Di Mario Lorenzo, Garcia Romero David, Pieters Meike J, Eller Fabian, Zhu Chenhui, Bongiovanni Giovanni, Herzig Eva M, Mura Andrea, Loi Maria A
Zernike Institute for Advanced Materials, University of Groningen Nijenborgh 4 Groningen 9747 AG The Netherlands
Dynamics and Structure Formation - Herzig Group, Institute of Physics, University of Bayreuth Universitätsstraße 30 Bayreuth 95447 Germany.
J Mater Chem A Mater. 2023 Jan 16;11(5):2419-2430. doi: 10.1039/d2ta08603d. eCollection 2023 Jan 31.
The development of an environmentally friendly fabrication process for non-fullerene acceptor organic solar cells is an essential condition for their commercialization. However, devices fabricated by processing the active layer with green solvents still struggle to reach, in terms of efficiency, the same performance as those fabricated with halogenated solvents. The reason behind this is the non-optimal nanostructure of the active layer obtained with green solvents. Additives in solution have been used to fine-tune the nanostructure and improve the performance of organic solar cells. Therefore, the identification of non-halogenated additives and the study of their effects on the device performance and stability are of primary importance. In this work, we propose the use of diphenyl ether (DPE) as additive, in combination with the non-halogenated solvent -xylene, to fabricate organic solar cells with a completely halogen-free process. Thanks to the addition of DPE, a best efficiency of 11.7% have been obtained for the system TPD-3F:IT-4F, an increase over 15% with respect to the efficiency of devices fabricated without additive. Remarkably, the stability under illumination of the solar cells is also improved when DPE is used. The addition of DPE has effects on the molecular organization in the active layer, with an enhancement in the donor polymer ordering, showing a higher domain purity. The resulting structure improves the charge carrier collection, leading to a superior short-circuit current and fill factor. Furthermore, a reduction of the non-radiative recombination losses and an improved exciton diffusion, are the results of the superior molecular ordering. With a comprehensive insight of the effects of DPE when used in combination with a non-halogenated solvent, our study provides an approach to make the fabrication of organic solar cell environmentally friendlier and more suitable for large scale production.
开发用于非富勒烯受体有机太阳能电池的环保制造工艺是其商业化的必要条件。然而，用绿色溶剂处理活性层制造的器件在效率方面仍难以达到与用卤化溶剂制造的器件相同的性能。其背后的原因是用绿色溶剂获得的活性层纳米结构不理想。溶液中的添加剂已被用于微调纳米结构并提高有机太阳能电池的性能。因此，识别非卤化添加剂并研究它们对器件性能和稳定性的影响至关重要。在这项工作中，我们提出使用二苯醚（DPE）作为添加剂，与非卤化溶剂二甲苯结合，以完全无卤的工艺制造有机太阳能电池。由于添加了DPE，TPD - 3F:IT - 4F体系获得了11.7%的最佳效率，相对于未添加添加剂制造的器件效率提高了15%以上。值得注意的是，当使用DPE时，太阳能电池在光照下的稳定性也得到了提高。DPE的添加对活性层中的分子组织有影响，供体聚合物有序性增强，显示出更高的畴纯度。由此产生的结构改善了电荷载流子的收集，导致优异的短路电流和填充因子。此外，非辐射复合损失的减少和激子扩散的改善是优异分子有序性的结果。通过全面了解DPE与非卤化溶剂结合使用时的效果，我们的研究提供了一种使有机太阳能电池制造更环保且更适合大规模生产的方法。
