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Full-Text Articles in Physics

Extensive Soot Compaction By Cloud Processing From Laboratory And Field Observations, Janarjan Bhandari, Swarup China, Kamal Kant Chandrakar, Greg Kinney, Will Cantrell, Raymond Shaw, Lynn Mazzoleni, Giulia Girotto, Noopur Sharma, Kyle Gorkowski, Stefania Gilardoni, Stefano Decesari, Maria Cristina Facchini, Nicola Zanca, Giulia Pavese, Francesco Esposito, Manvendra K Dubey, Allison C Aiken, Rajan K Chakrabarty, Hans Moosmüller, Timothy B Onasch, Rahul A Zaveri, Barbara V Scarnato, Paulo Fialho, Claudio Mazzoleni Aug 2019

Extensive Soot Compaction By Cloud Processing From Laboratory And Field Observations, Janarjan Bhandari, Swarup China, Kamal Kant Chandrakar, Greg Kinney, Will Cantrell, Raymond Shaw, Lynn Mazzoleni, Giulia Girotto, Noopur Sharma, Kyle Gorkowski, Stefania Gilardoni, Stefano Decesari, Maria Cristina Facchini, Nicola Zanca, Giulia Pavese, Francesco Esposito, Manvendra K Dubey, Allison C Aiken, Rajan K Chakrabarty, Hans Moosmüller, Timothy B Onasch, Rahul A Zaveri, Barbara V Scarnato, Paulo Fialho, Claudio Mazzoleni

Michigan Tech Publications

Soot particles form during combustion of carbonaceous materials and impact climate and air quality. When freshly emitted, they are typically fractal-like aggregates. After atmospheric aging, they can act as cloud condensation nuclei, and water condensation or evaporation restructure them to more compact aggregates, affecting their optical, aerodynamic, and surface properties. Here we survey the morphology of ambient soot particles from various locations and different environmental and aging conditions. We used electron microscopy and show extensive soot compaction after cloud processing. We further performed laboratory experiments to simulate atmospheric cloud processing under controlled conditions. We find that soot particles sampled after ...


Turbulence-Induced Cloud Voids: Observation And Interpretation, Katarzyna Karpinska, Jonathan F. E. Bodenschatz, Szymon P. Malinowski, Jakub L. Nowak, Steffen Risius, Tina Schmeissner, Raymond Shaw, Holger Siebert, Hengdong Xi, Haitao Xu, Eberhard Bodenschatz Apr 2019

Turbulence-Induced Cloud Voids: Observation And Interpretation, Katarzyna Karpinska, Jonathan F. E. Bodenschatz, Szymon P. Malinowski, Jakub L. Nowak, Steffen Risius, Tina Schmeissner, Raymond Shaw, Holger Siebert, Hengdong Xi, Haitao Xu, Eberhard Bodenschatz

Michigan Tech Publications

The phenomenon of “cloud voids”, i.e., elongated volumes inside a cloud that are devoid of droplets, was observed with laser sheet photography in clouds at a mountain-top station. Two experimental cases, similar in turbulence conditions yet with diverse droplet size distributions and cloud void prevalence, are reported. A theoretical explanation is proposed based on the study of heavy inertial sedimenting particles inside a Burgers vortex. A general conclusion regarding void appearance is drawn from theoretical analysis. Numerical simulations of polydisperse droplet motion with realistic vortex parameters and Mie scattering visual effects accounted for can explain the presence of voids ...


Towards All-Solution-Processed Top-Illuminated Flexible Organic Solar Cells Using Ultrathin Ag-Modified Graphite-Coated Poly(Ethylene Terephthalate) Substrates, Shuanglong Wang, Yi Zhao, Hong Lian, Cuiyun Peng, Xuyong Yang, Yulai Gao, Yan Peng, Weixia Lan, Omar Ibrahim Elmi, Didier Stiévenard, Bin Wei, Furong Zhu, Tao Xu Jan 2019

Towards All-Solution-Processed Top-Illuminated Flexible Organic Solar Cells Using Ultrathin Ag-Modified Graphite-Coated Poly(Ethylene Terephthalate) Substrates, Shuanglong Wang, Yi Zhao, Hong Lian, Cuiyun Peng, Xuyong Yang, Yulai Gao, Yan Peng, Weixia Lan, Omar Ibrahim Elmi, Didier Stiévenard, Bin Wei, Furong Zhu, Tao Xu

