| 1. |
- Guo, Yiting, et al.
(author)
-
Effect of Side Groups on the Photovoltaic Performance Based on Porphyrin-Perylene Bisimide Electron Acceptors
- 2018
-
In: ACS Applied Materials and Interfaces. - : AMER CHEMICAL SOC. - 1944-8244 .- 1944-8252. ; 10:38, s. 32454-32461
-
Journal article (peer-reviewed)abstract
- In this work, we developed four porphyrin-based small molecular electron acceptors for non-fullerene organic solar cells, in which different side groups attached to the porphyrin core were selected in order to achieve optimized performance. The molecules contain porphyrin as the core, perylene bisimides as end groups, and the ethynyl unit as the linker. Four side groups, from 2,6-di(dodecyloxy)phenyl to (2-ethylhexyl)thiophen-2-yl, pentadecan-7-yl, and 3,5-di(dodecyloxy)phenyl unit, were applied into the electron acceptors. The new molecules exhibit broad absorption spectra from 300 to 900 nm and high molar extinction coefficients. The molecules as electron acceptors were applied into organic solar cells, showing increased power conversion efficiencies from 1.84 to 5.34%. We employed several techniques, including photoluminescence spectra, electroluminescence spectra, atomic force microscopy, and grazing-incidence wide-angle X-ray to probe the blends to find the effects of the side groups on the photovoltaic properties. We found that the electron acceptors with 2,6-di(dodecyloxy)phenyl units show high-lying frontier energy levels, good crystalline properties, and low nonradiative recombination loss, resulting in possible large phase separation and low energy loss, which is responsible for the low performance. Our results provide a detailed study about the side groups of non-fullerene materials, demonstrating that porphyrin can be used to design electron acceptors toward near-infrared absorption.
|
|
| 2. |
- Li, Cheng, et al.
(author)
-
A diketopyrrolopyrrole-based macrocyclic conjugated molecule for organic electronics
- 2019
-
In: Journal of Materials Chemistry C. - : ROYAL SOC CHEMISTRY. - 2050-7526 .- 2050-7534. ; 7:13, s. 3802-3810
-
Journal article (peer-reviewed)abstract
- In this work, the first diketopyrrolopyrrole (DPP) based donor-acceptor macrocyclic conjugated molecule was developed and its application in organic electronics was systematically studied. Macrocyclic molecules, as a fragment of armchair carbon nanotubes, have emerged as functional materials in materials chemistry, but the materials are always limited to cycloparaphenylenes. Using the donor-acceptor design strategy that has been widely used in high performance conjugated polymers for macrocyclic molecules, it will significantly broaden their species with tunable optical and electrical properties. Herein, we synthesize a well-defined macrocyclic molecule containing four electron-deficient DPP units alternating with electron-rich thiophenes. The new molecule was found to show high solubility, near-infrared absorption spectra and 3D charge transport properties. The new macrocyclic molecule as an electron acceptor was applied to non-fullerene organic solar cells, exhibiting an initial efficiency of 0.49%, while the linear molecule with a similar backbone only showed a very low efficiency of 0.03%. Our results demonstrate that donor-acceptor macrocyclic conjugated materials have great potential application in organic electronics.
|
|
| 3. |
- Chen, Xi, et al.
(author)
-
Ordered Au nanocrystals on a substrate formed by light-induced rapid annealing
- 2014
-
In: Nanoscale. - : Royal Society of Chemistry (RSC). - 2040-3364 .- 2040-3372. ; 6:3, s. 1756-1762
-
Journal article (peer-reviewed)abstract
- Light-induced rapid annealing (LIRA) is a widely used method to modify the morphology and crystallinity of noble metal nanoparticles, and the nanoparticles generally evolve into nanospheres. It is rather challenging to form faceted Au nanocrystals on a substrate using LIRA. Here the formation of spatially ordered Au nanocrystals using a continuous wave infrared laser is reported, assisted by a metamaterial perfect absorber. Faceted Au nanocrystals in truncated-octahedral or multi-twinned geometries can be obtained. The evolution of morphology and crystallinity of the Au nanoparticles during laser annealing is also revealed, where the crystal grain growth and the surface melting are shown to play key roles in nanocrystal formation. The evolution of morphology also gives the freedom of tuning the absorption spectrum of the metamaterial absorber. These findings provide a novel way for tailoring the morphology and crystallinity of metallic nanoparticles and may pave the way to fabricate refined nano-devices in many potential applications for optics, electronics, catalysis, surface-chemistry and biology.
|
|
| 4. |
- Chen, Yiting, et al.
