Sequence Matters: Modulating Electronic and Optical Properties of Conjugated Oligomers via Tailored Sequence

详细信息    查看全文

• 作者：Benjamin N. Norris ; Shaopeng Zhang ; Casey M. Campbell ; Jeffrey T. Auletta ; Percy Calvo-Marzal ; Geoffrey R. Hutchison ; Tara Y. Meyer
• 刊名：Macromolecules
• 出版年：2013
• 出版时间：February 26, 2013
• 年：2013
• 卷：46
• 期：4
• 页码：1384-1392
• 全文大小：399K
• 年卷期：v.46,no.4(February 26, 2013)
• ISSN：1520-5835

文摘

Although sequence must necessarily affect the photophysical properties of oligomers and copolymers prepared from donor and acceptor monomers, little is known about this effect, as nearly all the donor/acceptor materials have an alternating structure. A series of sequenced p-phenylene鈥搗inylene (PV) oligomers was synthesized and investigated both experimentally and computationally. Using Horner鈥揥adsworth鈥揈mmons (HWE) chemistry, a series of dimers, trimers, tetramers, pentamers, and hexamers were prepared from two building block monomers, a relatively electron-poor unsubstituted p-phenylene鈥搗inylene (A) and an electron-rich dialkoxy-substituted p-phenylene鈥搗inylene (B). UV鈥搗is absorption/emission spectra and cyclic voltammetry demonstrated that the optoelectronic properties of these oligomers depended significantly on sequence. Calculations predicting the HOMO鈥揕UMO gap of the sequenced oligomers correlated well with the experimental properties for the 2- to 4-mers, and the consensus model developed was used to design hexameric sequences with targeted characteristics. Despite the weak acceptor qualities of the 鈥淎鈥?monomer employed in the study, HOMO鈥揕UMO gap differences of 0.25 eV were found for isomeric, sequenced oligomers. In no case did the alternating structure give the largest or smallest gap. The use of sequence as a strategy represents a new dimension in tailoring properties of 蟺-conjugated polymers.