HKBU Staff Publication

All-solution-processed flexible organic solar cells (FOSCs) with high power conversion efficiency (PCE) are the prerequisite for application in low-cost, large-area, flexible, photovoltaic devices. In this work, high-performance, top-illuminated FOSCs using ultrathin Ag-modified graphite-coated poly(ethylene terephthalate) (PET) substrates are demonstrated. The ultrathin Agmodified graphite/PET substrates have excellent electric conductivity, mechanical flexibility, and easy processability for FOSCs. A PCE of 5.31% for FOSCs, based on the blend system poly[4,8-bis(5-(2-ethylhexyl)thiophen-2-yl) benzo [1,2-b:4,5-b′]dith-iophene-co-3-fluorothieno[3,4- b]thiophene-2-carboxylate]: [6,6]-phenyl-C7l-but-yric acid methyl ester, having a bilayer of MoOx/Ag upper transparent anode ...


Revisiting The Paleomagnetism Of The Neoarchean Uauá Mafic Dyke Swarm, Brazil: Implications For Archean Supercratons, J. Salminen, E. P. Oliveira, Elisa J. Piispa, Aleksey Smirnov, R. I. F. Trindade Dec 2018

Revisiting The Paleomagnetism Of The Neoarchean Uauá Mafic Dyke Swarm, Brazil: Implications For Archean Supercratons, J. Salminen, E. P. Oliveira, Elisa J. Piispa, Aleksey Smirnov, R. I. F. Trindade

Michigan Tech Publications

The original connections of Archean cratons are becoming traceable due to an increasing amount of paleomagnetic data and refined magmatic barcodes. The Uauá block of the northern São Francisco craton may represent a fragment of a major Archean craton. Here, we report new paleomagnetic data from the 2.62 Ga Uauá tholeiitic mafic dyke swarm of the Uauá block in the northern São Francisco craton, Eastern Brazil. Our paleomagnetic results confirm the earlier results for these units, but our interpretation differs. We suggest that the obtained characteristic remanent magnetization for the 2.62 Ga swarm is of primary origin, supported ...


Scale Dependence Of Cloud Microphysical Response To Turbulent Entrainment And Mixing, Bipin Kumar, Paul Gotzfried, Neethl Suresh, Jörg Schumacher, Raymond Shaw Oct 2018

Scale Dependence Of Cloud Microphysical Response To Turbulent Entrainment And Mixing, Bipin Kumar, Paul Gotzfried, Neethl Suresh, Jörg Schumacher, Raymond Shaw

Michigan Tech Publications

The dynamics and lifetime of atmospheric clouds are tightly coupled to entrainment and turbulent mixing. This paper presents direct numerical simulations of turbulent mixing followed by droplet evaporation at the cloud‐clear air interface in a meter‐sized volume, with an ensemble of up to almost half a billion individual cloud water droplets. The dependence of the mixing process on domain size reveals that inhomogeneous mixing becomes increasingly important as the domain size is increased. The shape of the droplet size distribution varies strongly with spatial scale, with the appearance of a pronounced negative exponential tail. The increase of relative ...


Measurement And Modeling Of The Multiwavelength Optical Properties Of Uncoated Flame-Generated Soot, Sara D. Forestieri, Taylor M. Helgestad, Andrew T. Lambe, Lindsay Renbaum-Wolff, Paulo Massoli, Eben S. Cross, Claudio Mazzoleni, Et. Al. Aug 2018

Measurement And Modeling Of The Multiwavelength Optical Properties Of Uncoated Flame-Generated Soot, Sara D. Forestieri, Taylor M. Helgestad, Andrew T. Lambe, Lindsay Renbaum-Wolff, Paulo Massoli, Eben S. Cross, Claudio Mazzoleni, Et. Al.

Michigan Tech Publications

Optical properties of flame-generated black carbon (BC) containing soot particles were quantified at multiple wavelengths for particles produced using two different flames: a methane diffusion flame and an ethylene premixed flame. Measurements were made for (i) nascent soot particles, (ii) thermally denuded nascent particles, and (iii) particles that were coated and then thermally denuded, leading to the collapse of the initially lacy, fractal-like morphology. The measured mass absorption coefficients (MACs) depended on soot maturity and generation but were similar between flames for similar conditions. For mature soot, here corresponding to particles with volume-equivalent diameters >∼160 nm, the MAC and absorption ...


