Effect of PTB7 Properties on the Performance of PTB7:PC71BM Solar Cells

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• 作者：Chap Hang To ; Annie Ng ; Qi Dong ; Aleksandra B. Djuri拧i膰 ; Juan Antonio Zapien ; Wai Kin Chan ; Charles Surya
• 刊名：ACS Applied Materials & Interfaces
• 出版年：2015
• 出版时间：June 24, 2015
• 年：2015
• 卷：7
• 期：24
• 页码：13198-13207
• 全文大小：831K
• ISSN：1944-8252

文摘

The effect of poly[[4,8-bis[(2-ethylhexyl)oxy]benzo[1,2-b:4,5-b鈥瞉dithiophene-2,6-diyl][3-fluoro-2-[(2-ethylhexy)carbonyl]thieno[3,4-b]thiophenediyl]] (PTB7) properties on the optical properties, charge transport and photovoltaic performance of PTB7:[6,6]-phenyl C₇₁ butyric acid methyl ester (PC₇₁BM) blend films is investigated. We found that the variations in the molecular weight (M_w) and polydispersity index (PDI) of PTB7 mainly affect the phase separation and charge transport (hole mobility) in the blend films. The optical properties are also affected, but the increase in the extinction coefficient does not necessarily imply increased power conversion efficiency. The obtained power conversion efficiency for optimized thickness varied from 4.8% to 7.8% depending on the properties of PTB7. The wide range of obtained power conversion efficiencies illustrates the importance of optimizing the M_w and PDI to optimize bulk heterojunction morphology and achieve high performance solar cells.