Browsing by Author "Zuo, Lijian"

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A Versatile Fluoro-Containing Low-Bandgap Polymer for Efficient Semitransparent and Tandem Polymer Solar Cells
(2013-10-01)
Chang, Chih-Yu
;
Zuo, Lijian
;
Yip, Hin-Lap
;
Li, Yongxi
;
Li, Chang-Zhi
The versatility of a fluoro-containing low band-gap polymer, poly[2,6-(4,4-bis(2-ethylhexyl)-4H-cyclopenta[2,1-b;3,4-b']dithiophene)-alt-4,7-(5-fluoro-2,1,3-benzothia-diazole)] (PCPDTFBT) in organic photovoltaics (OPVs) applications is demonstrated. High boiling point 1,3,5-trichlorobenzene (TCB) is used as a solvent to manipulate PCPDTFBT:[6,6]-phenyl-C-71-butyric acid methyl ester (PC71BM) active layer morphology to obtain high-performance single-junction devices. It promotes the crystallization of PCPDTFBT polymer, thus improving the charge-transport properties of the active layer. By combining the morphological manipulation with interfacial optimization and device engineering, the single-junction device exhibits both good air stability and high power-conversion efficiency (PCE, of 6.6%). This represents one of the highest PCE valuesfor cyclopenta[2,1-b;3,4-b']dithiophene (CPDT)-based OPVs. This polymer is also utilized for constructing semitransparent solar cells and double-junction tandem solar cells to demonstrate high PCEs of 5.0% and 8.2%, respectively.
Highly Efficient Polymer Tandem Cells and Semitransparent Cells for Solar Energy
(2014-05-01)
Chang, Chih-Yu
;
Zuo, Lijian
;
Yip, Hin-Lap
;
Li, Chang-Zhi
;
Li, Yongxi
Highly efficient tandem and semitransparent (ST) polymer solar cells utilizing the same donor polymer blended with [6,6]-phenyl-C-61-butyric acid methyl ester (PC61BM) and [6,6]-phenyl-C-71-butyric acid methyl ester (PC71BM) as active layers are demonstrated. A high power conversion efficiency (PCE) of 8.5% and a record high open-circuit voltage of 1.71 V are achieved for a tandem cell based on a medium bandgap polymer poly(indacenodithiophene-co-phananthrene-quinoxaline) (PIDT-phanQ). In addition, this approach can also be applied to a low bandgap polymer poly[2,6-(4,4-bis(2-ethylhexyl)-4H-cyclopenta[2,1-b;3,4-b\']dithiophene)-alt-4,7-(5-fluoro-2,1,3-benzothia-diazole)] (PCPDTFBT), and PCEs up to 7.9% are achieved. Due to the very thin total active layer thickness, a highly efficient ST tandem cell based on PIDT-phanQ exhibits a high PCE of 7.4%, which is the highest value reported to date for a ST solar cell. The ST device also possesses a desirable average visible transmittance (approximate to 40%) and an excellent color rendering index (approximate to 100), permitting its use in power-generating window applications.