A Method For Computing The Three-Dimensional Radial Distribution Function Of Cloud Particles From Holographic Images, Michael L. Larsen, Raymond Shaw Jul 2018

A Method For Computing The Three-Dimensional Radial Distribution Function Of Cloud Particles From Holographic Images, Michael L. Larsen, Raymond Shaw

Michigan Tech Publications

Reliable measurements of the three-dimensional radial distribution function for cloud droplets are desired to help characterize microphysical processes that depend on local drop environment. Existing numerical techniques to estimate this three-dimensional radial distribution function are not well suited to in situ or laboratory data gathered from a finite experimental domain. This paper introduces and tests a new method designed to reliably estimate the three-dimensional radial distribution function in contexts in which (i) physical considerations prohibit the use of periodic boundary conditions and (ii) particle positions are measured inside a convex volume that may have a large aspect ratio. The method ...


Interlocking Molecular Gear Chains Built On Surfaces, Rundong Zhao, Fei Qi, Zhao Yan-Ling, Klaus E. Hermann, Rui-Qin Zhang, Van Hove Michel A. May 2018

Interlocking Molecular Gear Chains Built On Surfaces, Rundong Zhao, Fei Qi, Zhao Yan-Ling, Klaus E. Hermann, Rui-Qin Zhang, Van Hove Michel A.

HKBU Staff Publication

Periodic chains of molecular gears in which molecules couple with each other and rotate on surfaces have been previously explored by us theoretically using ab initio simulation tools. On the basis of the knowledge and experience gained about the interactions between neighboring molecular gears, we here explore the transmission of rotational motion and energy over larger distances, namely, through a longer chain of gear-like passive “slave” molecules. Such microscopic gears exhibit quite different behaviors compared to rigid cogwheels in the macroscopic world due to their structural flexibility affecting intermolecular interaction. Here, we investigate the capabilities of such gear chains and ...


Electronic And Quantum Transport Properties Of A Graphene-Bn Dot-Ring Hetero-Nanostructure, Max Seel, Ravindra Pandey Apr 2018

Electronic And Quantum Transport Properties Of A Graphene-Bn Dot-Ring Hetero-Nanostructure, Max Seel, Ravindra Pandey

Michigan Tech Publications

Quantum dots, quantum rings, and, most recently, quantum dot-ring nanostructures have been studied for their interesting potential applications in nanoelectronic applications. Here, the electronic properties of a dot-ring hetero-nanostructure consisting of a graphene ring and graphene dot with a hexagonal boron nitride (h-BN) ring serving as barrier between ring and dot are investigated using density functional theory. Analysis of the character of the wave functions near the Fermi level and of the charge distribution of this dot-ring structure and calculations of the quantum transport properties find asymmetry in the conductance resonances leading to asymmetric I–V characteristics which can be ...


Helical Nanoparticle-Induced Enantiospecific Adsorption Of N3 Dyes, Sun Peng, Junjun Liu, Yan Ming, Zhifeng Huang Apr 2018

Helical Nanoparticle-Induced Enantiospecific Adsorption Of N3 Dyes, Sun Peng, Junjun Liu, Yan Ming, Zhifeng Huang

HKBU Staff Publication

It is of fundamental demand for heterogeneous asymmetric catalysis on generating intrinsically chiral metal catalysts without modification of chiral ligands on which molecular substrates can be enantiospecifically adsorbed, which is lack of investigation. Herein, we demonstrate that the anchoring of N3 dyes on plasmonic helical nanoparticles (PhNPs) made of silver through the formation of NCS–Ag contacts leads to enantiospecific adsorption of N3 dyes. The enantiospecific configuration of the immobilized N3 dyes is primarily determined by the helical handedness, and the maximization of the adsorption enantiospecificity occurs at a nominal helical pitch of B15 nm, probably ascribed to the formation ...


Interlocking Mechanism Between Molecular Gears Attached To Surfaces, Rundong Zhao, Yan-Ling Zhao, Fei Qi, Klaus Hermann, Rui-Qing Zhang, Michel A. Van Hove Mar 2018

Interlocking Mechanism Between Molecular Gears Attached To Surfaces, Rundong Zhao, Yan-Ling Zhao, Fei Qi, Klaus Hermann, Rui-Qing Zhang, Michel A. Van Hove

HKBU Staff Publication

While molecular machines play an increasingly significant role in nanoscience research and applications, there remains a shortage of investigations and understanding of the molecular gear (cogwheel), which is an indispensable and fundamental component to drive a larger correlated molecular machine system. Employing ab initio calculations, we investigate model systems consisting of molecules adsorbed on metal or graphene surfaces, ranging from very simple triple-arm gears such as PF3 and NH3 to larger multiarm gears based on carbon rings. We explore in detail the transmission of slow rotational motion from one gear to the next by these relatively simple molecules, so as ...


