A new approach for preparation of ternary bulk-heterojunction using dual-feed ultrasonic spray for organic solar cells
A new approach for preparation of ternary bulk-heterojunction using dual-feed ultrasonic spray for organic solar cells
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DOI：
10.1016/j.optmat.2019.03.020
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发表时间：
2019-05
影响因子：
3.9
通讯作者：
Swapnil R Tak;H. Tarkas;G. Bisen;Sanjay S. Ghosh;J. Sali
中科院分区：
文献类型：
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作者：
Swapnil R Tak;H. Tarkas;G. Bisen;Sanjay S. Ghosh;J. Sali
采用新型双馈入方法在超声喷雾中制备了以宽禁带聚合物P3HT和窄禁带聚合物PTB7为供体，ICBA为受体的三元体异质结。传统方法将两种给体聚合物在共同溶剂中紧密混合，形成BHJ中的两种给体聚合物的二元共混物，由于它们之间不利的相互作用，可能导致不利的相形态，并对BHJ中聚合物共混物的组成造成限制。不利的相互作用可能导致严重的分子紊乱，导致电荷重组陷阱位点，从而降低器件性能。本文提出的新方法避免了两个给体聚合物的密切混合，消除了对第二个给体在第一个给体中的分数的限制。此外，与传统方法相比，该方法还具有更好的聚合物有序性，从而显著提高了井眼迁移率。稳态光致发光研究表明，与单通道制备的P3HT:PTB7二元共混物相比，双通道方法制备的P3HT:PTB7二元共混物的FRET效率更高。利用该方法，即使第三组分浓度较高，也可以制备出具有最大功率吸收的三元BHJ，而不会影响其光电性能。虽然双进料法制备的BHJ的优越性能并没有体现在器件的功能上，但通过对供体和受体的更好选择，以及通过选择合适的溶剂对纳米级形貌的更多控制，器件的性能可能会提高到可接受的水平。本研究为三元有机太阳能电池的制备开辟了一条新的途径。
Ternary bulk heterojunctions using a wide band gap polymer P3HT and a narrow band gap polymer PTB7 as donors and ICBA as acceptor have been fabricated using a novel dual-feed approach in an ultrasonic spray. The binary blend of two donor polymers in a BHJ formed by a conventional method in which the two donor polymers are mixed intimately in a common solvent may lead to unfavourable phase morphology due to unfavourable interaction between them and puts constraints on the composition of the polymer blend in the BHJ. The unfavourable interaction may cause severe molecular disorder leading to charge recombination trap site, and thereby decreases the device performance. In the new method proposed in this paper intimate mixing of two donor polymers is avoided, which removes the constraint on the fraction of second donor in the first. Moreover, it also results in better polymer ordering leading to significantly higher hole mobility compared to that achieved with conventional method. The steady state photoluminescence study depicts more efficient FRET in P3HT:PTB7 binary blend prepared with dual channel method as compared to that prepared with single channel mode. With this method, ternary BHJ can be prepared even with higher concentration of the third component to have maximum power absorption, without compromising its optoelectronic properties. Although the superior properties of BHJ formed with the new dual-feed method did not reflected in similar performance in device functioning, with better choice of the donors and acceptor and with more control on nanoscale morphology through selection of proper solvents the device performance may improve to acceptable level. This report opens a new way of BHJ preparation in ternary organic solar cell fabrication.