| 1. |
- Bi, Chenghao, et al.
(författare)
-
Spontaneous Self-Assembly of Cesium Lead Halide Perovskite Nanoplatelets into Cuboid Crystals with High Intensity Blue Emission
- 2019
-
Ingår i: Advanced Science. - : Wiley. - 2198-3844. ; 6:13
-
Tidskriftsartikel (refereegranskat)abstract
- Colloidal all-inorganic perovskite nanocrystals have gained significant attention as a promising material for both fundamental and applied research due to their excellent emission properties. However, reported photoluminescence quantum yields (PL QYs) of blue-emitting perovskite nanocrystals are rather low, mostly due to the fact that the high energy excitons for such wide bandgap materials are easily captured by interband traps, and then decay nonradiatively. In this work, it is demonstrated how to tackle this issue, performing self-assembly of 2D perovskite nanoplatelets into larger size (≈50 nm × 50 nm × 20 nm) cuboid crystals. In these structures, 2D nanoplatelets being isolated from each other within the cuboidal scaffold by organic ligands constitute multiple quantum wells, where exciton localization on potential disorder sites helps them to bypass nonradiative channels present in other platelets. As a result, the cuboid crystals show an extremely high PL QY of 91% of the emission band centered at 480 nm. Moreover, using the same synthetic method, mixed-anion CsPb(Br/Cl) 3 cuboid crystals with blue emission peaks ranging from 452 to 470 nm, and still high PL QYs in the range of 72–83% are produced.
|
|
| 2. |
- Cen, Xiaohong, et al.
(författare)
-
TLR1/2 Specific Small-Molecule Agonist Suppresses Leukemia Cancer Cell Growth by Stimulating Cytotoxic T Lymphocytes
- 2019
-
Ingår i: Advanced Science. - : Wiley. - 2198-3844. ; 6:10
-
Tidskriftsartikel (refereegranskat)abstract
- Toll-like receptor 2 (TLR2) expressed on antigen presenting cells evokes a series of critical cytokines, which favor the development of tumor-specific cytotoxic T lymphocytes (CTLs). Therefore, TLR2 represents an attractive cancer immunotherapeutic target. Here, a synthetic library of 14 000 compounds together with a series of newly developed compounds for NF-κB activation using HEK-Blue hTLR2 cells is initially screened. Following further screening in a variety of cells including HEK-Blue hTLRs reporter cells, murine, and human macrophage cell lines, a potent small molecule agonist 23 (SMU-Z1) is identified, which specifically activates TLR2 through its association with TLR1, with a EC50 of 4.88 ± 0.79 × 10-9 m. Toxicology studies, proinflammatory cytokines (e.g., TNF-α, IL-1β, IL-6, and nitric oxide) and target-protein based biophysical assays demonstrate the pharmacologically relevant characteristics of SMU-Z1. In addition, SMU-Z1 promotes murine splenocyte proliferation and upregulates the expression of CD8+ T cells, NK cells and DCs, which results in a significant antitumor effect in a murine leukemia model. Finally, the induced tumors in three out of seven mice disappear after administration of SMU-Z1. Our studies thus identify a novel and potent TLR1/2 small molecule agonist, which displays promising immune adjuvant properties and antitumor immunity.
|
|
| 3. |
- Du, Jian, et al.
(författare)
-
Iron-Salen Complex and Co2+ Ion-Derived Cobalt-Iron Hydroxide/Carbon Nanohybrid as an Efficient Oxygen Evolution Electrocatalyst
- 2019
-
Ingår i: Advanced Science. - : WILEY. - 2198-3844. ; 6:12
-
Tidskriftsartikel (refereegranskat)abstract
- Metal-salen complexes are widely used as catalysts in numerous fundamental organic transformation reactions. Here, CoFe hydroxide/carbon nanohybrid is reported as an efficient oxygen evolution electrocatalyst derived from the in situ formed molecular Fe-salen complexes and Co2+ ions at a low temperature of 160 degrees C. It has been evidenced that Fe-salen as a molecular precursor facilitates the confined-growth of metal hydroxides, while Co2+ plays a critical role in catalyzing the transformation of organic ligand into nanocarbons and constitutes an essential component for CoFe hydroxide. The resulting Co1.2Fe/C hybrid material requires an overpotential of 260 mV at a current density of 10 mA cm(-2) with high durability. The high activity is contributed to uniform distribution of CoFe hydroxides on carbon layer and excellent electron conductivity caused by intimate contact between metal and nanocarbon. Given the diversity of molecular precursors, these results represent a promising approach to high-performance carbon-based water splitting catalysts.
|
|
| 4. |
- Gerasimov, Jennifer, et al.
