Abstract
Photoelectrochemical approach to solar energy conversion demands a kinetic optimization of various light-induced electron transfer processes. Of great importance are the redox mediator systems accomplishing the electron transfer processes at the semiconductor/electrolyte interface, therefore affecting profoundly the performance of various photoelectrochemical cells. Here, we develop a strategy—by addition of a small organic electron donor, tris(4-methoxyphenyl)amine, into state-of-art cobalt tris(bipyridine) redox electrolyte—to significantly improve the efficiency of dye-sensitized solar cells. The developed solar cells exhibit efficiency of 11.7 and 10.5%, at 0.46 and one-sun illumination, respectively, corresponding to a 26% efficiency improvement compared with the standard electrolyte. Preliminary stability tests showed the solar cell retained 90% of its initial efficiency after 250 h continuous one-sun light soaking. Detailed mechanistic studies reveal the crucial role of the electron transfer cascade processes within the new redox system.
Highlights
Photoelectrochemical approach to solar energy conversion demands a kinetic optimization of various light-induced electron transfer processes
The performance of cobalt redox mediators in Dye-sensitized solar cells (DSSCs) is still limited by rapid electron recombination to the electrolyte, which usually happens for one-electron redox mediators, and by slow dye regeneration and mass transport problems[10]
Feldt et al.[21] studied the regeneration and recombination kinetics in DSCs using a series of cobalt redox couples and suggested that a driving force of at least 0.4 eV is required in the dye regeneration process using a cobalt complex electrolyte
Summary
Photoelectrochemical approach to solar energy conversion demands a kinetic optimization of various light-induced electron transfer processes. The redox species, an essential component in DSSCs, affect significantly the charge transfer steps and markedly influence the performance of these devices In principle, they are required to ensure an efficient regeneration of oxidized dyes, diffuse rapidly in the electrolytic solution and possess fast charge transfer kinetics at the counter electrode. The challenge for further development of DSSCs relies strongly on the possibility of bringing the driving force for dye regeneration below 0.4 eV, while maintaining both fast regeneration and slow recombination One solution for this is to introduce an intermediate redox species, which has more positive redox potential than the cobalt complex species, but achieves faster regeneration. That study demonstrated that TPAA can regenerate the dye rapidly, inspiring us that it could be a potential alternative as co-mediator, helping to overcome constraints of cobalt-based electrolytes
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.
