Thermodynamic Barrier and Light Scattering Effects of Nanocube Assembled SrTiO3 in Enhancing the Photovoltaic Properties of Zinc Oxide Based Dye Sensitized Solar Cells

The light harvesting effects along with the energy barrier properties in dye sensitized solar cells (DSSCs) have been studied by utilizing an easily synthesizable and cost-effective nanocube assembled micron-sized SrTiO 3 (STO NCMS) in a binary hybrid photoanode with ZnO nanoparticles. An optimized photoanode loaded with 3% STO NCMS yielded a ∼2-fold increment in power conversion efficiency compared to pristine ZnO NP based device. Improved performance of photoanode with hybrid composite scaffold can be accredited to the boosted optical response in conjunction with impeded reverse tunneling probability of STO NCMS containing photoanode. Micron-sized STO NCMS provides a better light absorption in the photoanodes owing to optical confinement of incident light by multiple reflections generated from mirror-like facets of SrTiO 3 nanocubes as well as enhanced light scattering effects from individual entity. IPCE analysis revealed a better absorption of low energy photons that in turn resulted in enhanced solar to electricity generation for an optimized ratio of STO NCMS. An effective photoinduced charge separation has been achieved with a uniquely aligned band structure, resulting in enhanced power conversion efficiency. Electrochemical impedance analysis unveiled that incorporation of STO NCMS can effectively prolong the lifetime of photo-injected electrons (τ e ) as well as a higher value of recombination resistance ( R rec ) at the semiconductor/dye/electrolyte heterointerface indicating an impeded reverse tunneling probability of photoinjected electrons.