(författare)
-
An Evolvable Organic Electrochemical Transistor for Neuromorphic Applications
- 2019
-
Ingår i: Advanced Science. - : Wiley-VCH Verlagsgesellschaft. - 2198-3844. ; 6:7
-
Tidskriftsartikel (refereegranskat)abstract
- An evolvable organic electrochemical transistor (OECT), operating in the hybrid accumulation-depletion mode is reported, which exhibits short-term and long-term memory functionalities. The transistor channel, formed by an electropolymerized conducting polymer, can be formed, modulated, and obliterated in situ and under operation. Enduring changes in channel conductance, analogous to long-term potentiation and depression, are attained by electropolymerization and electrochemical overoxidation of the channel material, respectively. Transient changes in channel conductance, analogous to short-term potentiation and depression, are accomplished by inducing nonequilibrium doping states within the transistor channel. By manipulating the input signal, the strength of the transistor response to a given stimulus can be modulated within a range that spans several orders of magnitude, producing behavior that is directly comparable to short- and long-term neuroplasticity. The evolvable transistor is further incorporated into a simple circuit that mimics classical conditioning. It is forecasted that OECTs that can be physically and electronically modulated under operation will bring about a new paradigm of machine learning based on evolvable organic electronics.
|
|
| 5. |
- Han, Shaobo, et al.
(författare)
-
A Multiparameter Pressure–Temperature–Humidity Sensor Based on Mixed Ionic–Electronic Cellulose Aerogels
- 2019
-
Ingår i: Advanced Science. - : Wiley. - 2198-3844.
-
Tidskriftsartikel (refereegranskat)abstract
- Pressure (P), temperature (T), and humidity (H) are physical key parameters of great relevance for various applications such as in distributed diagnostics, robotics, electronic skins, functional clothing, and many other Internet-of-Things (IoT) solutions. Previous studies on monitoring and recording these three parameters have focused on the integration of three individual single-parameter sensors into an electronic circuit, also comprising dedicated sense amplifiers, signal processing, and communication interfaces. To limit complexity in, e.g., multifunctional IoT systems, and thus reducing the manufacturing costs of such sensing/communication outposts, it is desirable to achieve one single-sensor device that simultaneously or consecutively measures P–T–H without cross-talks in the sensing functionality. Herein, a novel organic mixed ion–electron conducting aerogel is reported, which can sense P–T–H with minimal cross-talk between the measured parameters. The exclusive read-out of the three individual parameters is performed electronically in one single device configuration and is enabled by the use of a novel strategy that combines electronic and ionic Seebeck effect along with mixed ion–electron conduction in an elastic aerogel. The findings promise for multipurpose IoT technology with reduced complexity and production costs, features that are highly anticipated in distributed diagnostics, monitoring, safety, and security applications. © 2019 The Authors.
|
|
| 6. |
- Kushwaha, Khushbu, et al.
(författare)
-
A Record Chromophore Density in High-Entropy Liquids of Two Low-Melting Perylenes: A New Strategy for Liquid Chromophores
- 2019
-
Ingår i: Advanced Science. - : Wiley. - 2198-3844. ; 6:4
-
Tidskriftsartikel (refereegranskat)abstract
- Liquid chromophores constitute a rare but intriguing class of molecules that are in high demand for the design of luminescent inks, liquid semiconductors, and solar energy storage materials. The most common way to achieve liquid chromophores involves the introduction of long alkyl chains, which, however, significantly reduces the chromophore density. Here, strategy is presented that allows for the preparation of liquid chromophores with a minimal increase in molecular weight, using the important class of perylenes as an example. Two synergistic effects are harnessed: (1) the judicious positioning of short alkyl substituents, and (2) equimolar mixing, which in unison results in a liquid material. A series of 1-alkyl perylene derivatives is synthesized and it is found that short ethyl or butyl chains reduce the melting temperature from 278 degrees C to as little as 70 degrees C. Then, two low-melting derivatives are mixed, which results in materials that do not crystallize due to the increased configurational entropy of the system. As a result, liquid chromophores with the lowest reported molecular weight increase compared to the neat chromophore are obtained. The mixing strategy is readily applicable to other pi-conjugated systems and, hence, promises to yield a wide range of low molecular weight liquid chromophores.
|
|
| 7. |
- Liu, Xiaoyu, et al.
(författare)
-
Unveiling Excitonic Dynamics in High-Efficiency Nonfullerene Organic Solar Cells to Direct Morphological Optimization for Suppressing Charge Recombination
- 2019
-
Ingår i: Advanced Science. - : Wiley. - 2198-3844. ; 6:8
-
Tidskriftsartikel (refereegranskat)abstract
- Nonfullerene acceptors (NFAs)-based organic solar cells (OSCs) have recently drawn considerable research interests; however, their excitonic dynamics seems quite different than that of fullerene acceptors-based devices and remains to be largely explored. A random terpolymer of PBBF11 to pair with a paradigm NFA of 3,9-bis(2-methylene-(3-(1,1-dicyanomethylene)-indanone)-5,5,11,11-tetrakis(4-hexylphenyl)-dithieno[2,3-d:2′,3′-d′]-s-indaceno[1,2-b:5,6-b′]dithiophene (ITIC) such that both complementary optical absorption and very small offsets of both highest occupied molecular orbital and lowest unoccupied molecular orbital energy levels are acquired is designed and synthesized. Despite the small energy offsets, efficient electron/hole transfer between PBBF11 and ITIC is both clearly observed from steady-state photoluminescence and transient absorption spectra and also supported by the measured low exciton binding energy in ITIC. Consequently, the PBBF11:ITIC-based OSCs afford an encouraging power conversion efficiency (PCE) of 10.02%. Although the good miscibility of PBBF11 and ITIC induces a homogenous blend film morphology, it causes severe charge recombination. The fullerene acceptor of PC 71 BM with varying loading ratios is therefore added to modulate film morphology to effectively reduce the charge recombination. As a result, the optimal OSCs based on PBBF11:ITIC:PC 71 BM yield a better PCE of 11.4% without any additive or annealing treatment.
|
|
| 8. |
- Petersen, Anne U., et al.
