Efficient Electron Transport Layer Free Small‐Molecule Organic Solar Cells with Superior Device Stability

Bin, Haijun; Wang, J.; Li, Junyu; Wienk, Martijn M.; Janssen, Raj René

doi:10.1002/adma.202008429

Cited by 55 publications

(52 citation statements)

References 54 publications

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“…Compared with the PM6:L14 and PM6:L15‐based binary cells, the ternary device exhibits a higher J ph / J sat value (98.2%) at the maximizing power output voltage, indicating that both efficient exciton dissociation and charge extraction properties mainly contributed to the improved PCE of the ternary blends (Table S6, Supporting Information). [ 42 ] Furthermore, the photoluminescence (PL) spectrum of MBTI is partially covered by the absorption spectrum of L15 (Figure S6a, Supporting Information), implying a possible energy transfer process between two polymer acceptors. [ 43 ] To verify this, the PL spectra of L15 and MBTI neat films, as well as L15:MBTI‐blend films, were measured at the excitation wavelength of 532 nm.…”

Section: Resultsmentioning

confidence: 99%

Regioregular Narrow‐Bandgap n‐Type Polymers with High Electron Mobility Enabling Highly Efficient All‐Polymer Solar Cells

et al. 2021

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Narrow‐bandgap n‐type polymers with high electron mobility are urgently demanded for the development of all‐polymer solar cells (all‐PSCs). Here, two regioregular narrow‐bandgap polymer acceptors, L15 and MBTI, with two electron‐deficient segments are synthesized by copolymerizing two dibrominated fused‐ring electron acceptors (FREA) with distannylated aromatic imide, respectively. Taking full advantage of the FREA and the imide, both polymer acceptors show narrow bandgap and high electron mobility. Benefiting from the more extended absorption, better backbone ordering, and higher electron mobility than those of its regiorandom analog, the L15‐based all‐PSC yields a high power conversion efficiency (PCE) of 15.2% when blended with the polymer donor PM6. More importantly, MBTI incorporating a benzothiophene‐core FREA segment shows relatively higher frontier molecular orbital levels than L15, forming a cascade‐like energy level alignment with L15 and PM6. Based on this, ternary all‐PSCs are designed where MBTI is introduced as a guest into the PM6:L15 host system. Thanks to further optimal blend morphology and more balanced charge transport, the PCE is improved up to 16.2%, which is among the highest values for all‐PSCs. The results demonstrate that combining an FREA and an aromatic imide to construct regioregular narrow‐bandgap polymer acceptors provides an effective approach to fabricate highly efficient all‐PSCs.

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Section: Resultsmentioning

confidence: 99%

Regioregular Narrow‐Bandgap n‐Type Polymers with High Electron Mobility Enabling Highly Efficient All‐Polymer Solar Cells

et al. 2021

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“…But relatively less has been dedicated to efficient NFA-based systems about this topic ( Du et al., 2020 ). To promote the stability of NFA-based OSCs, different strategies including tailoring of NFA ( Du et al., 2020 ; Hu et al., 2020 ; Labanti et al., 2021 ) and donor ( Zhang et al., 2021 ), designing new active materials ( Bin et al., 2020 ), ternary-blend method ( Yang et al., 2020 ), utilization of stabilizer/dopant ( Linglong Ye et al., 2020 ; Zhang et al., 2019 ), and interface engineering ( Lin et al., 2020 ; Yao et al., 2020 ), have been adopted. Focusing on photo-stability, Brabec ( Du et al., 2020 ) and coworkers systematically studied the PM6/derivatives: IT-4F blend systems.…”

Section: Introductionmentioning

confidence: 99%

Efficient organic solar cells with superior stability based on PM6:BTP-eC9 blend and AZO/Al cathode

Yin

Mei

et al. 2021

iScience

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Summary Although efficiency over 18% has been achieved, the real application of organic solar cells is still impeded by inferior stability because of degradation and limited studies. Here we report efficient normal structure organic solar cells delivering promising stability under different conditions, based on PM6:BTP-eC9 blend and AZO/Al cathode. The impact of cathode on device stability is systematically studied by screening the leading electron transporting layers i.e., AZO, PFN-Br, PDINN, and metal electrodes (Al and Ag). Strong correlation between cathode and stability is demonstrated. The optimal AZO/Al-cathode device delivers the best efficiency of 15.76%, with shelf-stability of T83 > 1,200 h, thermal stability of T60 > 300 h, and MPP operational stability of T87 > 500 h. As far as we know, this is the best stability achieved for PM6:Y6/derivative cells in literature so far, based on well-studied simple cathode system and without any tailoring/dopant for the active blend.

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“…[62] However, both devices were very unstable in air and only retained about 50 % of the initial efficiency in 3 h (Figure S10c), indicating that oxygen and water may play additional role in the degradation of OSCs. [63]…”

Section: Stabilitymentioning

confidence: 99%

Dodecacyclic‐Fused Electron Acceptors with Multiple Electron‐Deficient Units for Efficient Organic Solar Cells

Feng

Liu

et al. 2021

ChemSusChem

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Fused aromatic cores in non-fullerene electron acceptors (NFEAs) play a significant role in determining their optoelectronic properties and photovoltaic performance. In this work, a dodecacyclic-fused core with three electron-deficient units is synthesized through a double intramolecular Cadogan reduction cyclization. Terminal groups with different halogen substitution (F or Cl) are grafted onto the dodecacyclic-fused core to afford MS-4F and MS-4Cl, both of which showed strong and broad absorption, narrow bandgaps around 1.40 eV, and variable molecular packing model in pristine and blend films.Photovoltaic performance of solar cells containing MS-4F and MS-4Cl as NFEAs were investigated with resultant power conversion efficiencies (PCEs) of 11.75 % and 11.79 %, respectively. The mechanism study indicates that both of PBDB-T : MS-4F-and PBDB-T : MS-4Cl-based devices displayed high hole and electron mobility values, efficient charge transfer, and low charge recombination etc. These results indicate that designing multiple-fused aromatic cores with multiple electron-deficient units is a promising strategy to obtain high-performance NFEAs.

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Efficient Electron Transport Layer Free Small‐Molecule Organic Solar Cells with Superior Device Stability

Cited by 55 publications

References 54 publications

Regioregular Narrow‐Bandgap n‐Type Polymers with High Electron Mobility Enabling Highly Efficient All‐Polymer Solar Cells

Regioregular Narrow‐Bandgap n‐Type Polymers with High Electron Mobility Enabling Highly Efficient All‐Polymer Solar Cells

Efficient organic solar cells with superior stability based on PM6:BTP-eC9 blend and AZO/Al cathode

Dodecacyclic‐Fused Electron Acceptors with Multiple Electron‐Deficient Units for Efficient Organic Solar Cells

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