| 1. |
- Cai, Zekai, et al.
(författare)
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Charge photogeneration dynamics in non-fullerene polymer solar cells with fluorinated and non-fluorinated acceptors
- 2024
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Ingår i: Journal of Chemical Physics. - 0021-9606. ; 160:7
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Tidskriftsartikel (refereegranskat)abstract
- In this work, charge photogeneration and recombination processes of PM6:IDIC-4F and PM6:IDIC blend films were investigated by the steady-state and time-resolved spectroscopies, as well as the time-dependent density functional theory calculations. The peaks in absorption and photoluminescence (PL) spectra of IDIC and IDIC-4F solutions were assigned by combining the experiment and the simulation of UV-vis absorption and PL spectra. For neat acceptor films, the exciton diffusion length of neat IDIC and IDIC-4F films was estimated as ∼28.9 and ∼19.9 nm, respectively. For PM6-based blend films, we find that the fluorine substitution engineering on the IDIC acceptor material can increase the phase separate size of acceptor material in blend films, resulting in the reduction of dissociation efficiencies of acceptor excitons. In addition, we find that the charge recombination in PM6:IDIC-4F is dominated by bimolecular recombination, in comparison to geminate type carrier recombination in PM6:IDIC blend films. In addition, we find that thermal annealing treatment has a weak influence on carrier recombination but slightly reduces the exciton dissociation efficiency of acceptor in PM6:IDIC blend films, leading to a slightly reduced power conversion efficiency of PM6:IDIC solar cells. These results may shed light on the design of high-performance semiconductor molecules for application in solar cells.
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| 2. |
- Du, Mulong, et al.
(författare)
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Cyp2a6 activity and cigarette consumption interact in smoking-related lung cancer susceptibility
- 2024
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Ingår i: Cancer Research. - : American Association For Cancer Research (AACR). - 0008-5472 .- 1538-7445. ; 84:4, s. 616-625
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Tidskriftsartikel (refereegranskat)abstract
- Cigarette smoke, containing both nicotine and carcinogens, causes lung cancer. However, not all smokers develop lung cancer, highlighting the importance of the interaction between host susceptibility and environmental exposure in tumorigenesis. Here, we aimed to delineate the interaction between metabolizing ability of tobacco carcinogens and smoking intensity in mediating genetic susceptibility to smoking-related lung tumorigenesis. Single-variant and gene-based associations of 43 tobacco carcinogen–metabolizing genes with lung cancer were analyzed using summary statistics and individual-level genetic data, followed by causal inference of Mendelian randomization, mediation analysis, and structural equation modeling. Cigarette smoke–exposed cell models were used to detect gene expression patterns in relation to specific alleles. Data from the International Lung Cancer Consortium (29,266 cases and 56,450 controls) and UK Biobank (2,155 cases and 376,329 controls) indicated that the genetic variant rs56113850 C>T located in intron 4 of CYP2A6 was significantly associated with decreased lung cancer risk among smokers (OR = 0.88, 95% confidence interval = 0.85–0.91, P = 2.18 X 10-16), which might interact (Pinteraction = 0.028) with and partially be mediated (ORindirect = 0.987) by smoking status. Smoking intensity accounted for 82.3% of the effect of CYP2A6 activity on lung cancer risk but entirely mediated the genetic effect of rs56113850. Mechanistically, the rs56113850 T allele rescued the downregulation of CYP2A6 caused by cigarette smoke exposure, potentially through preferential recruitment of transcription factor helicase-like transcription factor. Together, this study provides additional insights into the interplay between host susceptibility and carcinogen exposure in smoking-related lung tumorigenesis.
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| 3. |
- Feng, Junyi, et al.
