【作者】 李涛；

【导师】 翁超；

【作者基本信息】 湘潭大学 ， 化学， 2025， 硕士

【摘要】 聚合物太阳能电池(PSCs)作为一种新兴的能量转换技术,因其重量轻、柔性好、半透明以及溶液可加工等优势而受到研究者的广泛关注。活性层形貌对PSCs的光伏性能起着至关重要的作用,因此研究者一直致力于开发调控活性层形貌的方法。通过在活性层中引入合适的添加剂已被证明是一种简单且高效的形貌调控策略。然而,传统的高沸点溶剂添加剂存在剂量敏感性问题,导致器件重现性较差。此外,这些高沸点溶剂难以完全从活性层中去除,残留的添加剂会持续改变活性层形貌,并可能通过光氧化降解显著降低器件的稳定性。基于此,近年来挥发性固体(VS)添加剂被广泛开发用于形貌调控。这类添加剂不仅保留了溶剂添加剂在简化加工以优化活性层形貌方面的优势,还因其剂量不敏感性和优异的挥发性,显著提高了器件的重现性和稳定性。然而,目前报道的高效VS添加剂大多含有卤素,这不仅对人类健康和环境造成潜在威胁,而且含卤素添加剂的合成相对复杂,在一定程度上增加了成本。因此,开发高效、非卤代的VS添加剂以实现对PSCs活性层形貌的有效调控并提升器件性能具有重要意义。本研究的主要内容与结果如下:1.引入了三种熔点和沸点不同的甲基取代萘衍生物,即1-甲基萘(1-MN)、2-甲基萘(2-MN)和2,7-二甲基萘(2,7-MN),将其作为溶剂/固体添加剂应用于PM6:L8-BO体系。这些非卤代添加剂易于获取且成本低廉,同时具备良好的挥发性,能够从活性层中完全去除。其中,VS添加剂2-MN能最优调控活性层形貌,使基于PM6:L8-BO的PSCs的能量转换效率(PCE)从17.15%显著提升至18.70%,明显优于其他两种添加剂处理的器件。器件物理研究揭示其性能的提升主要归因于电荷迁移率、解离/收集效率、电荷提取速率和载流子寿命的增加,以及电荷复合的减少。此外,2-MN作为一种高效VS添加剂,在不同PSCs体系中具有出色的普适性并且有效提升器件的热稳定性。本研究结果表明,甲基取代萘衍生物作为一种低成本、环境友好且高性能的添加剂,能够有效调控活性层形貌,并显著提升PSCs的效率与热稳定性。这对于推动PSCs的大规模工业化生产具有重要意义。2.为了进一步拓展VS添加剂的种类,我们向基于PM6:L8-BO的PSCs活性层中引入了三种结构相似的非卤代VS添加剂——苯酐(PA)、苯并[C]噻吩-1,3-二酮(S-PA)和苯并[C]硒吩-1,3-二酮(Se-PA),以调控其形貌,从而提升PSCs的PCE。PA、S-PA和Se-PA分别含O、S和Se同主族不同元素,其不同的电负性和原子半径有助于揭示结构相似的添加剂与PSCs性能之间的分子结构-光伏性能关系,以及它们对活性层形貌的调控机制。成膜动力学研究表明,这三种添加剂均延长了PM6:L8-BO薄膜形成时间,这有助于在PM6:L8-BO薄膜中形成更有利于电荷传输的微观结构。此外,由于PA、S-PA和Se-PA之间的偶极矩存在差异,这些添加剂与给体和受体材料形成不同的相互作用,从而改变了它们的聚集行为。研究表明,S-PA拥有适中的偶极矩,其与L8-BO和PM6的分子间相互作用更为适宜。经过S-PA处理后的本体异质结(BHJ)薄膜呈现出更加合适的相分离和更精细的结晶度,从而增强激子解离和电荷收集能力,提高了电荷提取速率和载流子寿命,最终实现了更优的填充因子(FF,79.2%)和高的PCE(18.51%)。此外,S-PA同样能提升传统的富勒烯PSCs性能。器件热稳定性测试表明,与未使用添加剂处理的器件相比,三种添加剂处理的器件均表现出略微增加的热稳定性。这项工作不仅丰富了当前非卤VS添加剂的种类,还揭示了同族O,S,Se杂原子取代的添加剂对活性层的不同作用机制。更多还原

