Currently,the performance improvement for inverted perovskite solar cells (PVSCs) is mainly limited by the high open circuit voltage (V OC)l oss caused by detrimental nonradiative recombination (NRR) processes.H erein, we report as imple and efficient wayt os imultaneously reduce the NRR processes inside perovskites and at the interface by rationally designing an ew pyridine-based polymer hole-transporting material (HTM), PPY2,w hiche xhibits suitable energy levels with perovskites,high hole mobility,effective passivation of the uncoordinated Pb 2+ and iodide defects,aswell as the capability of promoting the formation of high-quality polycrystalline perovskite films.I na bsence of any dopants,t he inverted PVSCs using PPY2 as the HTM deliver an encouraging PCE up to 22.41 %w ith as mall V OC loss (0.40 V), among the best device performances for inverted PVSCs reported so far. Furthermore, PPY2-based unencapsulated devices showa n excellent long-term photostability,a nd over 97 %o fits initial PCE can be maintained after one sun constant illumination for 500 h.

Squaraine dyes (SQs) are an important class of polymethine dyes with a unique reasonable‐stabilized zwitterionic structure, in which electrons are highly delocalized over the conjugated bridge. These dyes can not only be easily synthesized via a condensation, but also exhibit intense absorption and emission in the visible and near‐infrared region with excellent photochemical stability, making them attractive material candidates for many photoelectric and biomedical applications. Thus, in this review, after an introduction of SQs, the recent advances of SQs in the photovoltaic field are comprehensively summarized including dye‐sensitized solar cells, organic solar cells, and perovskite solar cells. Then, the important advances in the use of SQs as the biosensors, biological imaging, and photodynamic/photothermal therapy reagents in the biomedical field are also discussed. Finally, a summary and outlook will be provided with some new perspectives for the future design of SQs.

No abstract

Unreported 2,3-dicyano-fluoranthene was first prepared as an efficient electron-withdrawing building block for constructing D–A type dopant-free hole transporting materials.

A systematic structure–property correlation study was conducted to preliminarily elucidate an inherent regularity governing the structure of dopant-free HTMs.