Harvesting energy directly from sunlight through photovoltaic technology is considered to be one of the most important paths to address the growing energy crisis. Among various photovoltaic technologies, organic photovoltaics (OPVs) have become one of the fastest growing areas over the past few decades, which possess various merits, such as low-cost materials with abundant sources, easily tunable optical bandgaps for efficient sunlight harvesting, solution processing with eco-friendly solvents, and light-weight devices due to ultrathin absorber films. With the booming development of molecular design, morphology control, and device engineering, the power conversion efficiencies (PCEs) of the state-of-the-art OPVs have exceeded 20%, showing great potential for future commercialization.

Looking back on history, polymers play a great role as both light absorbers and interfacial materials, which have heavily impacted the development of OPVs. Therefore, it is our great honor to organize this special issue entitled “Polymer-Related Organic Photovoltaics” in Macromolecular Rapid Communications. The issue assembles 16 original research articles, covering recent advances in molecular designs of electron donor and acceptor materials, modifications of electron transport layers (ETLs), as well as applications in ultrathin and semi-transparent devices.

Based on the consideration of having complementary absorption and matched energy levels with near-infrared electron acceptors, wide-bandgap polymer donor with donor-acceptor (D-A) alternating structure is a key to construct high-performance OPVs. Zhong'an Li and co-workers report a diazabenzo[k]fluoranthene-based D-A type copolymer donor for efficient OPVs, indicating good potential of electron-deficient unit for constructing high-efficiency polymer donors (article 2200276). Chunhui Duan and co-workers prepare a series of ffBX-based terpolymer donors to regulate the polymer solubility, solid state packing, and blend film morphology by controlling the solubilizing side chain content (article 2200591).

In 2017, Li et al.^[1] pioneered the concept of polymerized small molecule acceptors (PSMAs), which led to the booming development of all-polymer OPVs. Chaohua Cui and co-workers investigate effects of different linker unit on the physicochemical and photovoltaic properties of PSMAs, thus yielding a high PCE of 10.19%, with an outstanding open-circuit voltage (V_oc) values of 1.10 V (article 2100925). Another example of realizing a high V_oc beyond 1.0 V is proposed by Erjun Zhou and co-workers who develop a series of A₂-A₁-D-A₁-A₂ type nonfullerene acceptors via the subtle structure modulation (article 2100810).

To address the high cost and complex synthesis of fused-ring electron acceptors (FREAs), nonfused-ring electron acceptors (NFREAs) have recently become a hot topic due to their concise synthetic route and low production cost. Youtian Tao and co-workers report an efficient NFREA in A-D-A’-D-A configuration with a steric BODIPY as the electron deficient A’ core, showing the promising potential of BODIPY in realizing efficient photoactive materials (article 2100828). Bumjoon J. Kim and co-workers report a thermally-stable and efficient OPVs based on a BTz-containing NFREA, benefiting from the enhanced crystallinity of the chlorinated end-groups (article 2200530).

Incorporating a third component in the active layer to achieve ternary OPV devices is a promising strategy towards improving efficiency and stability. Maojie Zhang and co-workers demonstrate a ternary all-polymer OPV with improved efficiency and stability by using two well-miscible polymer donors (article 2200411). Ke Gao and co-workers prepare a high-performance ternary device via incorporating low-cost “technical grade” PCBM, achieving both improvements in PCE and mechanical properties (article 2200139). Junwu Chen and co-workers report an efficient ternary semi-transparent OPV constructed with a wide bandgap (3.0 eV) fluorescent polymer as host donor, a middle bandgap polymer PM6 as guest donor, and a FREA Y6-BO (article 2200139).

Apart from the above-mentioned researches on photoactive materials and appropriate combinations of donor and acceptor materials, interfacial materials also play an important role in charge extraction, transportation, and collection. Kai Zhang and co-workers design an anion-doped thickness-insensitive (ETLs) for efficient OPVs (article 2200190). Bin Zhao and co-workers synthesize polymerized naphthalimide-based ETLs by combining conjugated and nonconjugated units with a reticulated structure in the backbone for inverted OPVs (article 2200119). Yao Liu and co-workers report the synthesis of phosphocholine and sulfobetaine based polymer zwitterions, which can be employed to modify ZnO cathode interlayers for high-performance inverted OPVs (article 2200291). Youngkyoo Kim and co-workers report an ETL material, which consist of poly(ethylene imine) doped with organic acid molecules at various HPSA molar ratios (article 2200264).

Finally, the three last invited research articles deal with morphology regulation and device fabrication. Wei Ma and co-workers enable toluene-processed PM6 film with increased H-type aggregation and crystallinity, leading to the synergistically improved short-circuit current density and V_oc (article 2100871). Long Ye and co-workers investigate multiple cases of simple yet less-explored poly(3-pentylthiophene)-based OPVs, demonstrating the superior tensile properties of polythiophene-based all-polymer blends for the preparation of stretchable devices (article 2200229). Weiwei Li and co-workers fabricate a mechanically and UV light stable ultrathin OPV via semi-embedding silver nanowires in a hydrogen bonds-based polyimide (article 2200432).

Altogether, we would like to thank each contributor to this special issue. We are also grateful for the kind support from the editorial team of Macromolecular Rapid Communications, in particular Editor-in-Chief Dr. Bo Weng. We hope that this issue will provide the audiences with novel insights, stimulate fruitful discussions, and introduce new research ideas to address significant challenges in this emerging area.

