【作者】 赵林；

【导师】 谌烈； 吴飞燕；

【作者基本信息】 南昌大学 ， 化学， 2023， 硕士

【摘要】 半透明有机太阳能电池（Semitransparent organic solar cell,ST-OSCs）是有机太阳能电池（Organic solar cell,OSCs）的一个重要分支,它可以广泛应用于建筑物光伏建设、智能绿色大棚以及清洁能源汽车天窗等方面。为了早日实现ST-OSCs的商业化应用,研究者们在半透明有机光伏的研究上投入了大量的精力。但是,ST-OSCs仍然存在一个普遍的问题,即能量转化效率（Power Conversion Efficiency,PCE）和平均可见光透过率（Average visible transmittance,AVT）之间具有相互矛盾的内在关系。也就是说,提高其中的一个性能,往往会导致另一性能的下降。目前,如何调节好PCE和AVT的对立关系以获得更高的光利用率（Light utilized efficiency,LUE）已经成为当前的研究热点。在本文中,我们将致力于平衡PCE和AVT之间的相互内耗,从而实现更高的器件性能。在第一个工作中,为了缓解ST-OSCs中PCE和AVT相互对立的冲突关系,本论文构建了两个三元体系来探究其中的关系。第一个体系是以PM6:Y6（两者的质量比w:w=1:1.2）为主组分,以PCE10-2F作为第三组分,引入窄带隙（Narrow bandgap,NBG）给体的同时减少PM6在混合溶液中的比例,调控混合膜的吸收范围,增强光子捕获能力,提高激子传输效率和电荷传输效率。更进一步降低了混合膜在可见光区域的吸光强度,增强器件的透过率。最终,获得了13.38%的PCE和23.69%的AVT。第二个体系是以PCE10-2F:Y6（两者的质量比为w:w=1:2.5）为主组分,以PM6作为第三组分,适当引入宽带隙（Wide bandgap,WBG）给体增加了混合膜的吸光范围,提高了光子捕获能力,而且阶梯型的能级分布,降低了势能壁垒,更有利于激子跃迁,减少了电荷传输过程中产生的非辐射损失,有利于获得更高的开路电压(Open circuit voltage,V_OC)。此外,PM6与Y6具有较高的相容性,可以诱导混合膜形成更好的活性层形貌,获得分子堆砌紧密的微观结构。最终,我们实现了12.25%的PCE,36.57%的AVT以及4.48%的LUE。综上所述,在PM6:PCE10-2F:Y6体系中,当NBG给体PCE10-2F作为第三组分时,不仅有助于器件PCE的提升,而且还同时提升了AVT,这对ST-OSCs来说是一个全面的发展,有助于解决PCE和AVT之间的矛盾关系。在PCE10-2F:PM6:Y6体系中,随着PM6的添加,器件的PCE有所提升,虽然对AVT造成了一定程度的降低,LUE却是呈现出升高的趋势,这意味着,相对于AVT的略微降低,PCE的升高幅度更大,因此获得了更可观的器件性能。在第二个工作中,为了同时提升ST-OSCs的PCE和AVT,针对PCE10-2F:Y6体系,本论文提出了更加精细的研究方案。将长链聚合物的给体单元通过单边封端的方法调控成短链聚合物,也就是小分子化的概念,并且按照不同的比例添加到活性层中。一方面,小分子的引入有效降低了PCE10-2F的结晶性,有利于PCE10-2F:Y6活性层形成更合适的相分离尺寸,另一方面,基于相似相容的概念,低聚物的加入能够更好的改善器件的成膜形貌。此外,低聚物具有更低的最高占据分子轨道（High occupied molecular orbital,HOMO）能级,与PCE10-2F和Y6形成了阶梯型的能级分布,降低了势能壁垒,减少了激子传输过程中的非辐射损失,有利于提高二元器件的V_OC。同时,随着低聚物引入量的增加,混合溶液的浓度随之降低,活性层膜厚也会随着减小,从而增加了器件透过率。基于此,我们获得了11.71%的PCE,42.83%的AVT以及5.02%的LUE。也就是说,在二元体系中,我们通过聚合物小分子化的策略,不仅再一次突破了ST-OSCs的器件性能,并且更好的解决了ST-OSCs中AVT和PCE相互对立的内在矛盾,进一步促进了ST-OSCs的发展。更多还原

