Pressure Induced Blue Shift Emission and Its Influence on the Band Gap in an Emerging 3D Semiconductor †

Abstract

Metal-organic chalcogenolate is one of excellent hybrid semiconductors, yet reports on their precise structures remain limited due to their large structural periodicity. Understanding the relationship between their structure and optical properties remained 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 ultra-violet excitation at atmospheric pressure. Notably this compound showed 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 contribute 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 suggested how the atomic contributions to the band structure. This work not only sheds light on the structural and optical responses to hydrostatic pressure but also explores their relationship in this 3D silver chalcogenolate, offering a new perspective on studying the nature of metal-organic frameworks semiconductors.