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Electron‐carrying polymers are highly desired for various optoelectronic applications but are still scarce. Herein, two anthracene diimide (ADI) polymers with thiophene and bithiophene as comonomer, respectively, are reported as electron acceptor materials in all‐polymer solar cells (all‐PSCs) for the first time. Effects of crystallinity and orientation of two polymer films as well as their blends with different donor polymers on photovoltaic properties are elaborately investigated by grazing‐incidence X‐ray diffraction and photo‐induced force microscopy. It is found that molecular crystallinity and orientation determine the blend film morphology, and the similar high crystallinity and the same face‐on orientation of donor and acceptor polymers are favorable for obtaining excellent photovoltaic performances. With this principle, a suitable donor polymer is singled out to match with the ADI acceptor polymer, offering an impressive efficiency of ≈7% for all‐PSCs. This work demonstrates that ADI polymers are promising as acceptor materials and provides guidelines for screening donor and acceptor polymer combinations for all‐PSCs. [ABSTRACT FROM AUTHOR]

A 2D conjugated polyelectrolyte (CPE), PBDTTh‐TT‐NBr, having the same backbone as the highly efficient donor polymer PTB7‐Th and the quaternary ammonium pendant, is synthesized as a cathode interlayer (CIL) material for PTB7‐Th‐based fullerene and non‐fullerene solar cells. The quaternary ammonium group is connected to the 2D conjugated backbone by a long, flexible alkyl chain, facilitating the modification of cathode via forming interface dipoles. Moreover, compared with another CPE analogue to PTB7, PBDT‐TT‐NBr, without the 2D conjugated backbone, the PBDTTh‐TT‐NBr presents a higher similarity in polymer structure to the donor polymer PTB7‐Th. This feature makes it more compatible with the PTB7‐Th‐based active‐layer film, improving the electron transport. With the PBDTTh‐TT‐NBr as the CIL, devices afford higher performances than those using the PBDT‐TT‐NBr in both fullerene and non‐fullerene systems. This work offers guidance on choosing the CIL material that ought to possess a highly similar structure to the active‐layer component. [ABSTRACT FROM AUTHOR]

A polymeric ionic liquid (PIL) was synthesized from a small-molecule one (MIL, the monomer), and they were used as cathode interlayers in organic solar cells. Compared with the MIL, the PIL can form a more uniform film for full coverage of an active layer and efficient cathode modification, resulting in higher device efficiency and reproducibility. [ABSTRACT FROM AUTHOR]

Abstract: Inspired by the structural feature of the classical hole‐transport material (HTM), Spiro‐OMeTAD, many analogues based on a highly symmetrical spiro‐core were reported for perovskite solar cells (PSCs). However, these HTMs were prone to crystallize because of the high molecular symmetry, forming non‐uniform films, unfavorable for the device stability and large‐area processing. By lowering the symmetry of spiro‐core, we report herein a novel spirobisindane‐based HTM, Spiro‐I, which could form amorphous films with high uniformity and morphological stability. Compared to the Spiro‐OMeTAD‐based PSCs, those containing Spiro‐I exhibit similar efficiencies for small area but higher ones for large area (1 cm2), and especially much higher air stability (retaining 80 % of initial PCE after 2400 h storage without encapsulation). Moreover, the Spiro‐I can be synthesized from a cheap starting material bisphenol A and used with a small amount for the device fabrication. [ABSTRACT FROM AUTHOR]

A dendrimer based on a spirobixanthene core, termed DH1, is designed and synthesized as a hole‐transporting material (HTM) for perovskite solar cells (PSCs). DH1 showing a hyperbranched structure with methoxydiphenylamine carbazole dendrons stretching outward along the para‐phenylene spacer acquires a large molecular size of up to 1.9 nm, which favors good thermal stability and amorphous property. The thus obtained DH1‐based pinhole‐free film as a hole‐transport layer results in a power conversion efficiency of 17.13% and reduced hysteresis behavior of MAPbI3‐based planar PSCs. This work provides the first example of the use of dendrimer‐type HTM for PSC application, demonstrating a promising approach to design HTMs in a quasiglobular dendrimer with a large molecular size. [ABSTRACT FROM AUTHOR]