Browsing by Author "Cheng, Yi-Hui"

Now showing 1 - 1 of 1

Tuning Spectral and Electrochemical Properties of Porphyrin-Sensitized Solar Cells
(2010-07-15)
Lo, Chen-Fu
;
Hsu, Shun-Ju
;
Wang, Chin-Li
;
Cheng, Yi-Hui
;
Lu, Hsueh-Pei
Phenylethynyl-substituted porphyrin (PEI) sensitizers bearing a nitro, cyano, methoxy, or dimethylamino phenylethynyl substituent were prepared to examine the electron-donating or -withdrawing effects of dyes on the photovoltaic performance of the corresponding dye-sensitized solar cells. The overall efficiencies of power conversion of the devices show a systematic trend Me(2)N-PE1 > MeO-PE1 > CN-PE1 > NO(2)-PE1, for which Me(2)N-PE1 has a device performance about 90% of that of a N719-sensitized solar cell under the same experimental conditions. The superior performance of Me(2)N-PE1 is attributed to the effective electron-donating property of the dye that exhibits broadened and red-shifted spectral features. According to frontier orbitals based on DFT calculations, the electrons are effectively injected from the dye to TiO(2) for Me(2)N-PE1 and MeO-PE1 upon excitation, but that driving force reverses for NO(2)-PE1. Electrochemical tests indicate that both LUMO and HOMO levels show a systematic trend Me(2)N-PE1 > MeO-PE1 > CN-PE1 > NO(2)-PE1, consistent with the trend of variation of the short-circuit currents in this series of sensitizers.