| 1. |
|
|
| 2. |
- Bi, Zhaozhao, et al.
(författare)
-
Individual nanostructure optimization in donor and acceptor phases to achieve efficient quaternary organic solar cells
- 2019
-
Ingår i: Nano Energy. - : ELSEVIER. - 2211-2855 .- 2211-3282. ; 66
-
Tidskriftsartikel (refereegranskat)abstract
- Fullerene derivative (PC71BM) and high crystallinity molecule (DR3TBDTT) are employed into PTB7-Th:FOIC based organic solar cells (OSCs) to cooperate an individual nanostructure optimized quaternary blend. PC71BM functions as molecular adjuster and phase modifier promoting FOIC forming "head-to-head" molecular packing and neutralizing the excessive FOIC crystallites. A multi-scale modified morphology is present thanks to the mixture of FOIC and PC71BM while DR3TBDTT disperses into PTB7-Th matrix to reinforce donors crystal-linity and enhance domain purity. Morphology characterization highlights the importance of individually optimizated nanostructures for donor and acceptor, which contributes to efficient hole and electron transport toward improved carrier mobilities and suppressed non-geminated recombination. Therefore, a power conversion efficiency of 13.51% is realized for a quaternary device which is 16% higher than the binary device (PTB7-Th:FOIC). This work demonstrates that utilizing quaternary strategy for simultaneous optimization of donor and acceptor phases is a feasible way to realize high efficient OSCs.
|
|
| 3. |
- Zhou, Ke, et al.
(författare)
-
Molecular and Energetic Order Dominate the Photocurrent Generation Process in Organic Solar Cells with Small Energetic Offsets
- 2020
-
Ingår i: ACS Energy Letters. - : AMER CHEMICAL SOC. - 2380-8195. ; 5:2, s. 589-596
-
Tidskriftsartikel (refereegranskat)abstract
- Minimizing the energetic offset between the donor (D) and acceptor (A) in organic solar cells (OSCs) is pivotal for reducing the charge-transfer (CT) loss and improving the open-circuit voltage (V-oc). This nevertheless leads to a topic of debate regarding the driving force for the charge separation in OSCs with small energetic offsets. The molecular packing geometries in the active layer determine the energetic levels and trap density, but their relationship with the driving force is seldom considered. Limited by the complicated demixing morphology and inaccurate measurements of energy levels in the prototypical bulk-heterojunction (BHJ) devices, we thereby demonstrate a concise and robust planar-heterojunction model of PM7/N2200 to investigate the origin of driving force for charge generation. It is surprising to note that the device with smaller energy offset shows higher efficiency. Further analysis reveals that a bilayer device with short-range packing PM7 exhibits smaller energetic offsets along with fewer morphological defects and traps compared to its long-range packing counterparts. This molecular packing characteristic diminishes the energetic disorder at the D/A interfaces and inhibits the trap-assisted charge recombination, contributing to the increased short-circuit current (J(SC)) and V-OC. Our results suggest that the energetic offset actually has limited influence on charge separation, while the synergetic control of molecular and energetic order is vital to the photocurrent generation and energy loss reduction in OSCs.
|
|
| 4. |
- Guo, Sihua, et al.
(författare)
-
Toward ultrahigh thermal conductivity graphene films
- 2023
-
Ingår i: 2D Materials. - : IOP Publishing. - 2053-1583. ; 10:1
-
Tidskriftsartikel (refereegranskat)abstract
- With increasing demands of high-performance and functionality, electronics devices generate a great amount of heat. Thus, efficient heat dissipation is crucially needed. Owing to its extremely good thermal conductivity, graphene is an interesting candidate for this purpose. In this paper, a two-step temperature-annealing process to fabricate ultrahigh thermal conductive graphene assembled films (GFs) is proposed. The thermal conductivity of the obtained GFs was as high as 3826 +/- 47 W m(-1) K-1. Extending the time of high-temperature annealing significantly improved the thermal performance of the GF. Structural analyses confirmed that the high thermal conductivity is caused by the large grain size, defect-free stacking, and high flatness, which are beneficial for phonon transmission in the carbon lattice. The turbostratic stacking degree decreased with increasing heat treatment time. However, the increase in the grain size after long heat treatment had a more pronounced effect on the phonon transfer of the GF than that of turbostratic stacking. The developed GFs show great potential for efficient thermal management in electronics devices.
|
|
| 5. |
- Liu, Sirui, et al.