Omnidirectional And Broadband Light Absorption Enhancement In 2-D Photonic- Structured Organic Solar Cells, Weixia Lan, Yiwen Wang, Singh Jai, Furong Zhu Mar 2018

Omnidirectional And Broadband Light Absorption Enhancement In 2-D Photonic- Structured Organic Solar Cells, Weixia Lan, Yiwen Wang, Singh Jai, Furong Zhu

HKBU Staff Publication

The effect of 2-D photonic-structures on omnidirectional and broadband light absorption enhancement in organic solar cells (OSCs) is analysed using a combination of theoretical simulation and experimental optimization. The photonic structures in the active layers, with a blend system of poly[4,8-bis[(2-ethylhexyl)oxy] benzo[1,2-b:4,5-bA] dithiophene-2, 6-diyl][3-fluoro-2-[(2- ethylhexyl) carbonyl]thieno[3,4-b]-thiophenediyl] :[6,6]- phenyl-C70- butyric-acid-methyl-ester (PTB7:PC70BM), were prepared by the nanoimprint method. It shows that the 2-D photonic structures enable not only broadband but also omnidirectional absorption enhancements in the PTB7:PC70BM-based OSCs over a broader angle range of the ...


Solution-Processable Zno/Carbon Quantum Dots Electron Extraction Layer For Highly Efficient Polymer Solar Cells, Ruqin Zhang, Min Zhao, Zhongqiang Wang, Zongtao Wang, Bo Zhao, Yanqin Miao, Yingjuan Zhou, Hua Wang, Yuying Hao, Guo Chen, Furong Zhu Feb 2018

Solution-Processable Zno/Carbon Quantum Dots Electron Extraction Layer For Highly Efficient Polymer Solar Cells, Ruqin Zhang, Min Zhao, Zhongqiang Wang, Zongtao Wang, Bo Zhao, Yanqin Miao, Yingjuan Zhou, Hua Wang, Yuying Hao, Guo Chen, Furong Zhu

HKBU Staff Publication

In this work, we report the effort to develop high efficiency inverted polymer solar cells (PSCs) by applying a solution processable bilayer ZnO/carbon quantum dots (C-QDs) electron extraction layer (EEL). It is shownthat the use of the bilayerEEL helps to suppress the exciton quenching by passivating the ZnO surface defects in the EEL, leading to an enhanced exciton dissociation, reduced charge recombinationand more efficient charge extraction probability, and thereby achieving high power conversion efficiency (PCE). The inverted PSCs, based on the blend of poly{4,8-bis[(2-ethylhexyl)oxy]benzo[1,2-b:4,5-b']dithiophene-2,6-diyl-alt-3-fluoro-2-[(2-ethylhexyl)carbonyl]thieno[3 ...


Morphology Control Towards Bright And Stable Inorganic Halide Perovskite Light-Emitting Diodes, Fangming Jin, Bo Zhao, Bei Chu, Haifeng Zhao, Zisheng Su, Wenlian Li, Furong Zhu Feb 2018

Morphology Control Towards Bright And Stable Inorganic Halide Perovskite Light-Emitting Diodes, Fangming Jin, Bo Zhao, Bei Chu, Haifeng Zhao, Zisheng Su, Wenlian Li, Furong Zhu

HKBU Staff Publication

The effect of morphology control on the performance of inorganic cesium lead halide based green perovskite light-emitting diodes (PeLEDs) was analyzed. The PeLEDs were prepared using two different formulation approaches: (1) the solution was prepared by dissolving CsPbBr3 powders in dimethyl sulfoxide (DMSO), and (2) the precursor solution was formulated by dissolving CsBr and PbBr2 powders with different molar ratios of CsBr to PbBr2 in DMSO. The peak luminance of 4590 cd/m2 was obtained for PeLEDs made with CsPbBr3-solution, which is 48 and 12 times higher than that of the optimized PeLEDs fabricated using CsBr/PbBr2 precursor solutions with ...


