Preferential Growth of Long ZnO Nanowire Array and Its Application in Dye-Sensitized Solar Cells

A liquid-phase chemical process for preferential growth of long ZnO nanowires has been developed. The process effectively suppresses homogeneous nucleation and prevents formation of ZnO particles in the bulk solution while allowing rapid growth of ZnO nanowires on seeded substrates. With this process, ZnO nanowires on seeded substrates can grow at an initial rate over 10 times faster than that in the previous process with bulk ZnO precipitation and nanowires of more than 30 mu m can be readily obtained within 10 h. The ultralong ZnO nanowires enable fabrication of dye-sensitized solar cells (DSCs) with up to 33 mu m thick sensitizing films (the thickest in the literatures) while maintaining high electron collection efficiency, which results in greatly improved performance compared to previously reported ZnO nanowire-based DSCs.