It was noted that tin dioxide nanowires exhibited a strong visible

photoluminescence that was not observed in bulk crystalline SnO2. This was

usually attributed to oxygen vacancies, without specifying whether they were the

direct origin of the luminescence or whether their presence triggered other radiative

processes. An investigation was made here of the nature of the visible light

emission from SnO2 nanowires; showing that both experimental and theoretical ab

initio analyses supported the former hypothesis. On the basis of photoluminescence

quenching analysis and of first-principles calculations, it was shown that surface

bridging oxygen vacancies in SnO2 led to the formation of occupied and empty

surface bands whose transition energies were in strong agreement with

luminescence features and whose luminescence activity could be switched off by

the surface adsorption of oxidizing molecules.

Direct Role of Surface Oxygen Vacancies in Visible Light Emission of Tin Dioxide

Nanowires. S.Lettieri, M.Causà, A.Setaro, F.Trani, V.Barone, D.Ninno,

P.Maddalena: Journal of Chemical Physics, 2008, 129[24], 244710