Interface Dipole For Remarkable Efficiency Enhancement In All-Solution-Processable Transparent Inverted Quantum Dot Light-Emitting Diodes, Lixiang Chen, Min-Hsuan Lee, Yiwen Wang, Ying Suet Lau, Ali Asgher Syed, Furong Zhu Feb 2018

Interface Dipole For Remarkable Efficiency Enhancement In All-Solution-Processable Transparent Inverted Quantum Dot Light-Emitting Diodes, Lixiang Chen, Min-Hsuan Lee, Yiwen Wang, Ying Suet Lau, Ali Asgher Syed, Furong Zhu

HKBU Staff Publication

We report our effort to develop high performing all-solution-processable transparent inverted quantum-dot light-emitting diodes (QD-LEDs) by interposing an interface dipole between the ZnO electron-transporting layer (ETL) and the quantum dot light-emitting layer. It shows that the electrostatic interaction between the N+ groups in the polar conjugated polyelectrolyte molecules and the hydroxyl (OH) groups on the ZnO ETL surface creates the interface dipole. The presence of an optimal interface dipole benefits the efficient operation of QD-LEDs in two ways: (1) it effectively reduces the energy barrier at the ETL/QD emisive layer interface for efficient charge injection, and (2) it prevents ...


Molecular Dynamics Study Of Hydrogen Trapping And Helium Clustering In Tungsten, Ashok Gurung Jan 2018

Molecular Dynamics Study Of Hydrogen Trapping And Helium Clustering In Tungsten, Ashok Gurung

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The field of plasma confinement and path toward achieving thermonuclear fusion started with experimental devices like tokamak and has evolved into other more complex variants of magnetic plasma confinement such as stellarator and spherical-tokamaks. As the plasma confinement machines advance towards higher temperature and plasma density (thermonuclear fusion conditions) the role and nature of plasma-wall interaction such as possible edge plasma regimes, particle recycling at the walls and its consequence for erosion, migration and re-deposition of wall material and impurity generation, transport and radiation as well as issues of particle exhaust continues to be a dominant limiting factor due to ...


Establishing A Quality Assurance Routine For Digital Imaging, Sulaiman Rana Al Jan 2018

Establishing A Quality Assurance Routine For Digital Imaging, Sulaiman Rana Al

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In the clinical medical physics field, Quality Assurance (QA) is a fundamental topic to insure patient safety and effective treatment. In recent years, the imaging hardware for diagnostic x-rays has been shifting to fully digital detectors. However, the quality assurance tests for such detectors in the clinical setting is still under development. In the Medical Imaging Department of Kettering Hospital (Kettering, OH), the currently accepted method of performing QA on detectors is to use an extensive set of tests suggested by the manufacturer. This set of tests requires about 90 minutes, which is too long for daily use. The goal ...


Determination Of Dose Effects When Including Attenuation Of The Treatment Table Into Treatment Planning Computer Modeling, Abdullah Alshamrany Jan 2018

Determination Of Dose Effects When Including Attenuation Of The Treatment Table Into Treatment Planning Computer Modeling, Abdullah Alshamrany

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During radiation treatment, the patient commonly lies on a horizontal treatment table called a couch. The material used for the couch is chosen during the manufacturing process so as to minimize the effect of the couch on dose delivery, but it still has an effect. In addition to couch attenuation on the beam, the modern approach of using multiple beam angles for dose delivery makes treatment planning in the presence of the couch more challenging. However, the effect of the couch is not always considered when creating treatment plans, generally due to treatment planning software limitations. In this evaluation, the ...


The Influence Of A Surface On Hysteresis Loops For Single-Domain Ferromagnetic Nanoparticles, Saad Alsari Jan 2018

The Influence Of A Surface On Hysteresis Loops For Single-Domain Ferromagnetic Nanoparticles, Saad Alsari

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The influence of surface effects on a hysteresis loop for single domain, ferromagnetic nanoparticles was examined. Theoretical equations were derived to describe the magnetic behavior of the domains and a MATLAB program was used to solve them. M-H curves were calculated for the case when a magnetic field is applied in the favorable magnetization direction (easy axis). In contrast, the calculations show there were no hysteresis loops when the magnetic field was applied perpendicular to the easy axis. Our studies showed how parameters of the surface such as a associated with saturation magnetization near the surface of nanoparticles and Ks ...