通过光伏技术直接从阳光中获取能量被认为是解决日益严重的能源危机的最重要途径之一。在各种光伏技术中，有机光伏 (OPV) 已成为过去几十年增长最快的领域之一，它具有多种优点，例如来源丰富的低成本材料、易于调节的光学带隙以实现高效的阳光采集、溶液处理使用环保溶剂，以及由于超薄吸收膜而导致的轻型设备。随着分子设计、形态控制和器件工程的蓬勃发展，最先进的 OPV 的功率转换效率 (PCE) 已超过 20%，显示出未来商业化的巨大潜力。

回顾历史，聚合物作为光吸收剂和界面材料发挥着重要作用，对OPV的发展产生了重大影响。因此，我们很荣幸在Macromolecular Rapid Communications中组织本期题为“聚合物相关有机光伏”的特刊。该期汇集了 16 篇原创研究文章，涵盖了电子供体和受体材料分子设计、电子传输层 (ETL) 改性以及超薄和半透明器件应用的最新进展。

基于与近红外电子受体具有互补吸收和匹配能级的考虑，具有供体-受体（DA）交替结构的宽带隙聚合物供体是构建高性能OPV的关键。Zhong'an Li 及其同事报告了一种用于高效 OPV 的基于二氮杂苯并 [ k ] 荧蒽的 DA 型共聚物供体，表明缺电子单元具有构建高效聚合物供体的良好潜力（文章 2200276）。Chunhui Duan 及其同事制备了一系列基于 ffBX 的三元共聚物供体，以通过控制增溶侧链含量来调节聚合物溶解度、固态堆积和共混膜形态（文章 2200591）。

2017 年，李等人。^{[ 1 ]}开创了聚合小分子受体 (PSMA) 的概念，导致了全聚合物 OPV 的蓬勃发展。Chaohua Cui 及其同事研究了不同连接单元对 PSMA 物理化学和光伏特性的影响，从而产生了 10.19% 的高 PCE，以及​​ 1.10 V 的出色开路电压 ( Voc ) 值（文章_2100925）。Erjun Zhou 及其同事提出了实现超过 1.0 V 的高V _{oc的另一个示例，他们开发了一系列 A 2} -A ₁ -DA ₁ -A ₂通过微妙的结构调制类型非富勒烯受体（文章 2100810）。

为了解决稠环电子受体（FREAs）成本高、合成复杂的问题，非稠环电子受体（NFREAs）由于其合成路线简洁、生产成本低等优点，近年来成为研究热点。Youtian Tao 及其同事报告了一种高效的 AD-A'-DA 配置的 NFREA，其中空间 BODIPY 作为缺电子 A' 核，展示了 BODIPY 在实现高效光活性材料方面的巨大潜力（文章 2100828）。Bumjoon J. Kim 及其同事报告了一种基于含 BTz 的 NFREA 的热稳定且高效的 OPV，受益于氯化端基的增强结晶度（文章 2200530）。

在有源层中加入第三种成分以实现三元 OPV 器件是提高效率和稳定性的有前途的策略。Maojie Zhang 及其同事展示了一种三元全聚合物 OPV，通过使用两种易混溶的聚合物供体（文章 2200411）提高了效率和稳定性。Ke Gao 及其同事通过结合低成本“技术级”PCBM 制备了高性能三元器件，实现了 PCE 和机械性能的同时提高（文章 2200139）。Junwu Chen 及其同事报告了一种高效的三元半透明 OPV，该 OPV 由宽带隙 (3.0 eV) 荧光聚合物作为主体供体、中带隙聚合物 PM6 作为客体供体和 FREA Y6-BO 构成（文章 2200139）。

除了上述对光活性材料和供体与受体材料的适当组合的研究外，界面材料在电荷提取、传输和收集方面也发挥着重要作用。Kai Zhang 及其同事设计了一种用于高效 OPV 的阴离子掺杂厚度不敏感 (ETL)（文章 2200190）。Bin Zhao 及其同事通过将共轭和非共轭单元与主链中的网状结构相结合来合成基于聚合萘酰亚胺的 ETL，用于反向 OPV（文章 2200119）。Yao Liu 及其同事报告了基于磷酸胆碱和磺基甜菜碱的聚合物两性离子的合成，可用于修饰高性能倒置 OPV 的 ZnO 阴极夹层（文章 2200291）。Youngkyoo Kim 和同事报告了一份 ETL 材料，

最后，最后三篇受邀研究文章涉及形态调控和器件制造。Wei Ma 及其同事使经甲苯处理的 PM6 薄膜具有更高的 H 型聚集和结晶度，从而协同改善短路电流密度和V _oc（文章 2100871）。Long Ye 及其同事研究了多个基于聚（3-戊基噻吩）的 OPV 的简单但探索较少的案例，证明了基于聚噻吩的全聚合物共混物在制备可拉伸设备时具有优异的拉伸性能（文章 2200229）。Weiwei Li 及其同事通过在基于氢键的聚酰亚胺中半嵌入银纳米线来制造机械和紫外光稳定的超薄 OPV（文章 2200432）。

总而言之，我们要感谢本期特刊的每一位撰稿人。也感谢Macromolecular Rapid Communications编辑团队，特别是主编翁博博士的鼎力支持。我们希望本期杂志能为观众提供新颖的见解，激发富有成果的讨论，并引入新的研究思路，以应对这一新兴领域的重大挑战。