• Energy Research

AbstractOrganic solar cells based on semiconducting polymers and small molecules have attracted considerable attention in the last two decades. Moreover, the power conversion efficiencies for solution‐processed solar cells containing A–π–D–π–A‐type small molecules and fullerenes have reached 11%. However, the method for designing high‐performance, photovoltaic small molecules still remains unclear. In this review, recent studies on A–π–D–π–A electron‐donating small molecules for organic solar cells are introduced. Moreover, the relationships between molecular properties and device performances are summarized, from which inspiration for the future design of high performance organic solar cells may be obtained.

A 2D–3D perovskite, in which 3D perovskite phase is bridged by 2D perovskite having periodically repeated vertical orientation is reported. It's PCE and stability is better than 3D MAPbI3 and it is an excellent structural strategy to improve stability of perovskite solar cells.

All‐small‐molecule organic solar cells have attracted great interests due to their well‐defined molecular structures and suitability for investigating the relationship between the structure and properties. Herein, two small‐molecule donors (SMDs) based on DTBDT core with chlorine atoms and alkylsilyl side chains, namely, ZR‐Si3 and ZR‐Si4, are synthesized and their respective photovoltaic properties by blending them with IDIC‐4Cl and Y6 are studied. The power conversion efficiency (PCE) based on IDIC‐4Cl is higher than that of Y6 systems due to low driving force between the donors and Y6. Although the two IDIC‐4Cl systems have similar morphology, the PCE of 10.10% is attained based on ZR‐Si4, which is higher than that of ZR‐Si3‐based devices (8.12%). To obtain an in‐depth insight into the structure and performance relationship, single crystals of two SMDs and acceptors are obtained successfully. The shortest π−π stacking distance of 3.43 Å and a transport channel between the layers are observed for ZR‐Si4, which is beneficial for getting better performance.

We systematically investigated the effects of the top substituents on the physicochemical properties of SMAs and achieved the highest PCE for OSCs processed using a non-halogenated solvent without any extra treatment.

By designing new terpolymers, we tuned the molecular orientation to obtain an ordered morphology with suppressed energetic disorder. Thus, we boost the PCE of all-PSCs to over 18%.

To develop ultra-fast charging and long-life lithium ion batteries, a surface-controlled pseudo-capacitive reaction mechanism for organic lithium ion batteries is developed based on a coaxial nanocomposite of an active anthraquinone-based covalent organic framework and CNTs.

Siloxane with low surface tension can regulate the intermolecular interactions, and optimize the phase separation morphology and molecule stacking, finally contributing to an excellent PCE of 16.4% with small energy loss for ASM-OSCs.

Qx-p-4Cl with both apara-fluorinated central unit and chlorinated end groups exhibits enhanced molecular packing, facilitating efficient charge transport, and thus achieving a power conversion efficiency (PCE) of 18.78% when blended with donor PM6.

The treatment of toluene solvent and DTT additive enables the PBQ6:PYF-T-o-based all-PSC devices with PCE up to 17.06%, which is one of the highest value in non-halogenated-processed all-PSCs to date.