Abstract: The present invention is a method for gettering undesirable atomic species from a vaporizing atmosphere during deposition of multi-element thin film phosphor compositions. The method comprises vaporizing one or more getter species immediately prior and/or simultaneously during the deposition of a phosphor film composition within a deposition chamber. The method improves the luminance and emission spectrum of phosphor materials used for full colour ac electroluminescent displays employing thick film dielectric layers with a high dielectric constant.