced Optical Materials
Language: English
Subfield: Electrical and Electronic Engineering
Field: Engineering
Domain: Physical Sciences
Open Access status: bronze
Funders: Natural Science Foundation of Shanghai, National Natural Science Foundation of China, Ministry of Education of the People's Republic of China, Shanghai Municipal Education Commission, State Administration of Foreign Experts Affairs, Higher Education Discipline Innovation Project, Australian Research Council, Fundamental Research Funds for the Central Universities
OpenAlex ID: W7129767454