| 1. |
- Jiang, Huanxiang, et al.
(författare)
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Appropriate Molecular Interaction Enabling Perfect Balance Between Induced Crystallinity and Phase Separation for Efficient Photovoltaic Blends
- 2020
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Ingår i: ACS Applied Materials and Interfaces. - : American Chemical Society. - 1944-8244 .- 1944-8252. ; 12:23, s. 26286-26292
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Tidskriftsartikel (refereegranskat)abstract
- Fluorination is a promising modification method to adjust the photophysical profiles of organic semiconductors. Notably, the fluorine modification on donor or acceptor materials could impact the molecular interaction, which is strongly related to the morphology of bulk heterojunction (BHJ) blends and the resultant device performance. Therefore, it is essential to investigate how the molecular interaction affects the morphology of BHJ films. In this study, a new fluorinated polymer PBDB-PSF is synthesized to investigate the molecular interaction in both nonfluorinated (ITIC) and fluorinated (IT-4F) systems. The results reveal that the F-F interaction in the PBDB-PSF:IT-4F system could effectively induce the crystallization of IT-4F while retaining the ideal phase separation scale, resulting in outstanding charge transport. On the contrary, poor morphology can be observed in the PBDB-PSF:ITIC system because of the unbalanced molecular interaction. As a consequence, the PBDB-PSF:IT-4F device delivers an excellent power conversion efficiency of 13.63%, which greatly exceeds that of the PBDB-PSF:ITIC device (9.84%). These results highlight manipulating the micromorphology with regard to molecular interaction.
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| 2. |
- Tang, Wei, et al.
(författare)
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17.25% high efficiency ternary solar cells with increased open-circuit voltage using a high HOMO level small molecule guest donor in a PM6:Y6 blend
- 2021
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Ingår i: Journal of Materials Chemistry A. - : Royal Society of Chemistry (RSC). - 2050-7496 .- 2050-7488. ; 9:36, s. 20493-20501
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Tidskriftsartikel (refereegranskat)abstract
- A small molecule donor TiC12 with an asymmetric thieno[3,2-c]isochromene unit is incorporated into the PM6:Y6 system as the third component for constructing ternary organic solar cells (OSCs). It was found that TiC12 played an outstanding role in improvement of open-circuit voltage (V-oc), short-circuit current (J(sc)) and fill factor (FF) for the OSCs. The effects of TiC12 on the absorption, exciton dissociation, charge extraction, bimolecular recombination and morphology of the active layer are analyzed in detail. The synergetic improvement of J(sc), V-oc and FF parameters is realized to generate an advanced power conversion efficiency (PCE) of 17.25% in the optimized PM6 : TiC12 : Y6 (0.9 : 0.1 : 1.2) ternary device. Furthermore, the V-oc is increased in proportion to the added amount of TiC12 in the ternary devices due to reduced disorder and nonradiative energy loss, although the guest donor TiC12 exhibited a higher HOMO level than PM6. This study provides an effective and innovative approach to elevate V-oc and thus PCE for ternary OSCs by introducing a guest small molecule donor with a higher HOMO level and better miscibility with the acceptor.
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