We report a strong ac green electroluminescence (EL) in powder layers of terbium doped gadolinium oxysulfide (Gd2O2S:Tb) with methyl methacrylate as binder. An intensity of the order of 30 nits (Cd/m2) has been achieved. The EL emission spectra shows line emissions corresponding to5D3and5D4fluorescing levels of Tb3+ions. A very sharply risingB‐Vcurve normally related to insulator‐phosphor interface properties of a thin film electroluminescent device has been observed in these cells. This indicates the possibilities of barrier formation due to the localized space charge region in the absence of any prominent interfaces leading to impact excitation of Tb3+ions. This has further been confirmed by the excitation spectrum of Gd2O2S:Tb phosphor, which reveals Tb3+impurity absorption bands related to 4f8shell transitions.