Conventional dye-sensitized solar cells have excellent charge collection efficiencies, high open-circuit voltages and good fill factors. However, dye-sensitized solar cells do not completely absorb all of the photons from the visible and near-infrared domain and consequently have lower short-circuit photocurrent densities than inorganic photovoltaic devices. Here, we present a new design where high-energy photons are absorbed by highly photoluminescent chromophores unattached to the titania and undergo Förster resonant energy transfer to the sensitizing dye. This novel architecture allows for broader spectral absorption, an increase in dye loading, and relaxes the design requirements for the sensitizing dye. We demonstrate a 26% increase in power conversion efficiency when using an energy relay dye (PTCDI) with an organic sensitizing dye (TT1). We estimate the average excitation transfer efficiency in this system to be at least 47%. This system offers a viable pathway to develop more efficient dye-sensitized solar cells.
Bibliographical noteKAUST Repository Item: Exported on 2020-10-01
Acknowledgements: The authors thank Y.C. Jun and M.L. Brongersma for access to time–resolved PL measurement equipment and assistance with measurements. B.E.H. would like to thank P. Péchy for his assistance in making the electrolyte. This work was supported by the King Abdullah University of Science and Technology Center for Advanced Molecular Photovoltaics and by the Office of Naval Research contract no. N00014-08-1-1163. B.E.H. received financial support from the National Department of Defense Science and Engineering Graduate Fellowship (NDSEG). E.T.H. is supported by the National Science Foundation GRFP and the Fannie and John Hertz Foundation. J.M.F. is supported by DOEBES contract DE-AC02-05CH11231. Financial support from ESF (SOHYDs), EU (ROBUST DSC, FP7-Energy-2007-1-RTD, 212792), MCyT (CTQ2008-00418/BQU, Consolider-Ingenio 2010 CSD2007-00010), MICINN (FOTOMOL, PSE-120000-2008-3) and CAM (MADRISOLAR, S-0505/PPQ/0225) are also gratefully acknowledged.
This publication acknowledges KAUST support, but has no KAUST affiliated authors.