Donor-Acceptor Sequence Engineering in pi-Conjugated Polymers for Enhanced Hole Transport and Photocurrent
Donor-Acceptor Sequence Engineering in pi-Conjugated Polymers for Enhanced Hole Transport and Photocurrent
复制标题
用于增强空穴传输和光电流的π共轭聚合物中的供体-受体序列工程
DOI：
10.1021/acs.jpcc.9b02866
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发表时间：
2019
影响因子：
3.7
通讯作者：
Shi Weidong
中科院分区：
文献类型：
--
作者：
Li Longhua;Ge Baoxin;Han Bolin;Shi Weidong
合成聚合物的序列依赖性是非常令人关注的。为了定制共聚物的电子和光学性质，非常希望实现定量的序列-性质关系。通过密度泛函理论（DFT）计算研究了给体（D）-受体（A）PTB 7共聚物的序列依赖的载流子输运和光学性质。采用高吞吐量方法构造了具有周期边界条件的字典序精确枚举结构。吸收系数，有效质量，变形势，空穴迁移率表现出强烈的响应序列模式。值得注意的是，bi/multiblock图案[DnAn]显示出比公知的[（DA）n]图案好得多的空穴迁移率和短路电流。例如，[DnAn]的空穴迁移率比[（DA）n]大12%-46%，并且[DnAn]的计算短路电流是[（DA）n]的1.5-2.5倍。我们的工作揭示了这种增强的原因：额外的D-D/A-A相互作用的本征带分裂可以诱导强的吸收系数和电子离域。另外的D-D/A-A组合的概念可以是普遍适用的，并且可以为具有可调性质的供体-受体聚合物的设计提供另外的自由度。
Sequence-dependent properties of synthetic polymers are of great concern. To customize the electronic and optical properties of copolymers, it is highly desirable to realize the quantitative sequence–property relationship. The sequence-dependent carrier transport and optical properties of the donor(D)–acceptor(A) PTB7 copolymer were studied through density functional theory (DFT) calculations. The exact enumeration structures in lexicographical order with periodic boundary conditions were constructed by a high-throughput approach. The absorption coefficient, effective mass, deformation potential, and hole mobility exhibit a strong response to the sequence patterns. Significantly, the bi/multiblock pattern [DnAn] shows much better hole mobility and short-circuit current than the well-known [(DA)n] pattern. For example, hole mobility of [DnAn] is 12%–46% larger than the [(DA)n, and the calculated short-circuit current of [DnAn] is 1.5–2.5 times that of [(DA)n]. Our work uncovered the reason for this enhancement: the intrinsic band splittings of the additional D–D/A–A interactions could induce strong absorption coefficient and electron delocalization. The concept of additional D–D/A–A combinations may be generally applicable and could provide an additional degree of freedom for the design of donor–acceptor polymers with tunable properties.