One-step Ar/O2 thermal plasma processing of Y2O3:Eu3+ red phosphors: Phase structure, photoluminescent properties, and the effects of Sc3+ codoping

► Thermal plasma processing yields Y2O3:Eu phosphors in one-step. ► The direct products are monoclinic and cubic phase mixtures. ► Sc3+ codoping effectively suppresses monoclinic crystallization. ► Better luminescence is achieved via Sc3+ codoping.