The improvement of structure and photoluminescence properties of ZnAl2O4:Cr3+ ceramics synthesized by using solvothermal method

• Published in: Materials & design Vol. 115; pp. 37 - 45
• Main Authors: Zhang, D., Qiu, Y.H., Xie, Y.R., Zhou, X.C., Wang, Q.R., Shi, Q., Li, S.H., Wang, W.J.
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 05.02.2017
• Subjects: Aluminates; Ceramic; Ceramics; Ferromagnetism; Hydrothermal method; Lattices; Nanocrystals; Photoluminescence; Precursors; Spinel; Zinc aluminate; Ceramic; Zinc aluminate; Hydrothermal method; Photoluminescence
• ISSN: 0264-1275; 1873-4197
• DOI: 10.1016/j.matdes.2016.11.034

ZnAl2O4:Cr3+ nanocrystals were fabricated by using solvothermal method at various temperatures ranging from 160°C to 220°C. The influence of sodium acetate (NaAC) on the structural, photoluminescence and magnetic properties of Cr-doped zinc aluminate ceramics was investigated. The results showed that ZnAl2O4:Cr3+ polycrystals with sphere morphology (about 500nm) were formed without NaAC in precursors, while after adding NaAC into the precursors, octahedral and hexagonal single crystals of ZnAl2O4:Cr3+ were present. The PL spectra showed a series of sharp emission peaks ranging from 650nm to 730nm assigned to spin-forbidden 2Eg→4A2g transition of Cr3+ ions in spinel lattices corresponding to the result of EPR. Comparing to the PL spectra of ZnAl2O4:Cr3+ nanocrystals prepared by using sol-gel method, the intensity of R lines (originating from 2Eg→4A2g transition of Cr3+ ions in normal spinel lattices) was much larger than that of N lines (originating from 2Eg→4A2g transition of Cr3+ ions in inverse spinel lattices) for all samples. The EPR and VSM results showed that with grain size increasing, the interaction between Cr-Cr ions became weaker and the ferromagnetism of ZnAl2O4:Cr3+ nanocrystals was enhanced. [Display omitted] •The grain size of ZnAl2O4:Cr3+ crystals is enhanced by using sodium acetate.•The lower synthesized temperature can reduce the Al3+ in tetrahedral sites.•The fabricated ZnAl2O4:Cr3+ crystals have room-temperature ferromagnetism.