Browsing by Author "Chiu, Chien-Lan"

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Design and characterization of highly efficient porphyrin sensitizers for green see-through dye-sensitized solar cells
(2009)
Lu, Hsueh-Pei
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Mai, Chi-Lun
;
Tsia, Chen-Yuan
;
Hsu, Shun-Ju
;
Hsieh, Chou-Pou
YD12 (eta = 6.7%) is a green sensitizer remarkable for its outstanding cell performance beyond that of N719 (eta = 6.1%) with no added scattering layer; the additional scattering layer assists N719 in promoting the efficiency in the red shoulder of the spectrum, but has only a small effect on the improvement of the cell performance for porphyrins.
Design and characterization of porphyrin sensitizers with a push-pull framework for highly efficient dye-sensitized solar cells
(2010)
Wu, Sung-Lin
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Lu, Hsueh-Pei
;
Yu, Han-Ting
;
Chuang, Shu-Han
;
Chiu, Chien-Lan
Novel porphyrin dyes YD14-YD17 with a push-pull framework were synthesized for dye-sensitized solar cells (DSSC); their spectral, electrochemical and photovoltaic properties were investigated. The absorption bands of these porphyrin dyes are broadened and red-shifted upon introduction of electron-donating groups (EDG) to the meso-positions via extension of p-conjugation. Electrochemical tests show that the first oxidation for these porphyrins occurs at a potential greater than that of the I(-)/I(3)(-) redox couple, and attachment of EDGs to the periphery of the porphyrin facilitates electron abstraction. The photovoltaic measurements show that YD14 and YD17 have a power conversion efficiency of similar to 7%. Introduction of EDGs to various meso-positions is demonstrated to be achievable, and porphyrin dyes with appropriate EDGs are promising candidates for highly efficient DSSCs.
Synthesis and characterization of diporphyrin sensitizers for dye-sensitized solar cells
(2010)
Mai, Chi-Lun
;
Huang, Wei-Kai
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Lu, Hsueh-Pei
;
Lee, Cheng-Wei
;
Chiu, Chien-Lan
Novel porphyrin dimers with broad and strong absorption in the visible and/or near IR regions have been synthesized; the meso-meso-linked porphyrin dimer (YDD1) exhibited the best photovoltaic performance with power conversion efficiency 5.2% under AM 1.5G one solar illumination.
Synthesis and characterization of porphyrin sensitizers with various electron-donating substituents for highly efficient dye-sensitized solar cells
(2010)
Hsieh, Chou-Pou
;
Lu, Hsueh-Pei
;
Chiu, Chien-Lan
;
Lee, Cheng-Wei
;
Chuang, Shu-Han
A series of porphyrin dyes with an electron-donating group (EDG) attached at a meso-position (YD1-YD8) have been designed and synthesized for use as sensitizers in dye-sensitized solar cells (DSSC). The nature of the EDG exerts a significant influence on the spectral, electrochemical and photovoltaic properties of these sensitizers. Absorption spectra of porphyrins having an amino group show broadened Soret band and red-shifted Q bands with respect to those of reference porphyrin YD0. This phenomenon is more pronounced for porphyrins YD7 and YD8 that have a pi-conjugated triphenylamine at the meso-position opposite the anchoring group. Upon introduction of an EDG at the meso-position, the potential for the first oxidation alters significantly to the negative whereas that for the first reduction changes inappreciably, indicating a decreased HOMO-LUMO gap. Results of density-functional theory (DFT) calculations support the spectroelectrochemical data for a delocalization of charge between the porphyrin ring and the amino group in the first oxidative state of diarylamino-substituted porphyrins YD1-YD4, which exhibit superior photovoltaic performance among all porphyrins under investigation. With long-chain alkyl groups on the diarylamino substituent, YD2 shows the best cell performance with J(SC) = 13.4 mA cm(-2), V(OC) = 0.71 V, and FF = 0.69, giving an overall efficiency 6.6% of power conversion under simulated one-sun AM1.5 illumination.