Water‐Stable 3D Cu 4 I 4 Framework With Near‐Unity Photoluminescence From Cluster‐Centered Self‐Trapped Excitons
Year: 2026
Type: article
Abstract: ABSTRACT Lead‐free alternatives to lead halide perovskites must achieve both high photoluminescence quantum yield (PLQY) and environmental stability for practical optoelectronic applications. While 0D copper halides demonstrate exceptional PLQY (>95%), their isolated clusters are vulnerable to moisture‐induced degradation. Conversely, 3D frameworks provide structural robustness but sacrifice luminescence efficiency. A water‐stable 3D Cu 4 I 4 single crystal framework (MpCuI) achieves 94% PLQY—the highest for 3D Cu 4 I 4 frameworks—through coordination‐driven assembly with 1‐methylpiperazine as a bifunctional N‐donor ligand. Cu─N coordination bonds (2.06–2.12 Å) extend Cu 4 I 4 cubane clusters into a close‐packed 3D network crystallizing in the highest‐symmetry orthorhombic space group ( Pnnn ) reported for this class. Spectroscopic and theoretical analyses reveal cluster‐centered self‐trapped exciton (CC‐STE) emission with strong exciton‐phonon coupling (Huang‐Rhys factor S = 22.54). MpCuI maintains 99.8% PLQY retention after 1‐week water immersion and demonstrates stable white‐light emission in proof‐of‐concept LED devices (CRI ∼84), establishing coordination bonding as a strategy for copper halide frameworks combining high efficiency with environmental robustness.
Source: Advanced Optical Materials
Language: English
Subfield: Electrical and Electronic Engineering
Field: Engineering
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W7134185106