Tuning the optical, electronic and luminescence properties of LaOCl:Eu super(3+)viastructural and lattice strain modulation

• Published in: CrystEngComm Vol. 18; no. 6; pp. 907 - 916
• Main Authors: Lv, Li, Wang, Ting, Li, Sipeng, Su, Yiguo, Wang, Xiaojing
• Format: Journal Article
• Language: English
• Published: 01.02.2016
• Subjects: Band spectra; Band theory; Doping; Lattice strain; Luminescence; Modulation; Nanostructure; Optoelectronic devices
• ISSN: 1466-8033
• DOI: 10.1039/c5ce02098k

In this work, LaOCl:Eu super(3+) nanodisks have been successfully synthesized by a hydrothermal process followed by a subsequent heat treatment process. It is observed that the monotonous lattice contraction originating from the incorporation of Eu super(3+) into the LaOCl host matrix has a consequence on the structural variation and lattice strain modulation. Meanwhile, the lower Eu super(3+) doping content can induce the band gap narrowing of LaOCl, which is further confirmed by density functional theory (DFT) results. However, different to theoretical predictions, Eu super(3+) doped LaOCl nanodisks show a constantly narrowing band gap energy with increasing Eu super(3+) doping concentration as determined by UV-vis diffuse reflectance spectra, which is thought to be related to the increase in lattice strain. Futhermore, the Eu-O charge transfer band shifts to a low energy in the excitation spectra with increasing Eu super(3+) ion doping concentration, which can be attributed to the strengthening of the covalence of Eu-O bonds in the crystal structure environment of the LaOCl host matrix. For the Eu super(3+) doped LaOCl system, the luminescence intensity is influenced by the concentration quenching as well as the lattice strain. LaOCl:Eu super(3+) nanodisks exhibit good red emission properties with a maximum quantum efficiency of 87.4%. Thus, it is expected that the luminescence colors of Eu super(3+) doped LaOCl samples can be tuned by simply adjusting the relative doping concentration of Eu super(3+) ions, which might find potential applications in fields such as light display systems and optoelectronic devices.