標題: Carbazole-Based Ladder-Type Heptacylic Arene with Aliphatic Side Chains Leading to Enhanced Efficiency of Organic Photovoltaics
作者: Cheng, Yen-Ju
Wu, Jhong-Sian
Shih, Ping-I
Chang, Chih-Yu
Jwo, Pei-Chi
Kao, Wei-Shun
Hsu, Chain-Shu
應用化學系
Department of Applied Chemistry
關鍵字: Friedel-Crafts cyclization;carbazole;ladder-type;polymerization;organic photovoltaics
公開日期: 10-May-2011
摘要: By utilizing Friedel-Crafts cyclization, we have successfully designed and synthesized a ladder-type heptacyclic carbazole-dicyclopentathiophene (CDCT-C8) unit in which two outer thiophene subunits are covalently fastened to the central 2,7-carbazole core. The nitrogen-directing effect of the carbazole unit facilitates the intrarnolecular cydization and thereby suppresses the acid-induced dehydration, allowing us to incorporate two octyl side chains on the cyclopentadiene rings in good chemical yield. The distannyl-CDCT-C8 building block was copolymerized with benzothiadiazole (BT), dithienylbenzothiadiazole (DTBT), dithienyldiketopyrrolopyrrole (DTDPP) and quinoxaline (QX) units by Stile polymerization to afford four alternating donor acceptor copolymers, PCDCTBT-C8, PCDCTDTBT-C8, PCDCTDTDPP-C8 and PCDCTQX-C8, respectively. The device based on the PCDCTBT-C8:PG7IBM (1:3 in wt%) blend exhibited a V(oc) of 0.74 V, a J(sc) of 10.3 mA/cm(2), a FF of 60%, delivering an impressive PCE of 4.6%. This value represents one of the best performances among carbazole-based conjugated polymers in the literatures. The corresponding PCDCTBT-C8 :PC(71)BM blend showed a high hole mobility of 1.2 x 10(-3) cm(2) V(-1) s(-1), which is in good agreement with its high current density and fill factor. This improved performance is associated with the modification of the aliphatic side chains on the CDCT structure to optimize the interchain interactions for enhanced charge transporting. The devices based on PCDCTDTBT-C8, PCDCTDTDPP-C8 and PCDCTQX-C8 polymers also displayed promising efficiencies of 3.5%, 2.4%, and 1.8%, respectively.
URI: http://dx.doi.org/10.1021/cm200041v
http://hdl.handle.net/11536/8871
ISSN: 0897-4756
DOI: 10.1021/cm200041v
期刊: CHEMISTRY OF MATERIALS
Volume: 23
Issue: 9
起始頁: 2361
結束頁: 2369
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