BN-Bond-Embedded Triplet Terpolymers with Small Singlet-Triplet Energy Gaps for Suppressing Non-Radiative Recombination and Improving Blend Morphology in Organic Solar Cells.
Adv Mater
; 35(17): e2211871, 2023 Apr.
Article
en En
| MEDLINE
| ID: mdl-36731510
ABSTRACT
Suppressing the photon energy loss (Eloss ), especially the non-radiative loss, is of importance to further improve the device performance of organic solar cells (OSCs). However, typical π-conjugated semiconductors possess a large singlet-triplet energy gap (ΔEST ), leading to a lower triplet state than charge transfer state and contributing to a non-radiative loss channel of the photocurrent by the triplet state. Herein, a series of triplet polymer donors are developed by introducing a BNIDT block into the PM6 polymer backbone. The high electron affinity of BNIDT and the opposite resonance effect of the BN bond in BNIDT results in a lowered highest occupied molecular orbital (HOMO) and a largely reduced ΔEST . Moreover, the morphology of the active blends is also optimized by fine-tuning the BNIDT content. Therefore, non-radiative recombination via the terminal triplet loss channels and morphology traps is effectively suppressed. The PNB-3 (with 3% BNIDT)L8-BO device exhibits both small ΔEST and optimized morphology, favoring more efficient charge transfer and transport. Finally, the simultaneously enhanced Voc of 0.907 V, Jsc of 26.59 mA cm-2 , and FF of 78.86% contribute to a champion PCE of 19.02%. Therefore, introducing BN bonds into benchmark polymers is a possible avenue toward higher-performance of OSCs.
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01-internacional
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MEDLINE
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En
Revista:
Adv Mater
Asunto de la revista:
BIOFISICA
/
QUIMICA
Año:
2023
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Article