【Abstract】 Polymer solar cells(PSCs)have garnered significant attention as an emerging energy conversion technology due to their advantages,including lightweight,flexibility,semi-transparency,and solution-processability.The morphology of the active layer plays a critical role in determining the photovoltaic performance of PSCs.Consequently,researchers have focused on developing methods to control the morphology of the active layer.Introducing suitable additives into the active layer has been demonstrated to be a simple and effective strategy for morphology regulation.However,traditional high-boiling-point solvent additives exhibit dosage sensitivity,resulting in poor device reproducibility.Moreover,these additives are often challenging to fully remove from the active layer during post-treatment processes.Residual additives can continuously alter the active layer morphology and may severely degrade device performance via photo-oxidative degradation.In response,numerous volatile solid(VS)additives have been developed in recent years for morphology control.These VS additives not only retain the advantages of solvent additives in simplifying processing and optimizing the active layer morphology but also enhance device reproducibility and stability due to their dosage insensitivity and superior volatility.Nevertheless,most highly efficient VS additives reported to date contain halogens,which pose potential risks to human health and the environment.Additionally,the synthesis of halogenated additives is relatively complex,increasing costs to some extent.Therefore,the development of efficient non-halogenated VS additives for effectively controlling the morphology of the active layer in PSCs and improving device performance holds substantial research significance.The main research content and results of this study are summarized as follows:1.Three methyl-substituted naphthalene derivatives with varying melting and boiling points,namely 1-methylnaphthalene(1-MN),2-methylnaphthalene(2-MN),and 2,7-dimethylnaphthalene(2,7-MN),were introduced as solvent/solid additives into the PM6:L8-BO system.These non-halogenated additives are readily accessible,cost-effective,and exhibit favorable volatility,ensuring their complete removal from the active layer.Among these,the VS additive 2-MN demonstrates optimal regulation of the active layer morphology,leading to a significant enhancement in the power conversion efficiency(PCE)of PM6:L8-BO-based PSCs from 17.15%to 18.70%,surpassing the performance of devices treated with the other two additives.Device physics investigations reveal that this performance improvement is primarily attributed to enhanced charge mobility,dissociation/collection efficiency,charge extraction rate,and carrier lifetime,as well as reduced charge recombination.Furthermore,2-MN,as an efficient VS additive,exhibits excellent versatility across different PSCs systems and effectively improves the thermal stability of the devices.The findings of this study indicate that methyl-substituted naphthalene derivatives serve as low-cost,environmentally friendly,and high-performance additives capable of effectively modulating the active layer morphology and significantly enhancing the efficiency and thermal stability of PSCs.This holds great significance for advancing the large-scale industrial production of PSCs.2.To further expand the types of VS additives,three non-halogenated VS additives—phthalic anhydride(PA),Benzo[c]thiophene-1,3-dione(S-PA),and Benzo[c]selenophene-1,3-dione(Se-PA)—were incorporated into the photoactive layer of PSCs based on PM6:L8-BO.These additives were employed to regulate the morphology of the active layer,thereby enhancing the PCE of the PSCs.PA,S-PA,and Se-PA contain different elements from the same group—O,S,and Se,respectively.Their varying electronegativities and atomic radii facilitate the elucidation of the molecular structure-photovoltaic performance relationship between structurally similar additives and the performance of PSCs,as well as their regulatory mechanisms on the morphology of the active layer.The film formation kinetics study shows that all three additives prolong the film formation time of the PM6:L8-BO blends,which is conducive to the formation of a more favorable microstructure for charge transport in the PM6:L8-BO films.Additionally,due to variations in dipole moments among PA,S-PA,and Se-PA,these additives interact differently with the donor and acceptor materials,altering their aggregation behaviors.The results indicate that S-PA exhibits a moderate dipole moment,leading to more appropriate intermolecular interactions with L8-BO and PM6.The bulk heterojunction(BHJ)films treated with S-PA demonstrate more optimal phase separation and finer crystallinity,which enhance exciton dissociation and charge collection efficiencies,charge extraction rates and carrier lifetimes.Consequently,this results in an improved fill factor(FF,79.2%)and a high PCE(18.51%).Furthermore,S-PA also enhances the performance of traditional fullerene-based PSCs.Thermal stability tests of the devices reveal that,compared with untreated devices,those treated with the three additives exhibit slightly enhanced thermal stability.This work not only expands the current type of non-halogenated VS additives but also elucidates the distinct action mechanisms of additives featuring O,S,and Se heteroatoms substitution within the active layer.更多还原