Abstract
Terbium(III) doped indium hydroxide and Terbium(IV) doped indium oxide nanoparticles were synthesized by chemical compound precipitation. The size of 20nm and 30nm Tb(III) doped In(OH)3 nanoparticles were prepared by using deionized water(H-series) and diethylene glycol(D-series) as solvent respectively. The Tb(IV) doped In2O3 nanoparticles 7nm(H-series) and 9nm(D-series) in diameter were produced through oxygen annealing. The structural and optical properties were studied by changing the doping concentration of terbium ions. X-ray diffraction(XRD) reveals the body center cubic In(OH)3 and the bixbyite In2O3 structure. The size of nanoparticles were estimate by Scherrer equation. Transmission electron microscopy(TEM) imaged the morphology of sample HH5 and DH5 nanoparticles. It consisted with the size estimation result from XRD pattern. Compared with HH-series sampls, the DH has a broad luminescence band peak induce by oxygen vacancies in photoluminescence pattern. As the peak showed up the intensity of Tb 3+ intra-4f transition luminescence decreased. X-ray absorption near edge structure showed the change of Tb’s ion state form 3+ to 4+. That is the reason there is no luminescence in HO-series and DO-series samples. Extended x-ray absorption fine structure(EXAFS) measurements rule out the possibility of Tb forming oxide or cluster in the host and show Tb atoms are in the interstitial sites in In(OH)3 host and substitute In atoms in In2O3 host. The preparation in different solvent and adjusting the concentration of dopant is an indirect way to control oxygen vacancies. In DO-series samples there are oxygen vacancies around Tb ion. These defects would play a role as accepter to steal the electrons which were excited from Tb ions and recombine to luminesce. That is how the PL intensity of Tb in DH is weaker than in HH.