Side-chain engineering is an effective strategy to regulate the solubility and packing behavior of organic materials.R ecently,aunique strategy,s o-called terminal sidechain (T-SC) engineering, has attracted mucha ttention in the field of organic solar cells (OSCs), but there is al acko fd eep understanding of the mechanism. Herein, anew noncovalently fused-ring electron acceptor (NFREA) containing two T-SCs (NoCA-5)w as designed and synthesized.I ntroduction of T-SCs can enhance molecular rigidity and intermolecular p-p stacking, which is confirmed by the smaller Stokes shift value, lower reorganization free energy,a nd shorter p-p stacking distance in comparison to NoCA-1.Hence,the NoCA-5-based device exhibits arecordpower conversion efficiency (PCE) of 14.82 %i nl abs and ac ertified PCE of 14.5 %, resulting from ahigh electron mobility,ashort charge-extraction time,asmall Urbache nergy (E u ), and afavorable phase separation. Scheme 1. Several terminal side chains-containing representatives (published and this work).

Noncovalently fused‐ring electron acceptors (NFREAs) have attracted much attention in recent years owing to their advantages of simple synthetic routes, high yields and low costs. However, the efficiencies of NFREAs based organic solar cells (OSCs) are still far behind those of fused‐ring electron acceptors (FREAs). Herein, a series of NFREAs with S⋅⋅⋅O noncovalent intramolecular interactions were designed and synthesized with a two‐step synthetic route. Upon introducing π‐extended end‐groups into the backbones, the electronic properties, charge transport, film morphology, and energy loss were precisely tuned by fine‐tuning the degree of multi‐fluorination. As a result, a record PCE of 14.53 % in labs and a certified PCE of 13.8 % for NFREAs based devices were obtained. This contribution demonstrated that combining the strategies of noncovalent conformational locks and π‐extended end‐group engineering is a simple and effective way to explore high‐performance NFREAs.

In recent years, power conversion efficiency (PCE) of organic solar cells (OSCs) has made significant improvement. A large number of studies were reported to achieve high PCEs through exploring new active layer materials, especially the high efficiency fused ring acceptors (FRAs). Compared with FRAs, another type of so-called unfused-ring acceptors (UFAs), possessing some advantages such as simple synthesis and low cost, have attracted a lot of attention. Herein, a new UFA BTzO-4F, incorporating with a benzotriazole moiety and S•••O intramolecular noncovalent interactions, has been successfully synthesized. The photovoltaic device based on PBDB-T:BTzO-4F achieved a record PCE of 13.8% for UFAs, which indicates that introducing the benzotriazole moiety is an effective strategy for high quality acceptors. Thus, these findings of this work demonstrate the great potential of UFAs for high performance OSCs.

Constructing organic solar cells with stacked structures by sequential deposition (SD) of donor and acceptor film has great potential in industrial production, since it demonstrated little dependence on the...

The rapid advance of fused‐ring electron acceptors (FREAs) has greatly promoted the leap‐forward development of organic solar cells (OSCs). However, the synthetic complexity of FREAs may be detrimental for future commercial applications. Recently, nonfused‐ring electron acceptors (NREAs) have been developed to be a promising candidate to maintain a rational balance between cost and performance, of which the cores are composed of simple fused rings (NREAs‐I) or nonfused rings (NREAs‐II). Moreover, “noncovalently conformational locks”, are used as an effective strategy to enhance the rigidity and planarity of NREAs and improve device performance. Herein, a novel series of NREAs‐II (PhO4T‐1, PhO4T‐2, and PhO4T‐3) is constructed as a valuable platform for exploring the impact of the end group engineering on optoelectronic properties, intermolecular packing behaviors, and device performance. As a result, a high power conversion efficiency of 13.76% is achieved for PhO4T‐3 based OSCs, which is much higher than those of the PhO4T‐1 and PhO4T‐2‐based devices. Compared with several representative FREAs, PhO4T‐3 possesses the highest figure‐of‐merit value of 133.45 based on a cost‐efficiency evaluation. This work demonstrates that the simple‐structured NREAs‐II are promising candidates for low‐cost and high‐performance OSCs.