Small Molecule Interlayers in Organic Solar Cells

Abstract

This review provides an up‐to‐date review about the small molecule interlayers (SMIs) in organic solar cells (OSCs). Compared to polymer interlayers, SMIs exhibit intrinsic advantages such as easy synthesis and purification, monodispersity, well‐defined chemical structure, and high batch‐to‐batch reproducibility. Recently, various SMIs have been reported with landmark efficiencies of over 10% in both conventional and inverted OSCs, exhibiting promising potential in commercial application. In this review, the authors summarize the progress of SMIs from a device fabrication point of view, paying particular attention to the material categories, molecular design, preparation process, and applicable device structure. In addition, the working mechanisms of different SMIs are also discussed, including the structure–property relationships and the corresponding impact on device performance. Finally, a brief outlook is provided that includes opportunities and challenges in this emerging area.

Nanocomposite of nickel oxide nanoparticles and polyethylene oxide as printable hole transport layer for organic solar cells

“…In the eld of printable organic and hybrid electronics, increasing attention has been recently dedicated to novel interlayers that enable the optimal functioning of the electronic device. [1][2][3][4][5][6][7] These interlayers provide an improved energetic alignment of the device electrodes to the semiconducting active layers, reducing contact resistance effects and providing a more efficient charge injection/extraction. [8][9][10][11][12][13] In recent years, high work-function solution-processed transition metal oxides (TMOs) such as non-stoichiometric nickel oxide (NiO x ), molybdenum oxide (MoO 3 ), vanadium oxide (V 2 O 5 ), and tungsten oxide (WO 3 ) have become promising candidates for hole injection/extraction interlayers for photovoltaic and organic light emitting devices.…”

Efficient Inverted Polymer Solar Cells with ITO Cathode Modified by Zinc Oxide and Polyethylene Oxide Bilayers

“…In the recent years, the PSCs with inverted device structure utilizing ITO as cathode and high‐work‐function metal as anode have been intensively considered due to the better long‐term device stability, and appropriate cathode buffer layer is very critical to improve device performance of inverted PSCs . Various inorganic and organic interfacial materials as cathode buffer layers show good potential to improve device efficiency and stability of inverted PSCs …”

“…[5][6][7][8] Various inorganic and organic interfacial materials as cathode buffer layers show good potential to improve device efficiency and stability of inverted PSCs. [9][10][11][12][13] Zinc oxide (ZnO) with the advantages of easy preparation, good transparency, high electron mobility and environmental stability is typically used as cathode buffer layer for inverted PSCs. [14] ZnO layer can be easily achieved with various methods mainly including sol-gel strategy and nanoparticle approaches, [15][16][17] where ZnO nanoparticles can also be synthesized by different ways.…”

TTA as a potential hole transport layer for application in conventional polymer solar cells

“…It is manifested in the literature that such highly efficient devices are dependent on multiple aspects in terms of architecture design with conventional or inverted structure, manipulation of active layers, buffer layers as well as interfacial layers, which have been investigated in piles of studies [6][7][8][9][10][11] . In particular, as universally agreed, the presence of hole transport layers (HTLs) plays a decisive role in determining device performance of OSCs [12] .…”