Pressure dependent excited state dynamics behavior in CzCNDSB

Abstract High pressure can alter the properties of matter and modulate the excited-state relaxation behavior of materials without chemical intervention. In this study, high pressure was combined with steady-state absorption and fluorescence spectroscopy, as well as transient spectroscopy techniques, to investigate its effect on the optical properties of the stimuli-responsive material (2Z,2′Z)-2,2′-(1,4-phenylene)bis(3-(4-(9H-carbazol-9-yl)phenyl)acrylonitrile) (CzCNDSB). With increasing pressure, the steady-state absorption and fluorescence peaks of CzCNDSB crystals exhibit red shifts, which are fully reversible. At the same time, pressure causes the molecules to pack more closely, leading to an increase in both the number and energy of multiplet self-trapped state, while the energy of local excited state decreases. The steady-state and transient results provide information on electronic energy levels, excited-state dynamics, and other properties of CzCNDSB, which show strong pressure dependence. These findings highlight the potential of CzCNDSB for practical applications such as photodetectors and solar energy conversion.