(författare)
-
Design of Hygroscopic Bioplastic Products Stable in Varying Humidities
- 2023
-
Ingår i: Macromolecular materials and engineering. - : Wiley. - 1438-7492 .- 1439-2054. ; 308:2
-
Tidskriftsartikel (refereegranskat)abstract
- Hygroscopic biopolymers like proteins and polysaccharides suffer from humidity-dependent mechanical properties. Because humidity can vary significantly over the year, or even within a day, these polymers will not generally have stable properties during their lifetimes. On wheat gluten, a model highly hygroscopic biopolymer material, it is observed that larger/thicker samples can be significantly more mechanically stable than thinner samples. It is shown here that this is due to slow water diffusion, which, in turn, is due to the rigid polymer structure caused by the double-bond character of the peptide bond, the many bulky peptide side groups, and the hydrogen bond network. More than a year is required to reach complete moisture saturation (≈10 wt.%) in a 1 cm thick plate of glycerol-plasticized wheat gluten, whereas this process takes only one day for a 0.5 mm thick plate. The overall moisture uptake is also retarded by swelling-induced mechanical effects. Hence, hygroscopic biopolymers are better suited for larger/thicker products, where the moisture-induced changes in mechanical properties are smeared out over time, to the extent that the product remains sufficiently tough over climate changes, for example, throughout the course of a year.
|
|
| 6. |
- Yang, Lei, et al.
(författare)
-
Sulfur vs. tellurium: the heteroatom effects on the nonfullerene acceptors
- 2019
-
Ingår i: Science in China Series B. - : SCIENCE PRESS. - 1674-7291 .- 1869-1870. ; 62:7, s. 897-903
-
Tidskriftsartikel (refereegranskat)abstract
- The effect of chalcogen heteroatom variation on donor materials has been systematically investigated. However, this effect on acceptors has rarely been explored. Herein, nonfullerene acceptors BFPSP and BFPTP were reported by simply changing the chalcogen atoms from S to Te. The differences between BFPSP and BFPTP in light absorption, energy levels, excited-state lifetimes, energy loss, charge mobilities, morphology, and photovoltaic properties were systematically investigated to understand the heteroatom effects. More importantly, the electroluminescence spectra, external quantum efficiency of photovoltaics and TD-DFT calculations revealed that the triplet excited state (T-1) in energy of BFPTP equals to the charge transfer (CT) state in PBDB-T:BFPTP, which allows T-1 excitons, generated by intersystem crossing, to split into free charges to contribute to the efficiency. This contribution provides a strategy for tuning the photophysical properties of nonfullerene acceptors and designing high performance triplet materials for OSCs.
|
|
| 7. |
- Zhang, Zhizhong, et al.
(författare)
-
Genetically Predicted Milk Intake and Risk of Neurodegenerative Diseases.
- 2021
-
Ingår i: Nutrients. - : MDPI AG. - 2072-6643. ; 13:8
-
Tidskriftsartikel (refereegranskat)abstract
- Milk intake has been associated with risk of neurodegenerative diseases in observational studies. Nevertheless, whether the association is causal remains unknown. We adopted Mendelian randomization design to evaluate the potential causal association between milk intake and common neurodegenerative diseases, including multiple sclerosis (MS), Alzheimer's disease (AD), amyotrophic lateral sclerosis (ALS), and Parkinson's disease (PD). Genetic associations for neurodegenerative diseases were obtained from the International Multiple Sclerosis Genetics Consortium (n = 80,094), FinnGen consortium (n = 176,899), AD GWAS (n = 63,926), Web-Based Study of Parkinson's Disease (n = 308,518), PDGene (n = 108,990), and ALS GWAS (n = 80,610). Lactase persistence variant rs4988235 (LCT-13910 C > T) was used as the instrumental variable for milk intake. Genetically predicted higher milk intake was associated with a decreased risk of MS and AD and with an increased risk of PD. For each additional milk intake increasing allele, the odds ratios were 0.94 (95% confidence intervals [CI]: 0.91-0.97; p = 1.51 × 10-4) for MS, 0.97 (0.94-0.99; p = 0.019) for AD and 1.09 (95%CI: 1.06-1.12, p = 9.30 × 10-9) for PD. Genetically predicted milk intake was not associated with ALS (odds ratio: 0.97, 95%CI: 0.94-1.01, p = 0.135). Our results suggest that genetically predicted milk intake is associated with a decreased risk of MS and AD but with an increased risk of PD. Further investigations are needed to clarify the underlying mechanisms.
|
|
