Introduction of Perylene Units for Enhanced Interchain Interaction in Conjugated Polymers for Organic Photovoltaic Devices

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• 作者：Ji-Hoon Kim ; Hee Un Kim ; Dongbo Mi ; Sung-Ho Jin ; Won Suk Shin ; Sung Cheol Yoon ; In-Nam Kang ; Do-Hoon Hwang
• 刊名：Macromolecules
• 出版年：2012
• 出版时间：March 13, 2012
• 年：2012
• 卷：45
• 期：5
• 页码：2367-2376
• 全文大小：569K
• 年卷期：v.45,no.5(March 13, 2012)
• ISSN：1520-5835

文摘

A series of semiconducting copolymers, poly[2,7-(9,9鈥?dioctylfluorene)-alt-5,5鈥?(4鈥?7鈥?di-2-thienyl-2鈥?1鈥?3鈥?benzothiadiazole)] (PFDTBT), poly[2,2鈥?(9,9-dioctyl-9H-fluorene-2,7-diyl)dithiophene-alt-5,5鈥?(4鈥?7鈥?di-2-thienyl-2鈥?1鈥?3鈥?benzothiadiazole)] (PFD2TBT), and their ter-polymers containing perylene units were synthesized using Suzuki coupling polymerization. The perylene units were introduced to improve the charge-transport ability by enhancing the 蟺鈥撓€ interaction between polymer chains. The resulting polymers were characterized by ¹H NMR, elemental analysis, DSC, and TGA. The synthesized polymers were soluble in common organic solvents, and formed smooth and uniform spin-coated thin films. All of the polymers studied were found to exhibit good thermal stability, losing less than 5% of their weight upon heating to approximately 350 掳C. Perylene- containing polymers showed higher field-effect mobilities than the corresponding PFDTBT or PFD2TBT polymers because of the enhanced 蟺鈥撓€ interaction between polymer chains upon the introduction of perylene units. Bulk heterojunction solar cells were fabricated with configuration of ITO/PEDOT:PSS/polymer:PC₇₁BM/TiO_x/Al. The devices using the perylene-containing polymers showed higher short-circuit currents, and fill factors than the corresponding PFDTBT or PFD2TBT devices. One of the fabricated devices using a perylene-containing copolymer showed a maximum power conversion efficiency of 3.16%, with a short circuit current density of 9.61 mA/cm², open circuit voltage of 0.81 V, and fill factor of 41%.