(författare)
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Aggregation-Induced Emission in a Polymeric Photovoltaic Donor Material
- 2022
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Ingår i: Journal of Physical Chemistry C. - : American Chemical Society (ACS). - 1932-7447 .- 1932-7455. ; 126:48, s. 20275-20283
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Tidskriftsartikel (refereegranskat)abstract
- In this work, we report the aggregation-induced emission in a polymeric donor material poly(bis(2-butyloctyl)[2,2′:5′,2″-terthiophene]-4,4″-dicarboxylate-5,5′-diyl-vinylene) (PTVT-T), which exhibits a high device performance for the application of photovoltaics. Time-dependent density functional theory calculations and steady-state and time-resolved spectroscopy have been employed to reveal the underlying emission mechanism. We find that the aggregation of the PTVT-T polymer chain in solution increases the exciton luminescence lifetime and exciton emission quantum yield, which is related to the effective torsional inhibition of carbon-carbon single bonds. Compared with the aggregates in solution, the exciton emission quantum yield of the aggregates in PTVT-T film is reduced. It is attributable to exciton delocalization caused by the improvement of molecular planarity in film. We also observe that the as-cast film and thermally annealed film show distinctly different emission behaviors. This work can shed light on designing optoelectronic polymer materials with the integration of photovoltaic and light-emitting functions.
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| 4. |
- Feng, Junyi, et al.
(författare)
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The Role of Energy Offsets on Charge Photogeneration Dynamics in Y-Series Molecules-Based Polymer Solar Cells
- 2023
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Ingår i: Solar RRL. - 2367-198X. ; 7:16
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Tidskriftsartikel (refereegranskat)abstract
- Recent research has revealed that low-energy offset polymer solar cells (PSCs) are capable of a power conversion efficiency of over 19%. However, it is unclear how energy offsets and the charge photogeneration process are correlated. Herein, the effect of energy offsets on charge photogeneration dynamics for Y-series molecules (Y5, Y6, Y10, and BTP-4F-12)-based PSCs with the variations of the lowest unoccupied molecular orbital energy offsets (ΔELUMO) of 0.11–0.42 eV and the highest occupied molecular orbital energy offsets (ΔEHOMO) of 0.08–0.23 eV utilizing steady-state and time-resolved spectroscopies is studied. The steady-state measurement shows that the probability of photoluminescence quenching via energy transfer for the donor exciton reduces with the increasing ΔELUMO. It is found that even in PM6:Y6 with the highest ΔELUMO, ≈18% of PM6 exciton dissociated via the path of “energy transfer first and then hole transfer,” manifesting the energy transfer also plays a vital role in the process of exciton dissociation. Furthermore, it is found that the PM6 exciton can efficiently dissociate under the ΔELUMO of 0.11 eV. After photoexcitation of the Y-series molecule acceptors, the exciton dissociation efficiency enhances with the increase of ΔEHOMO. Besides, the higher energy offsets, the lower charge recombination rate in the ultrafast timescale has been found from the transient absorption measurement. These findings reveal that energy offsets are important for charge photogeneration and recombination in an ultrafast timescale for Y-series molecule-based PSCs, which may shed light on the design of high-performance PSCs.
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| 5. |
- Wen, Guanzhao, et al.
(författare)
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Energy level offsets determine the interplay between charge and energy transfer in all-small-molecule organic solar cells
- 2023
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Ingår i: Chemical Engineering Journal. - 1385-8947. ; 475
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Tidskriftsartikel (refereegranskat)abstract
- All-small-molecule organic solar cells (ASM OSCs) hold great promise in OSCs owing to their defined structures, simple purification, and good reproducibility, but are challenging for further improved efficiency. The energy level strategy has been broadly applied to obtain a better performance; however, a comprehensive understanding of the effects of energy level offset on photoexcitation dynamics in ASM OSCs is rarely studied. Herein, for Y-series molecules (Y6, Y10, Y5, and BTP-4F-12) based ASM OSCs, the effect of energy level offset on charge photogeneration was investigated using steady-state and time-resolved spectroscopies. We found that both energy and charge transfer could occur in blend films. A method to quantitatively analyze the contribution of charge and energy transfer processes was developed. For BTR-Cl:Y6 with the highest LUMO level offset, ∼ 23% of photogenerated excitons in donor dissociated via “energy transfer and the subsequent charge transfer” pathway, suggesting that the energy transfer in blend films should also be considered. And for the hole transfer, the excitons in Y-series molecules can only be effectively dissociated when the HOMO energy level offset is higher than 0.11 eV. Besides, a higher energy level offset would also suppress carrier recombination in ultrafast timescale. These results may shed light on the design of ASM OSCs.
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