Electromagnetic Properties Of Fractal Antennas, Jordan Jeffrey Ewing Jan 2018

Electromagnetic Properties Of Fractal Antennas, Jordan Jeffrey Ewing

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Finite element method analysis is used to conduct electromagnetic simulations to characterize fractal antennas. This work considers wire (1D) antennas such as the triadic Koch curve, zig zag, and quadratic Koch curve of varying heights, iterations, and cross-sectional areas. Carpet (2D) antennas, including the Sierpinksi carpet, of varying heights, iterations, and deterministic and stochastic iterations are analyzed. The antenna shapes were generated in MATLAB and then modeled with finite element analysis using COMSOL Multiphysics®. The focus of this study is to determine what role various fractal patterns and iterations have on the S11 return loss and far field radiation patterns ...


A Parallel Spectral Method Approach To Model Plasma Instabilities, Kevin S. Scheiman Jan 2018

A Parallel Spectral Method Approach To Model Plasma Instabilities, Kevin S. Scheiman

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The study of solar-terrestrial plasma is concerned with processes in magnetospheric, ionospheric, and cosmic-ray physics involving different particle species and even particles of different energy within a single species. Instabilities in space plasmas and the earth's atmosphere are driven by a multitude of free energy sources such as velocity shear, gravity, temperature anisotropy, electron, and, ion beams and currents. Microinstabilities such as Rayleigh-Taylor and Kelvin-Helmholtz instabilities are important for the understanding of plasma dynamics in presence of magnetic field and velocity shear. Modeling these turbulences is a computationally demanding processes; requiring large memory and suffer from excessively long runtimes ...


Higher-Generation Type Iii-B Rotaxane Dendrimers With Controlling Particle Size In Three-Dimensional Molecular Switching, Chak-Shing Kwan, Rundong Zhao, Michel A. Van Hove, Zongwei Cai, Ken Cham-Fai Leung Jan 2018

Higher-Generation Type Iii-B Rotaxane Dendrimers With Controlling Particle Size In Three-Dimensional Molecular Switching, Chak-Shing Kwan, Rundong Zhao, Michel A. Van Hove, Zongwei Cai, Ken Cham-Fai Leung

HKBU Staff Publication

Type III-B rotaxane dendrimers (T3B-RDs) are hyperbranched macromolecules with mechanical bonds on every branching unit. Here we demonstrate the design, synthesis, and characterization of first to third (G1–G3), and up to the fourth (G4) generation (MW > 22,000 Da) of pure organic T3B-RDs and dendrons through the copper-catalyzed alkyne–azide cycloaddition (CuAAC) reaction. By utilizing multiple molecular shuttling of the mechanical bonds within the sphere-like macromolecule, a collective three-dimensional contract-extend molecular motion is demonstrated by diffusion ordered spectroscopy (DOSY) and atomic force microscopy (AFM). The discrete T3B-RDs are further observed and characterized by AFM, dynamic light scattering (DLS), and ...


Network Dynamics-Based Cancer Panel Stratification For Systemic Prediction Of Anticancer Drug Response, Minsoo Choi, Jue Shi, Yanting Zhu, Ruizhen Yang, Kwang-Hyun Cho Dec 2017

Network Dynamics-Based Cancer Panel Stratification For Systemic Prediction Of Anticancer Drug Response, Minsoo Choi, Jue Shi, Yanting Zhu, Ruizhen Yang, Kwang-Hyun Cho

HKBU Staff Publication

Cancer is a complex disease involving multiple genomic alterations that disrupt the dynamic response of signaling networks. The heterogeneous nature of cancer, which results in highly variable drug response, is a major obstacle to developing effective cancer therapy. Previous studies of cancer therapeutic response mostly focus on static analysis of genome-wide alterations, thus they are unable to unravel the dynamic, network-specific origin of variation. Here we present a network dynamics-based approach to integrate cancer genomics with dynamics of biological network for drug response prediction and design of drug combination. We select the p53 network as an example and analyze its ...


Boosting The Photovoltaic Thermal Stability Of Fullerene Bulk Heterojunction Solar Cells Through Charge Transfer Interactions, Carr Hoi Yi Ho, Huanyang Cao, Yong Lu, Tsz-Ki Lau, Sin Hang Cheung, Ho-Wa Li, Hang Yin, Ka Lok Chiu, Lik-Kuen Ma, Yuanhang Cheng, Sai-Wing Tsang, Xinhui Lu, Shu Kong So, Beng S. Ong Dec 2017

Boosting The Photovoltaic Thermal Stability Of Fullerene Bulk Heterojunction Solar Cells Through Charge Transfer Interactions, Carr Hoi Yi Ho, Huanyang Cao, Yong Lu, Tsz-Ki Lau, Sin Hang Cheung, Ho-Wa Li, Hang Yin, Ka Lok Chiu, Lik-Kuen Ma, Yuanhang Cheng, Sai-Wing Tsang, Xinhui Lu, Shu Kong So, Beng S. Ong

