Multicolor luminescence properties of Ln7O6F9: RE3+ (Ln = Y, Lu; RE = Pr, Sm and Eu) nano-rods with bifurcation

• Published in: Journal of alloys and compounds 2017-01, Vol.692, p.471-477
• Main Authors: Xiang, Guang-Xin, Wang, Guo-Jun, Zhang, Zhi-Jun, Feng, He, Zhao, Jing-Tai, Wang, Jiao, Sun, Xin-Yuan, Mao, Ri-Hua, Wang, Yong
• Format: Article
• Language: English
• Subjects: Bifurcations; Charge transfer; Differential scanning calorimetry; Excitation; Fluorine; Fourier transforms; Gravimetry; Heat measurement; Heat treating; Heat treatment; Infrared radiation; Infrared spectroscopy; Ln(OH)1.69F1.31; Ln7O6F9; Luminescence; Luminescence properties; Nano-rod; Nanorods; Optical properties; Photoluminescence; Rare-earth; Trace elements
• ISSN: 0925-8388; 1873-4669
• DOI: 10.1016/j.jallcom.2016.08.306

The uniform 1D nano-rods of RE3+ doped Ln7O6F9 (Ln = Y and Lu; RE = Pr, Sm and Eu) were synthesized through a facile two-step hydrothermal method without extra fluorine source followed by post-heat treatment. The phase formation, morphologies, as well as photoluminescence properties of the materials were investigated. The precursor composition was determined to be Ln(OH)1.69F1.31 using the Fourier transform infrared spectrum (FT-IR), thermal gravimetric and differential scanning calorimetry (TG-DSC). The average lengths of Y7O6F9 and Lu7O6F9 were about 6.8 and 7.9 μm, respectively, with the average width of about 650 nm. It was interesting that the tip of the nano-rods exhibits a straight line and divergent umbrella shaped bifurcation for Y7O6F9 and Lu7O6F9, respectively. Upon ultraviolet excitation, Pr3+, Sm3+ and Eu3+ ions in Ln7O6F9 showed blue, orange and red emissions originating from their characteristic f-f transitions. In addition, the 4f15d1 → 4f2 band emissions (340–450 nm) as well as typical 4f2 → 4f2 line emissions (450–700 nm) of Pr3+ were observed in Pr3+-doped Ln7O6F9. For Sm3+-doped Ln7O6F9, only the typical f - f transitions of Sm3+ were observed with the absence of charge transfer (CT) band. However, the broad excitation bands at 255 nm attributing to the charge transfer transition of Eu3+ (i.e. O2− → Eu3+ CT) were observed in Eu3+-doped Ln7O6F9. [Display omitted] •RE3+-doped Ln7O6F9 nano-rods were obtained without extra fluorine source through a facile hydrothermal method.•The tip of the nano-rods exhibits varying degrees of bifurcation phenomena.•The charge transfer band (CTB) and f → d transition were observed in Eu3+ and Pr3+-doped Ln7O6F9, respectively.