Proceedings of International Conference on Hybrid and Organic Photovoltaics (HOPV18)
DOI: https://doi.org/10.29363/nanoge.hopv.2018.138
Publication date: 21st February 2018
Redox mediators in dye sensitized solar cells (DSCs) or hole transport materials (HTMs) in solid state DSCs (ssDSCs) play a major role determining the photocurrent and the photovoltage. The driving force for dye regeneration with the redox mediator should be sufficiently low to provide high photovoltages. With the introduction of new copper complexes as promising redox mediators or HTMs in DSCs both criteria are satisfied to enhance power conversion efficiencies and stability. The high photovoltages of over 1.0 V were achieved by the series of copper complex based redox mediators without compromising photocurrent densities. The solar-to-electrical power conversion efficiencies for [Cu(tmby)2]2+/1+, [Cu(dmby)2]2+/1+ and [Cu(dmp)2]2+/1+ based electrolytes were 10.3%, 10.0% and 10.3%, respectively, using the organic Y123 dye under AM1.5G illumination.1 Solar cells that operate efficiently under indoor lighting are of great practical interest as they can serve as electric power sources for portable electronics and devices for wireless sensor networks or the Internet of Things. Our photosystem combines two judiciously designed sensitizers, coded D35 and XY1, with the copper complex Cu(II/I)(tmby) as a redox shuttle (tmby, 4,4′,6,6′-tetramethyl-2,2′-bipyridine), and features a high open-circuit photovoltage of 1.1 V. The DSC achieves an external quantum efficiency for photocurrent generation that exceeds 90% across the whole visible domain from 400 to 650 nm, and achieves power outputs of 15.6 and 88.5 μW cm–2 at 200 and 1,000 lux, respectively, under illumination from a model Osram 930 warm-white fluorescent light tube. This translates into a PCE of 28.9%.2,3
1) Saygili, Y.; Söderberg, M.; Pellet, N.; Giordano, F.; Cao, Y.; Munoz-Garcia, A. B.; Zakeeruddin, S. M.; Vlachopoulos, N.; Pavone, M.; Boschloo, G.; Kavan, L.; Moser, J.-E.; Grätzel, M.; Hagfeldt, A.; Freitag, M. J. Am. Chem. Soc. 2016.
2) Freitag, M.; Daniel, Q.; Pazoki, M.; Sveinbjornsson, K.; Zhang, J.; Sun, L.; Hagfeldt, A.; Boschloo, G. Energy Environ. Sci., 2015, 8, 2634–2637.
3) Freitag, M.; Teuscher, D. J.; Saygili, Y.; Zhang, D. X.; Giordano, D. F.; Liska, D. P.; Hua, P. J.; Zakeeruddin, S. M.; Moser, J.-E.; Grätzel, M.; Hagfeldt, A. Dye-Sensitized Solar Cell for Efficient Power Generation under Ambient Lighting. Nature Photonics, 2017, 11, 372–378.