HKBU Staff Publication

Fullerene-based bulk heterojunction organic solar cells (BHJ-OSCs) represent one of the current state-of-the-art organic solar cells. Nonetheless, most of these devices still suffer from adverse performance degradation due to thermally induced morphology changes of active layers. We herein demonstrate that the photovoltaic performance stability of BHJ-OSCs can be profoundly enhanced with an appositely functionalized 9-fluorenylidene malononitrile. The latter, through charge transfer (CT) interactions with a donor polymer, enables the formation of a “frozen” 3-dimensional mesh-like donor polymer matrix, which effectively restrains free movement of embedded fullerene molecules and suppresses their otherwise uncontrolled aggregation. 9-Fluorenylidene malononitrile derivatives with multiple CT interaction ...


Manipulation And Exploitation Of Singlet And Triplet Excitons For Hybrid White Organic Light-Emitting Diodes With Superior Efficiency/Cri/Color Stability, Yanqin Miao, Kexiang Wang, Bo Zhao, Long Gao, Yiwen Wang, Hua Wang, Bingshe Xu, Furong Zhu Dec 2017

Manipulation And Exploitation Of Singlet And Triplet Excitons For Hybrid White Organic Light-Emitting Diodes With Superior Efficiency/Cri/Color Stability, Yanqin Miao, Kexiang Wang, Bo Zhao, Long Gao, Yiwen Wang, Hua Wang, Bingshe Xu, Furong Zhu

HKBU Staff Publication

High performing tetra-chromatic hybrid white organic light-emitting diode (WOLED), with a fluorescent blue emitting layer (EML) of Bis[2-(2-hydroxyphenyl) -pyridine]beryllium (Bepp2) sandwiched between a pair of phosphors-doped hole transporting layer (HTL) and electron transporting layer (ETL), was developed. This was achieved by controlling the location of the green phosphor doped in HTL and yellow phosphor doped in ETL at ∼1 nm away from the HTL/EML and EML/ETL interfaces, and incorporating an ultrathin red phosphorescence layer (< 0.1 nm) in the center of Bepp2 EML. The resulting hybrid WOLED realizes good warm white emission, showing stable electroluminescence spectra with a maximum color rendering index (CRI) of 94 and a low correlated color temperature of 2440−2468 K over a wide voltage range from 5−9 V. Meanwhile, this WOLED also achieves high device efficiency, the maximum current efficiency, power efficiency, and external quantum efficiency up to 34.15 cd/A, 29.51 lm/W, and 17.71 %, respectively. Such high performance is realized through the precise manipulation and effective exploitation of singlet and triplet excitons via novel device design. Moreover, the proposed WOLED also removes the additional interlayers between the fluorescent and phosphorescent emitting regions that are commonly employed in the conventional hybrid WOLEDs, inducing a simplified device structure with reduced heterojunction interfaces, which is very beneficial for promoting the commercial development of WOLEDs.


Origin Of Efficient Inverted Nonfullerene Organic Solar Cells: Enhancement Of Charge Extraction And Suppression Of Bimolecular Recombination Enabled By Augmented Internal Electric Field, Yiwen Wang, Bo Wu, Zhenghui Wu, Zhaojue Lan, Yongfang Li, Maojie Zhang, Furong Zhu Nov 2017

Origin Of Efficient Inverted Nonfullerene Organic Solar Cells: Enhancement Of Charge Extraction And Suppression Of Bimolecular Recombination Enabled By Augmented Internal Electric Field, Yiwen Wang, Bo Wu, Zhenghui Wu, Zhaojue Lan, Yongfang Li, Maojie Zhang, Furong Zhu

HKBU Staff Publication

We report our effort to unravel the origin of efficient operation of nonfullerene organic solar cells (OSCs), based on a poly[4,8-bis(5-(2-ethylhexyl) thiophen-2-yl)benzo[1,2-b;4,5-b′]dithiophene-2,6-diyl-alt-(4-(2-ethylhexyl)-3-fluorothieno[3,4-b]thiophene-)-2-carboxylate-2-6-diyl)](PTB7-Th):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) blend system. The effects of buildup of space charges, charge extraction, and bimolecular recombination processes on the performance and the stability of PTB7-Th:ITIC-based regular and reverse configuration OSCs are analyzed. It ...


