In the present work, we prepared two kinds of quantum sized ZnO particles whose size were 3 nm(P1) and 5 nm(P2), respectively, and studied their surface properties with surface photovoltage spectroscopy(SPS) and electric field induced surface photovoltage spectroscopy(EFISPS). The photovoltaic response of the two samples showed opposite dependence on external electric field. And when electric field was applied, the thresholds of photovoltaic response of the two samples were all red shifted. The results showed that the surface properties of P1 were different from those of P2, because of their different preparation process. We assigned that basic zinc acetate structure exist on the surface of P1 sample. While for P2 sample prepared by aging P1, that kind of surface structure disappeared, but the particles might be doped with lithium ions in the aging process.
The surface photovoltaic properties of four azo pigments(A, B, C, D) were studied by surface photovoltage spectra (SPS) and field induced surface photovoltage spectra (FISPS). The SPV responses of samples A and D were all enhanced when a negative electric field was applied and were all weaken when a positive voltage was applied. It shows that samples A and D indicate n type characteristics. On the contrary, samples B and C indicate p type characteristics. Combining with phase technique and molecular structure of azo pigments, the effect of group on Fermi energy level and conduction type of azo pigments was discussed.
The oligo phenylene vinylene(oligo PV)/SiO 2 composite film was prepared by the sol gel process. The surface photovoltage spectroscopy(SPS) and electric field induced surface photovoltage spectroscopy(EFISPS) had been used to investigate the charge transport process in olige PV/SiO 2 heterostructured composite. The results show that the oligo PV / SiO 2 composite film not only can improve the stability of oligo PV, but also have some photoelectric activity.