(author)
-
GraspAda: Deep Grasp Adaptation through Domain Transfer
- 2023
-
In: Proceedings - IEEE International Conference on Robotics and Automation. - 1050-4729. - 9798350323658
-
Conference paper (peer-reviewed)abstract
- Learning-based methods for robotic grasping have been shown to yield high performance. However, they rely on expensive-to-acquire and well-labeled datasets. In addition, how to generalize the learned grasping ability across different scenarios is still unsolved. In this paper, we present a novel grasp adaptation strategy to transfer the learned grasping ability to new domains based on visual data using a new grasp feature representation. We present a conditional generative model for visual data transformation. By leveraging the deep feature representational capacity from the well-trained grasp synthesis model, our approach utilizes feature-level contrastive representation learning and adopts adversarial learning on output space. This way we bridge the domain gap between the new domain and the training domain while keeping consistency during the adaptation process. Based on transformed input grasp data via the generator, our trained model can generalize to new domains without any fine-tuning. The proposed method is evaluated on benchmark datasets and based on real robot experiments. The results show that our approach leads to high performance in new scenarios.
|
|
| 5. |
- Currie, Thayne, et al.
(author)
-
SCExAO/CHARIS Direct Imaging Discovery of a 20 au Separation, Low-mass Ratio Brown Dwarf Companion to an Accelerating Sun-like Star
- 2020
-
In: Astrophysical Journal Letters. - : American Astronomical Society. - 2041-8205 .- 2041-8213. ; 904:2
-
Journal article (peer-reviewed)abstract
- We present the direct imaging discovery of a substellar companion to the nearby Sun-like star, HD 33632 Aa, at a projected separation of similar to 20 au, obtained with SCExAO/CHARIS integral field spectroscopy complemented by Keck/NIRC2 thermal infrared imaging. The companion, HD 33632 Ab, induces a 10.5 sigma astrometric acceleration on the star as detected with the Gaia and Hipparcos satellites. SCExAO/CHARIS JHK (1.1-2.4 mu m) spectra and Keck/NIRC2 L-p (3.78 mu m) photometry are best matched by a field L/T transition object: an older, higher-gravity, and less dusty counterpart to HR 8799 cde. Combining our astrometry with Gaia/Hipparcos data and archival Lick Observatory radial velocities, we measure a dynamical mass of 46.4 8 M-J and an eccentricity of e < 0.46 at 95% confidence. HD 33632 Ab's mass and mass ratio (4.0% 0.7%) are comparable to the low-mass brown dwarf GJ 758 B and intermediate between the more massive brown dwarf HD 19467 B and the (near-)planet-mass companions to HR 2562 and GJ 504. Using Gaia to select for direct imaging observations with the newest extreme adaptive optics systems can reveal substellar or even planet-mass companions on solar system-like scales at an increased frequency compared to blind surveys.
|
|
| 6. |
- Gong, Hanmo, et al.
(author)
-
Gold nanoparticle transfer through photothermal effects in a metamaterial absorber by nanosecond laser
- 2014
-
In: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 4, s. 6080-
-
Journal article (peer-reviewed)abstract
- A non-complicated, controllable method of metallic nanoparticle fabrication at low operating light power is proposed. The method is based on laser-induced forward transfer, using a metamaterial absorber as the donor to significantly enhance the photothermal effect and reduce the operating light fluence to 35 mJ/cm(2), which is much lower than that in previous works. A large number of metallic nanoparticles can be transferred by one shot of focused nanosecond laser pulses. Transferred nanoparticles exhibit good size uniformity and the sizes are controllable. The optical properties of transferred particles are characterized by dark-field spectroscopy and the experimental results agree with the simulation results.
|
|
| 7. |
- Li, Qiang, et al.
