title: Enhanced Internal Quantum Efficiency in Dye-Sensitized Solar Cells: Effect of Long-Lived Charge-Separated State of Sensitizers.
abstract: Effective charge separation is one of the key determinants for the photovoltaic performance of the dye-sensitized solar cells (DSSCs). Herein, two charge-separated (CS) sensitizers, MTPA-Pyc and YD-Pyc, have been synthesized and applied in DSSCs to investigate the effect of the CS states of the sensitizers on the device's efficiency. The CS states with lifetimes of 64 and 177 ns for MTPA-Pyc and YD-Pyc, respectively, are formed via the photoinduced electron transfer (PET) from the 4-styryltriphenylamine (MTPA) or 4-styrylindoline (YD) donor to the pyrimidine cyanoacrylic acid (Pyc) acceptor. DSSCs based on MTPA-Pyc and YD-Pyc exhibit high internal quantum efficiency (IQE) values of over 80% from 400 to 600 nm. In comparison, the IQEs of the charge transfer (CT) sensitizer cells are 10-30% lower in the same wavelength range. The enhanced IQE values in the devices based on the CS sensitizers are ascribed to the higher electron injection efficiencies and slower charge recombination. The results demonstrate that taking advantage of the CS states in the sensitizers can be a promising strategy to improve the IQEs and further enhance the overall efficiencies of the DSSCs.
authors.affiliation: Collaborative Innovation Center of Chemical Science and Engineering , Tianjin, 300072, China.
authors.forename: Haiya
authors.initials: H
authors.lastname: Sun
authors.affiliation: Collaborative Innovation Center of Chemical Science and Engineering , Tianjin, 300072, China.|Tianjin Engineering Research Center of Functional Fine Chemicals , Tianjin, 300072, China.
authors.forename: Dongzhi
authors.initials: D
authors.lastname: Liu
authors.affiliation: Collaborative Innovation Center of Chemical Science and Engineering , Tianjin, 300072, China.|Department of Chemistry and Biochemistry and the Materials Technology Center, Southern Illinois University , Carbondale, Illinois 62901, United States.
authors.forename: Tianyang
authors.initials: T
authors.lastname: Wang
authors.affiliation: Collaborative Innovation Center of Chemical Science and Engineering , Tianjin, 300072, China.
authors.forename: Ting
authors.initials: T
authors.lastname: Lu
authors.affiliation: Collaborative Innovation Center of Chemical Science and Engineering , Tianjin, 300072, China.|Tianjin Engineering Research Center of Functional Fine Chemicals , Tianjin, 300072, China.
authors.forename: Wei
authors.initials: W
authors.lastname: Li
authors.affiliation: Collaborative Innovation Center of Chemical Science and Engineering , Tianjin, 300072, China.
authors.forename: Siyao
authors.initials: S
authors.lastname: Ren
authors.affiliation: Collaborative Innovation Center of Chemical Science and Engineering , Tianjin, 300072, China.
authors.forename: Wenping
authors.identifier: http://orcid.org/0000-0001-5686-2740
authors.initials: W
authors.lastname: Hu
authors.affiliation: Collaborative Innovation Center of Chemical Science and Engineering , Tianjin, 300072, China.|Department of Chemistry and Biochemistry and the Materials Technology Center, Southern Illinois University , Carbondale, Illinois 62901, United States.
authors.forename: Lichang
authors.initials: L
authors.lastname: Wang
authors.affiliation: Collaborative Innovation Center of Chemical Science and Engineering , Tianjin, 300072, China.|Tianjin Engineering Research Center of Functional Fine Chemicals , Tianjin, 300072, China.
authors.forename: Xueqin
authors.identifier: http://orcid.org/0000-0003-3135-4808
authors.initials: X
authors.lastname: Zhou
keywords: charge recombination; charge-separated (CS) sensitizers; electron injection; internal quantum efficiency (IQE); photoinduced electron transfer (PET)