Enhanced cool white light emission in organic–inorganic metal halides through pressure-treated molecular configuration regulation

Abstract

Pressure-induced structural modulation can enhance photoluminescence (PL) emission in organic–inorganic metal halides (OIMHs). However, high-efficiency emission can hardly be retained after pressure treatment due to their reversible soft lattice characteristics and electronic structures. Herein, a significant PL enhancement of the organic cation [ETPP]⁺ in zero-dimensional (0D) OIMH (ETPP)₂ZrCl₆ is successfully achieved through high-pressure treatment. Notably, the emission intensity exhibits a remarkable 30-fold cool-white light enhancement upon the release of pressure. In situ infrared spectroscopy and theoretical calculations reveal that the enhanced π–π interactions are retained under ambient conditions after pressure release, which drives irreversible structural changes in [ETPP]⁺. More importantly, the pressure-enhanced C–H⋯Cl hydrogen bonds optimize the [ETPP]⁺ spatial arrangement within the rigid inorganic framework which suppresses non-radiative recombination through inhibited chemical bond vibrations and consequently achieves PL emission enhancement. This study demonstrates that pressure treatment effectively improves emission enhancement and enables the design of new OIMHs with the desired emission properties.