【Abstract】 Semitransparent organic solar cells（ST-OSCs）are an important branch of organic solar cells（OSCs）,which can be widely used in building photovoltaic construction,intelligent green greenhouses,and clean energy car skylights.In order to achieve the commercial application of ST-OSCs as soon as possible,researchers have invested a lot of energy in the research of semitransparent organic photovoltaics.However,there is still a common problem with ST-OSCs,where there is an inherent contradiction between the power conversion efficiency（PCE）and the average average visible transmittance（AVT）.Improving one performance will inevitably lead to a decrease in the other.At present,how to adjust the opposition between PCE and AVT to achieve higher light utilization efficiency（LUE）has become a current research hotspot.In this article,we will strive to balance the mutual internal friction between PCE and AVT,in order to achieve higher device performance.In the first work,in order to alleviate the conflicting relationship between PCE and AVT in ST-OSCs,we constructed two ternary systems to explore their relationships.The first system consists of PM6:Y6（mass ratio w:w=1:1.2）as the main component,and PCE10-2F as the third component.By introducing narrow bandgap（NBG）donors while reducing the proportion of PM6 in the mixed solution,the absorption range of the mixed film can be adjusted,the photon capture ability can be enhanced,and the exciton and charge transfer efficiency can be improved.Furthermore,it reduces the absorption intensity of the mixed film in the visible light region and enhances the transmittance of the device.In this system,we obtained13.38%PCE,23.69%AVT,and 3.17%LUE.The second system is composed of PCE10-2F:Y6（with a mass ratio of w:w=1:2.5）as the main component and PM6 as the third component.The appropriate introduction of wide bandgap（WBG）donors increases the absorption range of the hybrid film,improves photon capture ability,and the stepped energy level distribution reduces the potential energy barrier,which is more conducive to exciton transitions,reduces non-radiative losses generated during charge transfer,and is conducive to obtaining higher open circuit voltage(V_OC).In addition,PM6 and Y6 have high compatibility,which can induce the formation of a better morphology of the active layer in the mixed film and obtain a microstructure with tightly packed molecules.In the end,we achieved 12.25%PCE,36.57%AVT,and 4.48%LUE.All in all,in the PM6:PCE10-2F:Y6 system,when the NBG donor PCE10-2F is used as the third component,it not only contributes to the improvement of device PCE,but also enhances AVT.This is a comprehensive development for ST-OSCs and helps to solve the contradiction between PCE and AVT.In the PCE10-2F:PM6:Y6 system,with the addition of PM6,the PCE of the device increases.Although it causes a certain degree of decrease in AVT,LUE shows an increasing trend.This means that compared to a slight decrease in AVT,the increase in PCE is greater,resulting in more significant device performance.In the second work,in order to simultaneously improve the PCE and AVT of ST-OSCs.We have proposed a more refined research plan for the PCE10-2F:Y6system.The long chain polymer of the donor is modulated into a short chain polymer through unilateral end capping,which is the concept of small molecule formation and added to the active layer in different proportions.On the one hand,the introduction of small molecules is beneficial for weakening the crystallinity of PCE10-2F and forming a more suitable phase separation size for the active layer of PCE10-2F:Y6.On the other hand,based on the concept of similar compatibility,the addition of oligomers can better improve the film formation morphology of devices.In addition,the oligomer has a lower high occupied molecular orbital（HOMO）energy level,forming a stepped energy level distribution with PCE10-2F and Y6,reducing the potential energy barrier,reducing the non radiation loss during exciton transmission,and helping to improve the V_OCof the two components.Meanwhile,as the amount of oligomers introduced increases,the concentration of the mixed solution decreases,and the thickness of the active layer also decreases,thereby increasing the device transmittance.Finally,we obtained 11.71%PCE,42.83%AVT,and 5.02%LUE.That is to say,in the binary system,we not only broke through the device performance of ST-OSCs once again through the strategy of polymer micromoleculation,but also better solved the inherent contradiction between AVT and PCE in ST-OSCs,further promoting the development of ST-OSCs.更多还原