Showing papers on "Ternary operation published in 2016"

Ternary Weight Networks

Abstract: We introduce ternary weight networks (TWNs) - neural networks with weights constrained to +1, 0 and -1. The Euclidian distance between full (float or double) precision weights and the ternary weights along with a scaling factor is minimized. Besides, a threshold-based ternary function is optimized to get an approximated solution which can be fast and easily computed. TWNs have stronger expressive abilities than the recently proposed binary precision counterparts and are thus more effective than the latter. Meanwhile, TWNs achieve up to 16$\times$ or 32$\times$ model compression rate and need fewer multiplications compared with the full precision counterparts. Benchmarks on MNIST, CIFAR-10, and large scale ImageNet datasets show that the performance of TWNs is only slightly worse than the full precision counterparts but outperforms the analogous binary precision counterparts a lot.

Trained Ternary Quantization

Abstract: Deep neural networks are widely used in machine learning applications. However, the deployment of large neural networks models can be difficult to deploy on mobile devices with limited power budgets. To solve this problem, we propose Trained Ternary Quantization (TTQ), a method that can reduce the precision of weights in neural networks to ternary values. This method has very little accuracy degradation and can even improve the accuracy of some models (32, 44, 56-layer ResNet) on CIFAR-10 and AlexNet on ImageNet. And our AlexNet model is trained from scratch, which means it's as easy as to train normal full precision model. We highlight our trained quantization method that can learn both ternary values and ternary assignment. During inference, only ternary values (2-bit weights) and scaling factors are needed, therefore our models are nearly 16x smaller than full-precision models. Our ternary models can also be viewed as sparse binary weight networks, which can potentially be accelerated with custom circuit. Experiments on CIFAR-10 show that the ternary models obtained by trained quantization method outperform full-precision models of ResNet-32,44,56 by 0.04%, 0.16%, 0.36%, respectively. On ImageNet, our model outperforms full-precision AlexNet model by 0.3% of Top-1 accuracy and outperforms previous ternary models by 3%.

Versatile ternary organic solar cells: a critical review

Abstract: The power conversion efficiency (PCE) of organic solar cells has been constantly refreshed in the past ten years from 4% up to 11% due to the contribution from the chemists on novel materials and the physicists on device engineering. For practical applications, a single bulk heterojunction structure may be the best candidate due to the cell with a high PCE, easy fabrication and low cost. Recently, ternary solar cells have attracted much attention due to enhanced photon harvesting by using absorption spectral or energy level complementary materials as the second donor or acceptor based on a single bulk heterojunction structure. For better promoting the development of ternary solar cells, we summarize the recent progress of ternary solar cells and try our best to concise out the scientific issues in preparing high performance ternary solar cells.

Ternary Metal Phosphide with Triple-Layered Structure as a Low-Cost and Efficient Electrocatalyst for Bifunctional Water Splitting

Abstract: Development of low-cost, high-performance, and bifunctional electrocatalysts for water splitting is essential for renewable and clean energy technologies. Although binary phosphides are inexpensive, their performance is not as good as noble metals. Adding a third metal element to binary phosphides (Ni-P, Co-P) provides the opportunity to tune their crystalline and electronic structures and thus their electrocatalytic properties. Here, ternary phosphide (NiCoP) films with different nickel to cobalt ratios via an electrodeposition technique are synthesized. The films have a triple-layered and hierarchical morphology, consisting of nanosheets in the bottom layer, ≈90–120 nm nanospheres in the middle layer, and larger spherical particles on the top layer. The ternary phosphides exhibit versatile activities that are strongly dependent on the Ni/Co ratios and Ni0.51Co0.49P film is found to have the best electrocatalytic activities for both hydrogen evolution reactions and oxygen evolution reactions. The high performance of the ternary phosphide film is attributed to enhanced electric conductivity so that reaction kinetics is accelerated, enlarged surface area due to the hierarchical and three-layered morphology, and increased local electric dipole so that the energy barrier for the water splitting reaction is lowered.

