Synthesis of poly(benzothiadiazole-co-dithienobenzodithiophenes) and effect of thiophene insertion for high-performance polymer solar cells.
We describe herein the synthesis of novel donor-acceptor conjugated polymers with dithienobenzodithiophenes (DTBDT) as the electron donor and 2,1,3-benzothiadiazole as the electron acceptor for high-performance organic photovoltaics (OPVs). We studied the effects of strategically inserting thiophene into the DTBDT as a substituent on the skeletal structure on the opto-electronic performances of fabricated devices. From UV/Vis absorption, electrochemical, and field-effect transistor analyses, we found that the thiophene-containing DTBDT derivative can substantially increase the orbital overlap area between adjacent conjugated chains and thus dramatically enhance charge-carrier mobility up to 0.55 cm(2)  V(-1)  s(-1). The outstanding charge-transport characteristics of this polymer allowed the realization of high-performance organic solar cells with a power conversion efficiency (PCE) of 5.1 %. Detailed studies on the morphological factors that enable the maximum PCE of the polymer solar cells are discussed along with a hole/electron mobility analysis based on the space-charge-limited current model.
School of Materials Science and Engineering Research Institute (ERI), Gyeongsang National University, Jinju 660-701 (Korea), Fax: (+82) 55-772-1659.
Hui-Jun
HJ
Yun
Yun-Ji
YJ
Lee
Seung-Jin
SJ
Yoo
Dae Sung
DS
Chung
Yun-Hi
YH
Kim
Soon-Ki
SK
Kwon
copolymerization; donor-acceptor systems; photovoltaic systems; semiconductors; thin films