Enhancing mechanism of visible-light absorption for photovoltaic response and photoluminescence of Zn2SnO4 with high solubility of Bi3+

The enhanced visible-light absorption for photovoltaic response and room temperature photoluminescence of Bi3+-doped Zn2SnO4 nanoparticles are studied. The valence states of Bi3+ and Zn2+/Sn4+ are detected by their core level X-ray photoelectron spectra. BiZn+ and BiSn− from substitutions of Bi3+ for Zn2+/Sn4+ interattract and form noncompensated n-p codopant band to improve visible light absorption and facilitate electron transition for photovoltaic response and photoluminescence. Abundant surface states and weak built-in electric field near surface improve together the separation of photoinduced charges of n-type nanoparticle semiconductors. The investigation of high dopant solubility to enhance visible light absorption could be applied to other wide band gap ternary oxides.