Title:	Printed Tandem Solar Cell With Novel Semiconducting Material
Author(s):	B.T. Ko, Y.-C. Chen, C.-I. Yu, C.-P. Chen, S.H. Chan, Y.-H. Lin, Y.-D. Chen, C. Ting
Keywords:	Organic Solar Cell, Tandem, Devices
Topic:	Advanced Photovoltaics
Subtopic:	New Types of Cells and Modules
Event:	23rd European Photovoltaic Solar Energy Conference and Exhibition, 1-5 September 2008, Valencia, Spain
Session:	1CO.5.3
Pages:	229 - 234
ISBN:	3-936338-24-8
Paper DOI:	10.4229/23rdEUPVSEC2008-1CO.5.3
Price:	0,00 EUR
Document(s):	paper

Abstract/Summary:

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A novel soluble conjugated polymers, P2, with coplanar thiophene-phenylene-thiophene (TPT) unit are designed and synthesized as suitable active material used in tandem cells to compensate the poly(3-hexylthiophene) (P3HT)/[6,6]-phenyl-C71 butyric acid methyl ester (PC71BM) bulk-heterojunction (BHJ) cell in this paper. Full synthesis and characterization are included and discussed and direct comparisons are made with P3HT. P2 polymer bears advantages in both low optical bandgap (1.7 eV) and high hole mobility properties (3.4 x10-3 cm2/V-s from field effect transistor measurement). The former property shall ensure the photocurrent properties of a solar cell while the latter allows effective charge extraction and lower series resistance. Furthermore, the electrochemical studies of P2 indicate desirable HOMO/LUMO band structure that enables a high open-circuit voltage when pairing with PCBM acceptor. The best power conversion efficiency (PCE) of this polymer solar cell thus far based on P2/PC71BM system with a weight ratio of 1:3 reached 4.4% with a short circuit current density (Jsc) of 10.2 mA/cm2, an open circuit voltage (Voc) of 0.81 V, and a fill factor (FF) of 0.53 under AM 1.5G (100 mW/cm2). The preliminary data of the tandem cell with ITO glass/PEDOT:PSS/P2:PC71BM/TiOx/PEDOT:PSS/P3HT:PC71BM/TiOx/Al configuration has reached Jsc of 6.2 mA/cm2, Voc of 1.33 V, FF of 0.56 and an overall efficiency of 4.6 % under AM 1.5G (100 mW/cm2).