Growth, Characterization, And Thin Film Transistor Application Of Ch3nh3pbi3 Perovskite On Polymeric Gate Dielectric Layers, Jenner H. L. Ngai, Johnny K. W. Ho, Rocky K. H. Chan, S. H. Cheung, Louis M. Leung, S. K. So Oct 2017

Growth, Characterization, And Thin Film Transistor Application Of Ch3nh3pbi3 Perovskite On Polymeric Gate Dielectric Layers, Jenner H. L. Ngai, Johnny K. W. Ho, Rocky K. H. Chan, S. H. Cheung, Louis M. Leung, S. K. So

HKBU Staff Publication

Methylammonium-based perovskite compounds are generally grown on conducting or semiconducting substrates for high performance solar cell applications. In this study, we explore the growth of these compounds on insulators and test for their field-effect transistor performance. The key challenge is to find a surface that favors the crystal growth of perovskites without compromising the adhesion of the crystals. A family of methacrylate-based polymers has been identified as the insulators. Onto these insulators, methylammonium lead iodide polycrystalline thin films were grown. Generally, we found that the crystal size in the perovskite layers is well-correlated with the surface hydrophobicity. More hydrophobic polymer ...


Moo3-Induced Oxidation Doping Of Pedot:Pss For High Performing Full-Solution-Processed Inverted Quantum-Dot Light Emitting Diodes, Min-Hsuan Lee, Lixiang Chen, Ning Li, Furong Zhu Oct 2017

Moo3-Induced Oxidation Doping Of Pedot:Pss For High Performing Full-Solution-Processed Inverted Quantum-Dot Light Emitting Diodes, Min-Hsuan Lee, Lixiang Chen, Ning Li, Furong Zhu

HKBU Staff Publication

Full-solution processed inverted quantum dot light-emitting diodes (QD-LEDs) are promising candidates for application in next generation active matrix displays, due to their low-cost solution fabrication processes and easy integration with n-type thin-film transistor backplanes. In this work, we report high performing transparent inverted QD-LEDs using a full-solution processable hybrid composite anode, formulated using poly(3,4-ethylenedioxythiophene): poly(styrenesulfonate) (PEDOT:PSS), solution-processed molybdenum trioxide (s-MoO3), and silver nanowires. The effect of the aqueous s-MoO3 additive in PEDOT: PSS anode on efficient operation of the QD-LEDs was systematically investigated. Our results show that the s-MoO3 additive not only enhances the wettability of ...


Highly Sensitive Near Infrared Organic Phototransistors Based On Conjugated Polymer Nanowire Networks, Yanlian Lei, Ning Li, Wing-Kin Edward Chan, Beng S. Ong, Furong Zhu Sep 2017

Highly Sensitive Near Infrared Organic Phototransistors Based On Conjugated Polymer Nanowire Networks, Yanlian Lei, Ning Li, Wing-Kin Edward Chan, Beng S. Ong, Furong Zhu

HKBU Staff Publication

Highly sensitive near-infrared (NIR) organic phototransistors (OPTs) were fabricated using nanowire network based on a narrow bandgap donor-acceptor (D-A) polymer as the photoactive channel. The D-A polymer nanowire network-based NIR-OPTs exhibit high responsivity of ∼246 A/W under an NIR illumination source (850 nm) with a light intensity of ∼0.1 mW/cm2. This value is over one order of magnitude higher than that of the structurally identical planar D-A polymer thin film OPTs. The high performance of the nanowire network-based phototransistors is attributed to the excellent hole transport ability, reduced density of the structural defects in the polymer nanowires ...


Rabi-Like Splitting From Large Area Plasmonic Microcavity, Fatemeh Hosseini Alast, Guixin Li, K. W. Cheah Aug 2017

Rabi-Like Splitting From Large Area Plasmonic Microcavity, Fatemeh Hosseini Alast, Guixin Li, K. W. Cheah

HKBU Staff Publication

Rabi-like splitting was observed from a hybrid plasmonic microcavity. The splitting comes from the coupling of cavity mode with the surface plasmon polariton mode; anti-crossing was observed alongside the modal conversional channel on the reflection light measurement. The hybrid device consists of a 10x10 mm2 ruled metal grating integrated onto the Fabry-Perot microcavity. The 10x10 mm2 ruled metal grating fabricated from laser interference and the area is sufficiently large to be used in the practical optical device. The larger area hybrid plasmonic microcavity can be employed in polariton lasers and biosensors.