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As a class of predominantly used cathode interlayers (CILs) in organic solar cells (OSCs), perylene‐diimide (PDI)‐based polymers exhibit intriguing characteristics of excellent charge transporting capacity and suitable energy levels. Despite that, PDI‐based CILs with satisfied film‐forming ability and adequate solvent resistance are rather rare, which not only limits the further advance of OSC performances but also hinders the practical use of PDI CILs. Herein, we designed and synthesized two non‐conjugated PDI polymers for achieving high power conversion efficiency (PCE) in diverse types of OSCs. The utilization of oligo (ethylene glycol) (OEG) linkage enhanced the n‐doping effect of PDI polymers, leading to an improved ability of the CIL to reduce work function and improve electron transporting capability. Moreover, the introduction of the non‐ionic OEG chain effectively improve the wetting property and solvent resistance of PDI polymers, so the PPDINN CIL can withstand diverse processing conditions in fabricating different OSCs, including conventional, inverted and blade‐coated devices. The binary OSC with conventional structure using PPDINN CIL showed a PCE of 18.6 %, along with an improved device stability. Besides, PPDINN is compatible with the large‐area blade‐coating technique, and a PCE of 16.6 % was achieved in the 1‐cm2 OSC where a blade‐coated PPDINN was used. [ABSTRACT FROM AUTHOR]

Comprehensive Summary: Compared to electron transporting layer materials, the species and numbers of hole transporting layer (HTL) materials for organic solar cells (OSCs) are rare. The development of HTL materials with excellent hole collection ability and non‐corrosive nature is a long‐standing issue in the field of OSCs. Herein, we designed and synthesized a series of conjugated polyelectrolytes (CPEs) with continuously varied energy levels toward HTL materials for efficient OSCs. Through a "mutual doping" treatment, we obtained a CPE composite PCT‐F:POM with a WF of 5.48 eV and a conductivity of 1.56 х 10–3 S/m, meaning that a good hole collection ability can be expected for PCT‐F:POM. The OSC modified by PCT‐F:POM showed a high PCE of 18.0%, which was superior to the reference device with PEDOT:PSS. Moreover, the PCT‐F:POM‐based OSC could maintain 91% of the initial PCE value after storage of 20 d, meaning that the long‐term stability of OSCs is improved by incorporating the PCT‐F:POM HTL. In addition, PCT‐F:POM possesses good compatibility with large‐area processing technique; i.e., a PCT‐F:POM HTL was processed by the blade‐coating method for fabricating 1 cm2 OSC, and a PCE of 15.1% could be achieved. The results suggest the promising perspective of PCT‐F:POM in practical applications. [ABSTRACT FROM AUTHOR]

High‐performance organic cathode interlayers (CILs) play a crucial role in the advance of organic solar cells (OSCs). However, organic CILs have exhibited inferior performances to their inorganic counterparts over a long time, due to the inherent shortcoming of poor charge transporting capability. Here, we designed and synthesized a perylene‐diimide (PDI) zwitterion PDI‐B as high‐performance organic CIL for OSCs. We revealed that an obvious H‐aggregate of PDI‐B was formed during the solution processing, thereby significantly enhancing the charge transporting capability of the CIL. Compared to the classic PDINN, the π–π stacking distance of PDI‐B was reduced from 4.2 Å to 3.9 Å, which further facilitated the charge transport. Consequently, PDI‐B showed a high conductivity of 1.81×10−3S/m; this is comparable to that of inorganic CILs. The binary OSC showed an elevated PCE of 19.23 %, which is among the highest PCE values for binary OSCs. Benefitting from improved solvent resistance and good compatibility with large‐area processing method of PDI‐B, the photovoltaic performances of inverted and 1‐cm2 OSC were significantly improved. The results from this work provide a new approach of optimizing the condensed structure of PDI film to boost the charge conductivity, opening an avenue to develop high‐performance PDI‐based CILs. [ABSTRACT FROM AUTHOR]