Polyfluorene copolymer based bulk heterojunction solar cells

• Published in: Thin solid films 2004-02, Vol.449 (1), p.152-157
• Main Authors: Yohannes, Teketel, Zhang, F, Svensson, M, Hummelen, J.C, Andersson, M.R, Inganäs, O
• Format: Article
• Language: English
• Subjects: Applied sciences; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Electronic transport in condensed matter; Energy; Exact sciences and technology; Natural energy; Optoelectronic devices; Photoconduction and photovoltaic effects; Photoconduction and photovoltaic effects; photodielectric effects; Photoelectric conversion: solar cells and arrays; Photovoltaic conversion; Physics; Polymers; Semiconductors; Solar cells; Solar cells. Photoelectrochemical cells; Solar energy; TECHNOLOGY; TEKNIKVETENSKAP
• ISSN: 0040-6090; 1879-2731; 1879-2731
• DOI: 10.1016/S0040-6090(03)01348-8

Bulk heterojunction solar cells based on blends of photoactive layers of polyfluorene copolymer Poly((2,7-(9-(2′-ethylhexyl)-9-hexyl-fluorene)- alt-5,5-(4′,7′-di-2-thienyl-2′,1′,3′-benzothiadiazole))- co-(2,7-(9-(2′-ethylhexyl)-9-hexyl-fluorene)- alt-2,5- thiophene)) (LBPF3) acting as electron donor, and [6,6]-phenyl-C 61-butyric acid methylester (PCBM), acting as electron acceptor, were constructed and studied. The power conversion efficiency for a 1:4 (by weight) blend of LBPF3:PCBM under simulated solar light illumination having light intensity of 100 mW/cm 2 was 1.7%, and 9.2% under monochromatic (565 nm) light illumination with light intensity of 0.145 mW/cm 2. The maximum external quantum efficiency (incident photons to converted electrons) for this device was found to be above 40% from 400 to 560 nm. The effects of blend composition and film thickness on the photovoltaic parameters were also studied. The incident light intensity dependence of the short circuit current showed a linear relationship.