title: Design of an organic redox mediator and optimization of an organic counter electrode for efficient transparent bifacial dye-sensitized solar cells.
abstract: A new thiolate/disulfide mediator was designed and synthesized by employing DFT calculations as a guide. It possesses high transparency to visible light, a very attractive feature for bifacially active transparent DSCs that require a highly transparent counter electrode (CE). Compared to the reported and most promising thiolate/disulfide mediator T(-)/T(2), this new analogous mediator produced a major enhancement in open circuit potential (V(OC)) by about 40 mV and correspondingly a higher power conversion efficiency (η) for DSCs. Furthermore, a highly uniform and transparent (transmittance > 91%) poly(3,4-ethylenedioxythiophene) (PEDOT(BE)) CE was prepared and could efficiently catalyze the reduction of the disulfide. Based on the novel transparent redox couple and PEDOT(BE) CE, a new type of iodine-free and Pt-free transparent bifacial DSC was successfully fabricated. This new bifacial device could not only yield a promising front-illuminated η of 6.07%, but also produce an attractive η as high as 4.35% for rear-side irradiation, which exceeds the rear-illuminated η of 3.93% achieved for the same type of device, employing the dark-colored I(-)/I(3)(-) electrolyte.
authors.affiliation: Michael Grätzel Center for Mesoscopic Solar Cells, Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, Hubei, PR China.
authors.forename: Xiong
authors.initials: X
authors.lastname: Li
authors.forename: Zhiliang
authors.initials: Z
authors.lastname: Ku
authors.forename: Yaoguang
authors.initials: Y
authors.lastname: Rong
authors.forename: Guanghui
authors.initials: G
authors.lastname: Liu
authors.forename: Linfeng
authors.initials: L
authors.lastname: Liu
authors.forename: Tongfa
authors.initials: T
authors.lastname: Liu
authors.forename: Min
authors.initials: M
authors.lastname: Hu
authors.forename: Ying
authors.initials: Y
authors.lastname: Yang
authors.forename: Heng
authors.initials: H
authors.lastname: Wang
authors.forename: Mi
authors.initials: M
authors.lastname: Xu
authors.forename: Peng
authors.initials: P
authors.lastname: Xiang
authors.forename: Hongwei
authors.initials: H
authors.lastname: Han