The development of hole‐transport materials (HTMs) with high mobility, long‐term stability, and comprehensive passivation is significant for simultaneously improving the efficiency and stability of perovskite solar cells (PVSCs). Herein, two donor–acceptor (D–A) conjugated polymers PBTI and PFBTI with alternating benzodithiophene (BDT) and bithiophene imide (BTI) units are successfully developed with desirable hole mobilities due to the good planarity and extended conjugation of molecular backbone. Both copolymers can be employed as HTMs with suitable energy levels and efficient defect passivation. Shortening the alkyl chain of the BTI unit and introducing fluorine atoms on the BDT moiety effectively enhances hole mobility and hydrophobicity of the HTMs, leading to improved efficiency and stability of PVSCs. As a result, the organic–inorganic hybrid PVSCs with PFBTI as the HTM deliver a power conversion efficiency (PCE) of 23.1% with enhanced long‐term operational and ambient stability, which is one of the best efficiencies reported for PVSCs with dopant‐free polymeric HTMs to date. Moreover, PFBTI can be applied in inorganic PVSCs and perovskite/organic tandem solar cells, achieving a high PCE of 17.4% and 22.2%, respectively. These results illustrate the great potential of PFBTI as an efficient and widely applicable HTM for cost‐effective and stable PVSCs.

Organic solar cells (OSCs) have made dramatic advancements during the past decades owing to the innovative material design and device structure optimization, with power conversion efficiencies surpassing 19% and 20% for single‐junction and tandem devices, respectively. Interface engineering, by modifying interface properties between different layers for OSCs, has become a vital part to promote the device efficiency. It is essential to elucidate the intrinsic working mechanism of interface layers, as well as the related physical and chemical processes that manipulate device performance and long‐term stability. In this article, the advances in interface engineering aimed to pursue high‐performance OSCs are reviewed. The specific functions and corresponding design principles of interface layers are summarized first. Then, the anode interface layer, cathode interface layer in single‐junction OSCs, and interconnecting layer of tandem devices are discussed in separate categories, and the interface engineering‐related improvements on device efficiency and stability are analyzed. Finally, the challenges and prospects associated with application of interface engineering are discussed with the emphasis on large‐area, high‐performance, and low‐cost device manufacturing.

Photocatalytic hydrogen evolution is viewed as a promising green strategy to utilize the inexhaustible solar energy and provide clean hydrogen fuels with zeroemission characteristic. The nature of semiconductor-based photocatalysts is the key point to achieve efficient photocatalytic hydrogen evolution. Conjugated materials have been recently emerging as a novel class of photocatalysts for hydrogen evolution and photocatalytic reactions due to their electronic properties can be well controlled via tailormade chemical structures. Hydrophilic conjugated materials, a subgroup of conjugated materials, possess multiple advantages for photocatalytic applications, thus spurring remarkable progress on both material realm and photocatalytic applications. This minireview aims to provide a brief review of the recent developments of hydrophilic conjugated polymers/small molecules for photocatalytic applications, and special concern on the rational molecular design and their impact on photocatalytic performance will be reviewed. Perspectives on the hydrophilic conjugated materials and challenges to their applications in the photocatalytic field are also presented.

The elaborate control of the vertical phase distribution within an active layer is critical to ensuring the high performance of organic solar cells (OSCs), but is challenging. Herein, a self‐stratification active layer is realised by adding a novel polyfluoroalkyl‐containing non‐fullerene small‐molecule acceptor (NFSMA), EH‐C8F17, as the guest into PM6:BTP‐eC9 blend. A favourable vertical morphology was obtained with an upper acceptor‐enriched thin layer and a lower undisturbed bulk heterojunction layer. Consequently, a power conversion efficiency of 18.03 % was achieved, higher than the efficiency of 17.40 % for the device without EH‐C8F17. Additionally, benefiting from the improved charge transport and collection realised by this self‐stratification strategy, the OSC with a thickness of 350 nm had an impressive PCE of 16.89 %. The results of the study indicate that polyfluoroalkyl‐containing NFSMA‐assisted self‐stratification within the active layer is effective for realising an ideal morphology for high‐performance OSCs.

Near‐infrared (NIR) organic photodetectors (OPDs) are competitive candidates for flexible electronics in biomedical imaging and optical communications applications. However, current OPDs still suffer from a low detectivity beyond 1000 nm and a high dark current at bias due to the lack of high‐performance narrow‐bandgap non‐fullerene acceptors (NFAs). In this study, spiro‐conjugated core donor (D) unit is adopted to construct NFAs, SPT‐4F and tSPT‐4F. Comparing with PT‐4F without spiro‐conjugation, the orthogonal spiro‐conjugated planes endow SPT‐4F and tSPT‐4F with more rigid conformation and thus superior intermolecular stacking, resulting in the enhanced absorption beyond 1000 nm. Impressively, tSPT‐4F based device gives the best performance with a dark current of 4.52 × 10−10 A cm−2 under reversed bias of −0.1 V, an external quantum efficiency (EQE) response over 48% at 1010 nm, a detectivity of 1.25 × 1013 Jones and a responsibility of 0.40 A W−1 at 1010 nm. To the best of the authors' knowledge, this is one of the best performed devices reported to date for binary NIR OPDs with response beyond 1000 nm. This study provides a feasible molecular design strategy to develop narrow‐bandgap NFAs with spiro‐conjugation for highly detective NIR OPDs.

We demonstrate a series of direct arylation polycondensated conjugated polyelectrolytes (CPEs) for the application in universal and thickness-insensitive electron transport materials (ETMs) of highly efficient polymer solar cells (PSCs). The...

No abstract

1,4-Azaborine, containing both boron and nitrogen in an aromatic hydrocarbon, displays unique electronic properties compared with its all-carbon analogue and shows great potential as multiresonant thermally activated delayed fluorescence materials....