Browsing by Author "Velusamy, Marappan"

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A ternary cascade structure enhances the efficiency of polymer solar cells
(2010)
Huang, Jen-Hsien
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Velusamy, Marappan
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Ho, Kuo-Chuan
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Lin, Jiann-Tsuen
;
Chu, Chih-Wei
In this study, a novel solution-processed small molecule (TQTFA) for use as an electron donor has been incorporated into organic solar cells based on poly(3-hexylthiophene) (P3HT) and (6,6)-phenyl C71-butyric acid methyl (PC[70]BM). The combination of TQTFA with P3HT and PC[70]BM allows not only a broad absorption but also tuning of the inter energy level leading to a higher short-circuit current (J(SC)) and open-circuit voltage (V(OC)). The best performing devices exhibited a power conversion efficiency of 4.50%. The efficiency is increased by almost 15% when compared to the one without TQTFA.
Dibenzo[f,h]thieno[3,4-b] quinoxaline-fullerene heterojunction bilayer solar cells with complementary spectrum coverage
(2010-10-01)
Kekuda, Dhananjaya
;
Huang, Jen-Shien
;
Velusamy, Marappan
;
Lin, Jiann T.
;
Chu, Chih-Wei
In the present article, potential of a bilayer organic solar cell has been investigated. We utilize newly synthesized small molecules, namely dibenzo[f,h]thieno[3,4-b]quinoxaline as electron donors for solar cells in heterojunction bilayer configuration. These small molecules with a narrow absorption band in the range 400-450 nm provide a complementary spectrum for the fullerene C(70), thereby leading to an overall power conversion efficiency of 2.6 +/- 0.2% under 100 mW/cm(2) incident radiation. Thermal annealing seems to impact the charge separation at the donor-acceptor interface, which eventually affects device performance. This work demonstrates that carefully optimized bilayer devices are comparable to the bulk heterojunction counterparts. (C) 2010 Elsevier B.V. All rights reserved.