(author)
-
Efficient directional coupler based on plasmonic waveguide for photonic integrated circuits
- 2010
-
In: International Conference on Optical Communications and Networks 2010. - : IET. - 9781849193146 ; , s. 366-368
-
Conference paper (peer-reviewed)abstract
- Two asymmetric directional couplers, including the dielectric-hybrid plasmonic coupler and the dielectric-metalinsulator-metal plasmonic coupler, are investigated. The proposed hybrid coupler features short coupling length, high coupling efficiency and can be integrated into the siliconbased platform. The applications of these hybrid couplers include the signal routing between plasmonic waveguides and dielectric waveguides in photonic integrated circuits and efficient excitation of plasmonic modes with conventional dielectric modes. Besides, a symmetric directional coupler based on silver nanowires is also demonstrated.
|
|
| 8. |
- Li, Qiang, et al.
(author)
-
Experimental Demonstration of Plasmon Propagation, Coupling, and Splitting in Silver Nanowire at 1550-nm Wavelength
- 2011
-
In: IEEE Journal of Selected Topics in Quantum Electronics. - 1077-260X .- 1558-4542. ; 17:4, s. 1107-1111
-
Journal article (peer-reviewed)abstract
- We experimentally demonstrate silver-nanowire-based plasmonic devices including the nanowaveguide, the nanocoupler, and the nanosplitter at optical communication wavelength of 1550 nm. The plasmon propagation loss in a 300-nm diameter silver nanowire is measured to be 0.3 dB/mu m and the effective propagation length is 14.5 mu m. This loss is comparatively lower than that at 980 nm. Two types of plasmonic functional devices based on the coupling between two silver nanowires, nanocouplers, and nanosplitters, are realized. For the nanocoupler, the experimental results show that the plasmonic modes can be efficiently coupled between two closely positioned nanowires. While for the nanosplitter, the plasmonic mode is split with a power ratio of 2.6:1. These demonstrations experimentally prove the feasibility of extending the operating wavelength of silver-nanowire-based plasmonic devices to current optical communication wavelength with a lower loss, which are thus important steps for potentially utilizing low-loss nanowire-based plasmonic components for photonic integrated circuits.
|
|
| 9. |
- Li, Qiang, et al.
(author)
-
Experimental demonstration of plasmon propagation, coupling, and splitting in silver nanowire at 1550-nm wavelength
- 2011
-
In: IEEE Journal of Selected Topics in Quantum Electronics. - : IEEE. - 1077-260X .- 1558-4542. ; 17:4, s. 1107-1111
-
Journal article (peer-reviewed)abstract
- We experimentally demonstrate silver-nanowire-based plasmonic devices including the nanowaveguide, the nanocoupler, and the nanosplitter at optical communication wavelength of 1550 nm. The plasmon propagation loss in a 300-nm diameter silver nanowire is measured to be 0.3 dB/μm and the effective propagation length is 14.5 μm. This loss is comparatively lower than that at 980 nm. Two types of plasmonic functional devices based on the coupling between two silver nanowires, nanocouplers, and nanosplitters, are realized. For the nanocoupler, the experimental results show that the plasmonic modes can be efficiently coupled between two closely positioned nanowires. While for the nanosplitter, the plasmonic mode is split with a power ratio of 2.6:1. These demonstrations experimentally prove the feasibility of extending the operating wavelength of silver-nanowire-based plasmonic devices to current optical communication wavelength with a lower loss, which are thus important steps for potentially utilizing low-loss nanowire-based plasmonic components for photonic integrated circuits.
|
|
| 10. |
- Li, Qiang, et al.
(author)
-
Silver nanowire based plasmon propagation, coupling and splitting at 1.55 mu m wavelength
- 2011
-
In: Proceedings of SPIE, the International Society for Optical Engineering. - : SPIE. - 0277-786X .- 1996-756X. ; 7986
-
Journal article (peer-reviewed)abstract
- We experimentally demonstrate silver nanowire based plasmonic devices at optical communication wavelength 1.55 mu m. The plasmon propagation loss in a 300 nm diameter silver nanowire is measured to be 0.3 dB/mu m. Two types of plasmonic functional devices based on the coupling between two silver nanowires, nano-couplers and nano-splitters, are realized.
|
|
