title: Advanced Cd(II) complexes as high efficiency co-sensitizers for enhanced dye-sensitized solar cell performance.
abstract: This work reports on two new complexes with the general formula [Cd3(IBA)3(Cl)2(HCOO)(H2O)]n (1) and {[Cd1.5(IBA)3(H2O)6]·3.5H2O}n (2), which can be synthesized by the reaction of Cd(II) with rigid linear ligand 4-HIBA containing imidazolyl and carboxylate functional groups [4-HIBA = 4-(1H-imidazol-1-yl)benzoic acid]. Single-crystal X-ray diffraction analyses indicate that complex 1 is a 2D "wave-like" layer structure constructed from trinuclear units and complex 2 is just a mononuclear structure. Surprisingly, both complexes 1 and 2 appear as a 3D supramolecular network via intermolecular hydrogen bonding interactions. What's more, due to their strong UV-visible absorption, 1 and 2 can be employed as co-sensitizers in combination with N719 to enhance dye-sensitized solar cell (DSSC) performance. Both of them could overcome the deficiency of the ruthenium complex N719 absorption in the region of ultraviolet and blue-violet, and the charge collection efficiency is also improved when 1 and 2 are used as co-sensitizers, which are all in favor of enhancing the performance. The DSSC devices using co-sensitizers of 1/N719 and 2/N719 show an overall conversion efficiency of 8.27% and 7.73% with a short circuit current density of 17.48 mA cm(-2) and 17.39 mA cm(-2), and an open circuit voltage of 0.75 V and 0.74 V, respectively. The overall conversion efficiency is 27.23% and 18.92% higher than that of a device solely sensitized by N719 (6.50%). Consequently, the prepared complexes are high efficiency co-sensitizers for enhancing the performance of N719 sensitized solar cells.
authors.affiliation: Department of Chemistry, Harbin Institute of Technology, Harbin 150001, P. R. China. fanruiqing@hit.edu.cn ylyang@hit.edu.cn.
authors.forename: Song
authors.initials: S
authors.lastname: Gao
authors.forename: Rui Qing
authors.initials: RQ
authors.lastname: Fan
authors.forename: Xin Ming
authors.initials: XM
authors.lastname: Wang
authors.forename: Liang Sheng
authors.initials: LS
authors.lastname: Qiang
authors.forename: Li Guo
authors.initials: LG
authors.lastname: Wei
authors.forename: Ping
authors.initials: P
authors.lastname: Wang
authors.forename: Yu Lin
authors.initials: YL
authors.lastname: Yang
authors.forename: Yu Lei
authors.initials: YL
authors.lastname: Wang