Ji Jingjing, Zhu Lei, Xiong Xia, Liu Feng, Liang Ziqi
Department of Materials Science, Fudan University, Shanghai, 200433, China.
School of Chemistry and Chemical Engineering, Frontiers Science Center for Transformative Molecules, In Situ Center for Physical Science and Center of Hydrogen Science, Shanghai Jiao Tong University, Shanghai, 200240, China.
Adv Sci (Weinh). 2022 Jul;9(21):e2200864. doi: 10.1002/advs.202200864. Epub 2022 May 20.
In all-polymer solar cells (all-PSCs), there remains such a dilemma that obtains good miscibility and crystallinity simultaneously. Herein a new family of Y-shape polymer acceptor, namely PYTT is developed, which is copolymerized from Y6 and benzotrithiophene units in three-way directions. Benefiting from its high-density end-chains and extended π-conjugation thanks to highly-branched 3D architecture, PYTT displays better organic solubility despite much higher molecular weights, larger crystallinity, and tighter π-stacking than the linear counterpart-PYT comprising Y6 and thiophene moieties, while showing identical optical absorption yet threefold higher photoluminescence intensity. In PYTT blend film with PM6 polymer donor, the interpenetrating nano-fibrillar structures are formed with well-intermixed polymeric domain sizes close to the exciton diffusion length, which is greatly conducive to exciton dissociation and charge transport in device. Consequently, PYTT-based all-PSCs exhibit all increased photovoltaic parameters, yielding a decent power conversion efficiency of 15.60%, which is ≈20% enhancement over PYT-based device, along with low nonradiative loss of 0.221 meV.
在全聚合物太阳能电池（全PSC）中，仍然存在一个两难困境，即如何同时获得良好的混溶性和结晶性。在此，开发了一种新型的Y形聚合物受体，即PYTT，它由Y6和苯并三噻吩单元在三个方向上共聚而成。得益于其高密度的端链以及由于高度分支的三维结构而扩展的π共轭，尽管分子量高得多，但PYTT显示出更好的有机溶解性，比由Y6和噻吩部分组成的线性对应物PYT具有更大的结晶性和更紧密的π堆积，同时显示出相同的光吸收但光致发光强度提高了三倍。在与PM6聚合物供体的PYTT共混膜中，形成了相互贯穿的纳米纤维结构，聚合物域尺寸良好混合，接近激子扩散长度，这极大地有利于器件中的激子解离和电荷传输。因此，基于PYTT的全PSC的所有光伏参数均有所提高，产生了15.60%的可观功率转换效率，比基于PYT的器件提高了约20%，同时非辐射损失低至0.221 meV。
