Electroluminesence (EL) thermal quenching refers a reduction in luminance, concomitant with a reduction in transferred charge, when an alternating-current thin-film electroluminescent (ACTFEL) device is operated at an elevated temperature. EL thermal quenching is found to be significant in SrS:Cu ACTFEL devices operated above ~60-80 °C. Maximum transferred charge-maximum applied voltage (Qmax-Vmax) and transferred charge capacitance (i.e., dQmax /dVmax vs Vmax) measurements as a function of temperature in conjunction with ACTFEL device simulation are employed in order to establish that EL thermal quenching arises from a thermally activated annihilation of positive space charge and a corresponding increase in the threshold voltage.
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