Omnidirectional light-harvesting enhancement of dye-sensitized solar cells with ZnO nanorods

In this work, the chemical solution method was used to prepare one-dimensional (1-D) ZnO nanorod (NR) photoelectrodes, which were subsequently used in dye-sensitized solar cells (DSSCs). The effects of ZnO NRs on the omnidirectional light-harvesting performance of DSSCs were investigated by growing ZnO NRs with varying lengths as photoelectrodes. On the basis of field-emission scanning electron microscopy and ultraviolet (UV)-vis-near infrared (NIR) spectroscopy measurements on the ZnO NR photoelectrodes of varying lengths, it was observed that the dye adsorption and light-scattering properties of NRs are affected by their length. In addition, DSSCs were prepared using ZnO NRs of varying lengths. These DSSCs were examined via electrochemical impedance spectroscopy, monochromatic incident photon-to-electron conversion efficiency measurements, and solar simulations to measure their photovoltaic efficiencies, carrier lifetimes, and device characteristics in omnidirectional antireflection measurements. The highest photovoltaic efficiency between these DSSCs was 0.33%. Omnidirectional antireflection measurements were performed on DSSCs with different ZnO NR lengths, and it was observed that the smallest change in efficiency between angles of incidence of 0 degrees and 60 degrees was 23%. Therefore, the light-scattering properties of ZnO NR photoelectrodes improve the omnidirectional antireflection light capture characteristics of DSSCs.