Recent advances in small molecular design for high performance non-fullerene organic solar cells

Abstract

Organic solar cells (OSCs) have become one of the most rapidly developing research fields in the past two decades due to their low cost, light weight, and suitable for large-area...

Regioregular polymerized small-molecule acceptors for high-performance all-polymer solar cells

“…At present, most of the cores used are fused ring, which often involved multistep chemical reactions and high costs. 21 These disadvantages make them unfavorable for industrial application. The non-fused ring core has the advantages of simple synthesis, high yields, and low costs.…”

“…19 Lack of excellent polymer acceptors leads to lower PCEs for all-PSCs than that of SMA-based PSCs. 5,20,21 Further advancements of all-PSCs require new design strategies to develop novel polymer acceptors which should simultaneously possess suitable energy levels, strong light harvesting abilities, and high electron mobility and electron affinity.…”

n-Type polymer electron acceptors for organic solar cells

“…6 According to the type of electron acceptor materials in the active layer of OSCs, they can be divided into fullerene OSCs and non-fullerene OSCs. [7][8][9][10][11][12][13] Fullerene OSCs employ small molecules or polymers with hole transport properties as electron donors and [6,6]-phenyl-C61-butyric acid methyl ester (PC 61 BM), [6,6]-phenyl-C71-butyric acid methyl ester (PC 71 BM) or other fullerene derivatives as electron acceptors. 14,15 Fullerene OSCs have been extensively researched during the first 20 years of the development of OSCs due to the excellent charge transport properties, high electron affinity and the easy-to-control phase separation morphology of fullerene.…”

“…To overcome the intrinsic limitations of electronic energy level regulation and the weak absorption of fullerene acceptors, researchers have designed and synthesised many small-molecule acceptors (SMAs), 7,22 which are alternatives to fullerene acceptors. Zhan et al 90,91 developed A-D-A type SMAs, such as ITIC and IDIC, with the fused ring unit as the central core and the strong electron-deficient unit as the end group.…”

“…These SMAs have a narrow bandgap, strong absorption, and suitable electronic energy levels and could be easily modified through core engineering, side-chain engineering, halogen substitution and symmetry-breaking strategy. 7 With the participation of scientific researchers worldwide, intense investigations have been conducted on the structural tailoring of the molecules and lots of SMAs with new structures and excellent performance have been reported. At present, OSCs based on SMAs can realize a PCE higher than 19%.…”