Low-bandgap poly(4H-cyclopenta[def]phenanthrene) derivatives with 4,7-dithienyl-2,1,3-benzothiadiazole unit for photovoltaic cells

✍ Scribed by Jinwoo Kim; Sung Heum Park; Shinuk Cho; Youngeup Jin; Jaehong Kim; Il Kim; Jin Sook Lee; Joo Hyun Kim; Han Young Woo; Kwanghee Lee; Hongsuk Suh

• Book ID: 104088147
• Publisher: Elsevier Science
• Year: 2010
• Tongue: English
• Weight: 504 KB
• Volume: 51
• Category: Article
• ISSN: 0032-3861
• DOI: 10.1016/j.polymer.2009.12.009

✦ Synopsis

A series of conjugated polymer bearing 4H-cyclopenta[def]phenanthrene (CPP) unit have been synthesized and was evaluated in bulk heterojunction solar cell. The alternating copolymers with CPP unit were incorporated with 4,7-dithienyl-2,1,3-benzothiadiazole (DTBT) unit by Suzuki conditions. The newly synthesized copolymers, poly (2,6-((4,4-bis(2-ethylhexyl)

and poly(2,6-(4,4-bis(4-((2-ethylhexyl)oxy)phenyl)-4H-cyclopenta[def]phenanthrene)-alt-(4,7-((2-thienyl)-2,1,3-benzothiadiazole)))

(PBEHPCPP-DTBT), contain dialkyl and bis(alkoxyphenyl) groups in the CPP unit, respectively. The HOMO-LUMO energy bandgaps of these materials, estimated from UV-vis spectroscopy and cyclic voltammetry (CV), were 2.00 eV for PCPP-DTBT and 1.80 eV for PBEHPCPP-DTBT. Bulk heterojunction solar cells based on the blends of the polymers with [6,6]phenyl-C 71 -butyric acid methyl ester (PC 71 BM) gave power conversion efficiencies as 1.00% for PCPP-DTBT and 1.12% for PBEHPCPP-DTBT under AM 1.5, 100 mW/cm 2 .