Preparation and Characterization of Gd2O3: Er3+ Nanosphere Particles Combinated with Chitosan Gd2O3: Er3+@CS - Chau, Pham Thi Minh; Thai, Dang Van; Ha, Vu Thi Thai; Loc, Dinh Xuan; Nguyen, Tien Dai; Van, Bui Hong; Anh, Tran Kim (ECS journal of solid state science and technology, 2022)