Red photoluminescence mechanism in SnO 2 nanostructures

Tin dioxide nanoribbons were fabricated for clarifying the origin of the red photoluminescence band. It is found that the red band abruptly decreases its intensity after annealing the nanoribbons in O 2 . The time-resolved photoluminescence decay curve shows that the red band has a luminescence lifetime of ns. The electron spin resonance spectrum discloses that the red band is related to a kind of combined oxygen-vacancy ( V o + and V o ++ ) centers. Spectral analysis and theoretical calculation confirm that the red band arises from a transition between the combined oxygen-vacancy defect states in the band gap.