Ladder-Type Dithienonaphthalene-Based Small-Molecule Acceptors for Efficient Nonfullerene Organic Solar Cells

Abstract

Two novel small molecule acceptors (DTNIC6 and DTNIC8) based on a ladder-type dithienonaphthalene (DTN) building block with linear (hexyl) or branched (2-ethylhexyl) alkyl substituents are designed and synthesized. Both acceptors exhibit strong and broad absorption in the range from 500 to 720 nm as well as appropriate highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) levels. Replacing the linear hexyl chains with the branched 2-ethylhexyl chains has a large impact on the film morphology of photoactive layers. In the blend film based on DTNIC8 bearing the branched alkyl chains, morphology with well-defined phase separation was observed. This optimal phase morphology yields efficient exciton dissociation, reduced bimolecular recombination, and enhanced and balanced charge carrier mobilities. Benefited from these factors, organic solar cells (OSCs) based on PBDB-T:DTNIC8 deliver a highest power conversion efficiency (PCE) of 9.03% with a high fill factor (FF) of 72.84%. This unprecedented high FF of 72.84% is one of the highest FF values reported for nonfullerene OSCs. Our work not only affords a promising electron acceptor for nonfullerene solar cells but also provides a side-chain engineering strategy toward high performance OSCs.

Facile Synthesis of Polycyclic Aromatic Hydrocarbon (PAH)–Based Acceptors with Fine‐Tuned Optoelectronic Properties: Toward Efficient Additive‐Free Nonfullerene Organic Solar Cells

“…Energy Mater. [28,35] Figure 5d depicts the external quantum efficiency (EQE) spectra of the optimized devices. As a result, a highly attractive PCE of 10.37% was achieved for the pyrene-core-based DTP-IC-4Ph OSCs with a V oc of 0.90 V, a J sc of 17.32 mA cm −2 , and an FF of 0.66.…”

“…[12d,17] However, it is difficult to control the ratio of additives accurately and the device performance reproducibility could be affected adversely. [27] Nevertheless, PAHs have been largely overlooked for developing emerging FREAs, and there have been very few reports in the burgeoning field of nonfullerene solar cells based on PAH building blocks (e.g., naphthalene, fluorene, and dithienopicenocarbazole) (Figure 2), [28] lacking systematic investigations on the structure-property-performance correlations of PAHbased FREAs. [19] Therefore, it is imperative to develop new FREAs with facile chemical synthesis and good compatibility with additive-free fabrication protocol when blended with donor materials.…”

9,9′‐Bifluorenylidene‐Core Perylene Diimide Acceptors for As‐Cast Non‐Fullerene Organic Solar Cells: The Isomeric Effect on Optoelectronic Properties

“…[1] The power conversione fficiencies (PCEs) based on non-fullerene acceptor materials have achieved 13.1 %. [3] Amongn on-fullerene acceptors, perylene diimides (PDIs) derivatives are most commonly used owing to their high electron mobility,g ood electron-acceptinga bility,a nd low energy levels. [3] Amongn on-fullerene acceptors, perylene diimides (PDIs) derivatives are most commonly used owing to their high electron mobility,g ood electron-acceptinga bility,a nd low energy levels.…”

Side‐Chain Impact on Molecular Orientation of Organic Semiconductor Acceptors: High Performance Nonfullerene Polymer Solar Cells with Thick Active Layer over 400 nm

“…[1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16] Compared with traditional fullerene acceptors such as [6,6]-phenyl-C61/C71-butyric acid methyl ester (PC 61 BM/PC 71 BM), PSCs based on the n-OS acceptors have shown great potential in device performance and device stability. [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16] Compared with traditional fullerene acceptors such as [6,6]-phenyl-C61/C71-butyric acid methyl ester (PC 61 BM/PC 71 BM), PSCs based on the n-OS acceptors have shown great potential in device performance and device stability.…”