Pressure-induced blue-shift emission and its influence on the band gap in an emerging 3D semiconductor†

Abstract

Metal–organic chalcogenolate is one of the excellent hybrid semiconductors; however, reports on their precise structures remain limited due to their large structural periodicity. Understanding the relationship between their structure and optical properties remains a significant challenge. External pressure is recognized as a clean and effective method for tuning the structure and properties of optical materials. In this study, we obtained a three-dimensional silver chalcogenolate, {Ag₁₀[(CH₃)₂CHS]₈(CN)₂}_n, which exhibited bright orange-red emission upon ultraviolet excitation at atmospheric pressure. Notably, this compound showed a unique piezoresponse to varying pressures. During compression, the emission centers experienced a blue shift of nearly 130 nm, followed by a red shift. Both mechanical stress and phase conversion contributed to this complex piezochromic behavior. In situ high-pressure X-ray diffraction measurements and Raman spectroscopy confirmed phase transitions during the color change. Density functional theory simulations further verified the direct band gap semiconductor characteristics of this compound and revealed how atomic contributions influenced the band structure. This work not only sheds light on the structural and optical responses to hydrostatic pressure but also explores their interrelationship in this 3D silver chalcogenolate, offering a new perspective on studying the nature of metal–organic framework semiconductors.