Anomalous pressure-responsive emission enhancement of FCO-CzS due to molecular configuration and electronic structure changes

[Display omitted] •A significant abnormal emission enhancement and blue shift of FCO-CZS are observed as pressure increases up to 20 GPa.•The molecular configuration and electronic structure changes under high pressure lead to abnormal pressure response emission.•It provides a new strategy for designing luminescent materials with ideal pressure response. Studying the stimuli-responsive properties of luminescent materials is important for their applications, while the luminescent materials studied up to now usually exhibit emission quenching and red shift in photoluminescence (PL) energy upon compression. Designing luminescent material with abnormal pressure responses remains challenging. Here, we report the discovery of abnormal luminescent properties of FCO-CzS upon compression. A theoretical study on the excited state decay process has been carried out for FCO-CzS at high pressure by hybrid quantum mechanics/molecular mechanics (QM/MM). A significant emission enhancement and blue shift are observed as pressure increases up to 20 GPa. This is opposite to the pressure response behaviours reported for other luminescent materials. It is further revealed that both the unique molecular configuration and the electronic structure change contribute to the anomalous pressure-responsive emission of FCO-CzS, which reduces the non-radiative rate and increases the radiative rate, respectively. Our study provides a strategy for the design of luminescent materials with desired pressure responses.