p–n junction induced electron injection type transparent photosensitive film of Cu₂O/carbon quantum dots/ZnO

An electron injection type transparent photosensitive Cu₂O/carbon quantum dot (C QD)/ZnO p−n junction film was prepared by a simple route in which, successively, the ZnO film was prepared by a sputtering process, the C QDs and Cu₂O were prepared by hydrothermal synthetic and chemical methods, then the C QDs and Cu₂O were introduced onto the surface of the ZnO film. The results indicated that the C QDs and Cu₂O were well combined with the ZnO film. The transparency and photosensitivity of this film were investigated, and exhibited an obvious photosensitive enhancement compared with those of the unmodified film. Through analysis, this enhancement of the photoconductivity could be attributed to the remarkable Cu₂O/ZnO p−n junction and C QDs with unique up-converted photoluminescence. (paper)