Recent progress in cathode interlayer materials for non‐fullerene organic solar cells

Abstract

Non‐fullerene acceptors are currently a hot research area in the development of organic solar cells (OSCs). At present, the‐state‐of‐the‐art power conversion efficiency (PCE) of non‐fullerene organic solar cells (NF‐OSCs) with single and multiple‐junction has surpassed 18% and 19%, respectively. The cathode interlayer (CIL) plays a significant role in the improvement of PCE and the stability of OSCs. Recently, a large number of CIL materials have been employed in OSCs. This review summarizes the recent progress of CIL materials and systematically describes their impact on the device efficiency and stability in single‐junction NF‐OSCs. Firstly, the functions, key requirements, and distinctive features of CILs when used in NF‐OSCs are summarized. Afterward, some big families of materials including metal oxides, metal salts/complexes, small molecules, polymers, composites/hybrids are presented as CIL for NF‐OSCs. Finally, the scale‐up techniques, conclusion, and future challenges regarding CIL in NF‐OSCs are elucidated.

Surface‐Engineered Ti3C2Tx with Tunable Work Functions for Highly Efficient Polymer Solar Cells

“…[34] Compared with Ti 3 C 2 T x , D-Ti 3 C 2 T x exhibits a well-matched band alignment, which can reduce the carrier barrier height. [10,35] Furthermore, D-Ti 3 C 2 T x can promote the electron transport but block hole benefiting from the dipole strength formed by NH 2 and OH. [10,36] In case of R-Ti 3 C 2 T x , the downshift of Femi level can promote hole transport but blocking electron.…”

Conjugated oxazole‐based interfacial materials for efficient and stable inverted polymer solar cell with an efficiency of 16.52%

“…In particular, zinc oxide (ZnO) interlayers are the most commonly used electron transporting layer for the fabrication of inverted PSCs due to their high electron mobility, excellent optical transparency, and low work function. However, not only ZnO would cause a quick photo‐induced degradation of non‐fullerene acceptors 20,21 when exposed to UV light but also require a long time annealing at high temperatures for high quality films 23 . Moreover, defects are observed in ZnO films, which act as charge recombination centres and electron trap sites in PSCs.…”

“…However, not only ZnO would cause a quick photo-induced degradation of non-fullerene acceptors 20,21 when exposed to UV light but also require a long time annealing at high temperatures for high quality films. 23 Moreover, defects are observed in ZnO films, which act as charge recombination centres and electron trap sites in PSCs. The insertion of an interlayer between ZnO and the photoactive layer can be used to prevent unwanted chemical reactions and passivate the traps and defects between the two layers.…”

Natural Product Betulin‐Based Insulating Polymer Filler in Organic Solar Cells

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Organic solar cells (OSCs) have been made great progress recently due to the innovations in device engineering, photo-physics, and novel materials. [1][2][3][4] The multicomponent strategy, one of the device engineering methods to expand the absorption range and/or optimize the microstructure of the photoactive layer, has been widely employed to realize high-efficiency OSCs. [5][6][7][8] Up to date, the power conversion efficiency (PCEs) of the state-of-the-art OSCs with ternary heterojunction has approached 19%.

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