Abstract
A composite photoanode comprising ultralong ZnO nanobelts and TiO2 nanoparticles was prepared and its performance in dye-sensitized solar cells (DSSCs) was optimized and compared to the photoanode consisting of conventional TiO2 nanoparticles. The ultralong ZnO nanobelts were synthesized in high yield by a facile solution approach at 90 oC followed by annealing at 500 oC. The effect of the ratio of ZnO nanobelts to TiO2 nanoparticles on the light scattering, specific surface area, and interface recombination were investigated. An optimum amount of ZnO nanobelts enhanced the photon-conversion efficiency by 61.4% compared to that of the conventional TiO2 nanoparticles. To further reduce the recombination rate and increase the carrier lifetime, Atomic Layer Deposition (ALD) technique was utilized to coat a continuous TiO2 film surrounding the ZnO nanobelts and TiO2 nanoparticles, functioning as a barrier-free access of all electrons to conductive electrodes. This ALD treatment improved the interface contact within the whole photoanode system, finally leading to significant enhancement (137%) in the conversion efficiency of DSSCs.
Highlights
Dye-sensitized solar cells (DSSCs) usually consist of a photoanode with a transparent TiO2 nanoparticle film sensitized with visible light harvesting dye, a redox electrolyte, and a platinum (Pt) counter electrode[1,2,3]
Taking advantage of high charge transfer efficiency of 1D ZnO nanostructures and large surface area of TiO2 nanoparticles, hybrid photoanodes consisting of their composites have been investigated and an enhancement of conversion efficiency was clearly demonstrated, while only 15–26.9% improvement was observed compared to conventional TiO2 nanoparticle films[15,16,17]
We systematically investigated the effect of the relative nanobelts/nanoparticles ratios on the performance of dye-sensitized solar cells (DSSCs), and a proposed mechanism was discussed in detail via current-voltage curves, incident photon-to-current conversion efficiency, reflectance and transmittance spectra, and electrochemical impendence spectroscopy measurements
Summary
Dye-sensitized solar cells (DSSCs) usually consist of a photoanode with a transparent TiO2 nanoparticle film sensitized with visible light harvesting dye, a redox electrolyte, and a platinum (Pt) counter electrode[1,2,3]. Nanoparticles provide large surface area for high amount of dye loading, the existence of numerous boundaries (Fig. 1(a)) in the nanoparticle films increases charge recombination occurred at the interfaces of TiO2 nanoparticles/dye/electrolyte. The main disadvantage of 1D or 2D nanostructures is their lower surface area (when compared with nanoparticle films) for insufficient adsorption of light-harvesting molecules, leading to relatively low conversion efficiency. Taking advantage of high charge transfer efficiency of 1D ZnO nanostructures and large surface area of TiO2 nanoparticles, hybrid photoanodes consisting of their composites have been investigated and an enhancement of conversion efficiency was clearly demonstrated, while only 15–26.9% improvement was observed compared to conventional TiO2 nanoparticle films[15,16,17]. We systematically investigated the effect of the relative nanobelts/nanoparticles ratios on the performance of DSSCs, and a proposed mechanism was discussed in detail via current-voltage curves, incident photon-to-current conversion efficiency, reflectance and transmittance spectra, and electrochemical impendence spectroscopy measurements
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
