Controlling ZnO/poly(N-vinylcarbazole) hybrid morphology via surface modification of ZnO quantum dots for optoelectronic applications

Abstract

Hybrid organic-inorganic photovoltaic devices have not lived up to their potential because of poor interface properties. The work tries to improve charge transfer in the interface of organic-inorganic hybrid films of poly (N-vinylcarbazole) and ZnO quantum dots (QDs) via surface modification of ZnO and investigation of its effect on morphology of hybrid films. Two types of molecules having identical surface attachment and different terminated groups were used: 3-aminopropyltriethoxysilane (APTES) and phenyltriethoxysilane (PhTES). Hybrid film characteristics were investigated by use of UV absorption and photoluminescence spectral measurements and transmission electron microscopy. The results demonstrated that the both modifications, although different in effectiveness, enhanced polymer ordering and decreased phase separation problem of the hybrid films. Then, photovoltaic performance of modified and unmodified films was compared by measuring their photocurrent density-applied voltage (J-V ) curves. It was indicated that the photocurrent density increased in modified devices; however, they were performed differently so that the PhTES-modified device was revealed better than APTES-modified device. This work may provide a useful guideline to achieve low-cost hybrid UV switches or photodetectors.