15.34% efficiency all-small-molecule organic solar cells with an improved fill factor enabled by a fullerene additive

Abstract

A fullerene additive adjusts the miscibility between donor and acceptor for morphology optimization and reduces bimolecular recombination, assisting significant improvement of fill factor and efficiency.

Reducing VOC loss via structure compatible and high lowest unoccupied molecular orbital nonfullerene acceptors for over 17%‐efficiency ternary organic photovoltaics

“…Hence, Y6 and its derivatives are extensively reported and used in recent research work. [43][44][45][46][47][48][49][50][51][52][53][54][55][56][57][58] For instance, other D-A copolymer donors, such as PTQ10, P2F-EHP, D16, W1, and D18, have been paired with Y6 to achieve excellent PCEs of 15% to 18%. [59][60][61][62][63] Besides, several research groups employed fullerene derivatives and Y6 to construct dual-acceptors ternary OPVs.…”

Moving Alkyl‐Chain Branching Point Induced a Hierarchical Morphology for Efficient All‐Small‐Molecule Organic Solar Cells

“…[ 25–27 ] Therefore, tuning the morphology of the active layer is one of the most critical factors which need to be considered for the performance improvement for ASM‐OSCs. [ 7,22,28–30 ] For matching with the small molecular acceptors such as Y6, we reported a small molecular donor ZR1 based on dithieno[2,3‐d:2ʹ,3ʹ‐dʹ]benzo[1,2‐b:4,5‐bʹ]dithiophene (DTBDT) unit. Binary all‐small‐molecule OSC based on ZR1:Y6 blend achieved the highest efficiency of 14.34% by optimizing their hierarchical morphologies, in which the donor or acceptor rich domains with size up to ca.…”

Precise Control of Phase Separation Enables 12% Efficiency in All Small Molecule Solar Cells

“…[12][13][14][15] Small molecule donors offer a possible solution to this problem. Unlike conjugated polymers, small-molecule organic semiconductors have a well-defined structure and feature negligible batch-to-batch variations after purification, [14][15][16][17][18][19] while large-scale synthesis is facilitated by well-defined catalyst requirements. Due to the uniform molecular structure of its components, SM-OSCs offer high reproducibility in device fabrication and the possibility of vapor deposition, which can enhance stability.…”

“…[20,21] Despite these apparent advantages, many researchers focus on PSCs, because they feature higher PCEs, exceeding 17% recently, than SM-OSCs for which the maximum PCE is presently 15%. [16] As a consequence, compared to the large variety of high-performance polymer donor materials and associated efficient PSCs, the development of small molecule donor materials and their performance in SM-OSCs is somewhat neglected but warrants more attention. The comparatively low efficiency of SM-OSCs is widely attributed to a suboptimal phase separation between the donor and acceptor, likely due to the increased configurational entropy of SM-OSCs and thus much higher critical Flory-Huggins parameter (χ) compared to PSCs, which results in a lower short-circuit current density (J sc ) and fill factor (FF).…”