Electron Transporting Perylene Diimide-Based Random Terpolymers with Variable Co-Monomer Feed Ratio: A Route to All-Polymer-Based Photodiodes
Electron Transporting Perylene Diimide-Based Random Terpolymers with Variable Co-Monomer Feed Ratio: A Route to All-Polymer-Based Photodiodes
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DOI：
10.1021/acs.macromol.1c02159
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发表时间：
2022-01-03
期刊：
影响因子：
5.5
通讯作者：
Andreopoulou, Aikaterini K.
中科院分区：
文献类型：
--
作者：
Aivali, Stefania;Yuan, Peisen;Andreopoulou, Aikaterini K.
本文提出了一种基于随机供体-受体-供体-受体(D-A1)-(D-A2)分子构型的可加工n型三元聚合物的途径。咔唑作为给电子单元(D)，苝二酰亚胺（PDI）作为第一电子受体（A1），两种不同的苯并噻唑（BTZ）衍生物（二噻基取代-BTZ和二-3,4-乙烯二氧噻基取代-BTZ）中的任何一种作为第二电子接受单元（A2）。增加PDI共单体的含量，可以得到分子量更高、溶解度更高、n型性质更强的三元共聚物。随机PDICz-BTZ衍生物的物理化学性质根据共聚物的投料比进行微调。光电二极管器件的光活性层由富含PDI的三元聚合物组成，即P4具有75%的PDI含量，PCE10的电子供体，在不同的比例。对于一系列P4共混物，紫外可见光谱证实了共混膜在350-800 nm光谱区域的强吸收，AFM成像证实了它们的低表面粗糙度。通过电光器件性能的研究，确定了1:2的混合比例是获得最大电荷光电效率的最佳PCE10:P4组合。尽管n型P4三元聚合物的LUMO能量相对较深（E-LUMO = -4.04 eV），但发现陷阱诱导的电荷复合损失限制了PCE10:P4光电二极管的性能。p4单极器件的空穴和电子迁移率分别为2.2 × 10（-4）和6.3 × 10(-5) cm(2) v - 1s（-1）。
A route toward processable n-type terpolymers is presented herein based on the random donor-acceptor-donor-acceptor (D-A1)-(D-A2) molecular configuration. Carbazole is utilized as the electron donating unit (D) combined with perylene diimide (PDI) as the first electron acceptor (A1) and either one of two different benzothiadiazole (BTZ) derivatives ( di-thienyl substituted-BTZ and di-3,4-ethylenedioxythienyl substituted-BTZ) as the second electron accepting unit (A2). Increasing the content of the PDI co-monomer resulted in terpolymers of higher molecular weights, enhanced solubility, and stronger n-type character. The physicochemical properties of the random PDICz-BTZ derivatives are fine-tuned based on the feed ratio of the co-monomers. Photodiode devices were demonstrated, having photoactive layers composed of the rich in PDI terpolymer, namely, P4 having a 75% PDI content, and the PCE10 electron donor, under various ratios. For a range of P4 blend compositions, UV-Vis, is spectroscopy confirmed the strong absorption of the blend films across the 350-800 nm spectral region, and AFM imaging verified their low surface roughness. The study of the electro-optical device properties identified the 1:2 blending ratio as the optimum PCE10:P4 combination for maximum charge photogeneration efficiency. Despite the relatively deep LUMO energy of the n-type P4 terpolymer (E-LUMO = -4.04 eV), trap-induced charge recombination losses were found to limit the PCE10:P4 photodiode performance. Unipolar devices of the P4-alone exhibited hole and electron mobility values of 2.2 x 10(-4) and 6.3 x 10(-5) cm(2) V-1 s(-1), respectively.