(författare)
-
Solar Energy Storage by Molecular Norbornadiene–Quadricyclane Photoswitches: Polymer Film Devices
- 2019
-
Ingår i: Advanced Science. - : Wiley. - 2198-3844 .- 2198-3844. ; 6:12
-
Tidskriftsartikel (refereegranskat)abstract
- Devices that can capture and convert sunlight into stored chemical energy are attractive candidates for future energy technologies. A general challenge is to combine efficient solar energy capture with high energy densities and energy storage time into a processable composite for device application. Here, norbornadiene (NBD)–quadricyclane (QC) molecular photoswitches are embedded into polymer matrices, with possible applications in energy storing coatings. The NBD–QC photoswitches that are capable of absorbing sunlight with estimated solar energy storage efficiencies of up to 3.8% combined with attractive energy storage densities of up to 0.48 MJ kg −1 . The combination of donor and acceptor units leads to an improved solar spectrum match with an onset of absorption of up to 529 nm and a lifetime (t 1/2 ) of up to 10 months. The NBD–QC systems with properties matched to a daily energy storage cycle are further investigated in the solid state by embedding the molecules into a series of polymer matrices revealing that polystyrene is the preferred choice of matrix. These polymer devices, which can absorb sunlight and over a daily cycle release the energy as heat, are investigated for their cyclability, showing multicycle reusability with limited degradation that might allow them to be applied as window laminates.
|
|
| 9. |
- Rijavec, Tomaž, et al.
(författare)
-
Natural Microbial Communities Can Be Manipulated by Artificially Constructed Biofilms
- 2019
-
Ingår i: Advanced Science. - : Wiley. - 2198-3844 .- 2198-3844. ; 6:22
-
Tidskriftsartikel (refereegranskat)abstract
- Biofouling proceeds in successive steps where the primary colonizers affect the phylogenetic and functional structure of a future microbial consortium. Using microbiologically influenced corrosion (MIC) as a study case, a novel approach for material surface protection is described, which does not prevent biofouling, but rather shapes the process of natural biofilm development to exclude MIC-related microorganisms. This approach interferes with the early steps of natural biofilm formation affecting how the community is finally developed. It is based on a multilayer artificial biofilm, composed of electrostatically modified bacterial cells, producing antimicrobial compounds, extracellular antimicrobial polyelectrolyte matrix, and a water-proof rubber elastomer barrier. The artificial biofilm is constructed layer-by-layer (LBL) by manipulating the electrostatic interactions between microbial cells and material surfaces. Field testing on standard steel coupons exposed in the sea for more than 30 days followed by laboratory analyses using molecular-biology tools demonstrate that the preapplied artificial biofilm affects the phylogenetic structure of the developing natural biofilm, reducing phylogenetic diversity and excluding MIC-related bacteria. This sustainable solution for material protection showcases the usefulness of artificially guiding microbial evolutionary processes via the electrostatic modification and controlled delivery of bacterial cells and extracellular matrix to the exposed material surfaces.
|
|
| 10. |
- Vasudevan, Shashank, et al.
(författare)
-
Leaky Optoelectrical Fiber for Optogenetic Stimulation and Electrochemical Detection of Dopamine Exocytosis from Human Dopaminergic Neurons
- 2019
-
Ingår i: Advanced Science. - : Wiley. - 2198-3844. ; 6:24
-
Tidskriftsartikel (refereegranskat)abstract
- In Parkinson's disease, the degeneration of dopaminergic neurons in substantia nigra leads to a decrease in the physiological levels of dopamine in striatum. The existing dopaminergic therapies effectively alleviate the symptoms, albeit they do not revert the disease progression and result in significant adverse effects. Transplanting dopaminergic neurons derived from stem cells could restore dopamine levels without additional motor complications. However, the transplanted cells disperse in vivo and it is not possible to stimulate them on demand to modulate dopamine release to prevent dyskinesia. In order to address these issues, this paper presents a multifunctional leaky optoelectrical fiber for potential neuromodulation and as a cell substrate for application in combined optogenetic stem cell therapy. Pyrolytic carbon coated optical fibers are laser ablated to pattern micro-optical windows to permit light leakage over a large area. The pyrolytic carbon acts as an excellent electrode for the electrochemical detection of dopamine. Human neural stem cells are genetically modified to express the light sensitive opsin channelrhodopsin-2 and are differentiated into dopaminergic neurons on the leaky optoelectrical fiber. Finally, light leaking from the micro-optical windows is used to stimulate the dopaminergic neurons resulting in the release of dopamine that is detected in real-time using chronoamperometry.
|
|
