TiO2 coated ZnO nanorod to enhance efficiency of hybrid bulk heterojunction solar cells

The performance of organic-inorganic hybrid device based on poly(3-hexylthiophene) (P3HT) and vertically aligned ZnO nanorod depends upon the quality of the interface between organic and inorganic nanostructures. TiO₂ was used to improve the interface states between ZnO and P3HT. Vertically aligned ZnO nanorod was fabricated on top of the ITO glass by hydrothermal process. The nanorod has an average diameter of 80 nm and length of 600 nm as seen under scanning electron microscope (SEM). The transmittance window of this conductive nanorod layer fits perfectly with the absorption spectrum of organic polymer P3HT. Hybrid bulk heterojunction solar cell was fabricated by using P3HT as an electron donor and the vertical array of ordered ZnO nanorods as an electron acceptor. The P3HT - ZnO solar cell has the conversion efficiency of up to 0.48%. Interestingly solar cells fabricated using TiO₂ coated ZnO nanorod significantly increased the cell efficiency by 58%.