Location and Number of Selenium Atoms in Two-Dimensional Conjugated Polymers Affect Their Band-Gap Energies and Photovoltaic Performance

详细信息    查看全文

• 作者：Jian-Ming Jiang ; Putikam Raghunath ; Hsi-Kuei Lin ; Yu-Che Lin ; M. C. Lin ; Kung-Hwa Wei
• 刊名：Macromolecules
• 出版年：2014
• 出版时间：October 28, 2014
• 年：2014
• 卷：47
• 期：20
• 页码：7070-7080
• 全文大小：608K
• ISSN：1520-5835

文摘

We synthesized and characterized a series of novel two-dimensional Se-atom-substituted donor (D)鈭捪€-acceptor (A) conjugated polymers鈥擯BDTTTBO, PBDTTTBS, PBDTTSBO, PBDTSTBO, PBDTTSBS, PBDTSTBS, PBDTSSBO, and PBDTSSBS鈥攆eaturing benzodithiophene (BDT) as the donor, thiophene (T) as the 蟺-bridge, and 2,1,3-benzooxadiazole (BO) as the acceptor with different number of Se atoms at different 蟺-conjugated locations, including the 蟺-bridge, side chain, and electron-withdrawing units. We then systematically investigated the effect of different locations and the number of Se atoms in these two-dimensional conjugated polymers on the structural, optical, and electronics such as band-gap energies of the resulting polymers, as determined through quantum-chemical calculations, UV鈥搗is absorption spectra, and grazing-incidence X-ray diffraction. We found that through the rational structural modification of the 2-D conjugated Se-substituted polymers the resulting PCEs could vary over 3-fold (from 2.4 to 7.6%), highlighting the importance of careful selection of appropriate chemical structures such as the location of Se atoms when designing efficient D鈭捪€-A polymers for use in solar cells. Among these tested BO-containing polymers, PBDTSTBO that has moderate band gaps and good open-circuit voltages (up to 0.86 V) when mixed with PC₇₁BM (1:2, w/w) provided the highest power conversion efficiency (7.6%) in a single-junction polymer solar cell, suggesting that these polymers have potential applicability as donor materials in the bulk heterojunction polymer solar cells.