Designing ternary blend bulk heterojunction solar cells with reduced carrier recombination and a fill factor of 77

Abstract: In recent years the concept of ternary blend bulk heterojunction (BHJ) solar cells based on organic semiconductors has been widely used to achieve a better match to the solar irradiance spectrum, and power conversion efficiencies beyond 10% have been reported. However, the fill factor of organic solar cells is still limited by the competition between recombination and extraction of free charges. Here, we design advanced material composites leading to a high fill factor of 77% in ternary blends, thus demonstrating how the recombination thresholds can be overcome. Extending beyond the typical sensitization concept, we add a highly ordered polymer that, in addition to enhanced absorption, overcomes limits predicted by classical recombination models. An effective charge transfer from the disordered host system onto the highly ordered sensitizer effectively avoids traps of the host matrix and features an almost ideal recombination behaviour. Carrier recombination in organic solar cells usually limits their optoelectronic performance, in particular their fill factor. Gasparini et al show that adding an ordered polymer to a ternary blend reduces carrier recombination, achieving a fill factor of 77%.

Constructing a novel ternary Fe(III)/graphene/g-C3N4 composite photocatalyst with enhanced visible-light driven photocatalytic activity via interfacial charge transfer effect

Abstract: Interfacial charge transfer effect (IFCT) was introduced into g-C3N4 by grafting Fe(III) species on its surface via a simple impregnation method. It has been shown that the obtained Fe(III)-grafted g-C3N4 photocatalyst exhibited enhanced visible-light absorption, reduced charge recombination and improved photocatalytic activity as compared with those of g-C3N4, due to the interfacial charge transfer between the Fe(III) species and g-C3N4. Furthermore, a novel ternary Fe(III)/graphene/g-C3N4 photocatalyst was successfully constructed by integrating graphene into the binary Fe(III)/g-C3N4 composite as the electron mediator. It has been found that the introduction of graphene made the Fe species show well distribution, smaller size and relatively high content in the ternary photocatalyst as compared with those in the binary one, revealing a synergistic effect between the Fe(III) species and graphene existed in the ternary photocatalyst. Consequently, the photocatalytic activity of the ternary Fe(III)/graphene/g-C3N4 photocatalyst was superior to that of the binary one, originating from its stronger visible-light absorption and more reduced charge combination. The ternary composite that consists of transition metal, graphene and g-C3N4 represents a new kind of high-efficiency visible-light-driven photocatalysts for water disinfection.

Ternary-Blend Polymer Solar Cells Combining Fullerene and Nonfullerene Acceptors to Synergistically Boost the Photovoltaic Performance

Abstract: A ternary-blend strategy is presented to surmount the shortcomings of both fullerene derivatives and nonfullerene small molecules as acceptors for the first time. The optimal ternary device shows a high power conversion efficiency (PCE) of 10.4%. Moreover, a significant enhancement in PCE (≈35%) relative to both of the binary reference devices, which has never been achieved before in high-efficiency ternary devices, is demonstrated.

Ternary Organic Solar Cells Based on Two Compatible Nonfullerene Acceptors with Power Conversion Efficiency >10%

Abstract: Two different nonfullerene acceptors and one copolymer are used to fabricate ternary organic solar cells (OSCs). The two acceptors show unique interactions that reduce crystallinity and form a homogeneous mixed phase in the blend film, leading to a high efficiency of ≈10.3%, the highest performance reported for nonfullerene ternary blends. This work provides a new approach to fabricate high-performance OSCs.

Strongly Coupled Ternary Hybrid Aerogels of N-deficient Porous Graphitic-C3N4 Nanosheets/N-Doped Graphene/NiFe-Layered Double Hydroxide for Solar-Driven Photoelectrochemical Water Oxidation.

Abstract: Developing photoanodes with efficient sunlight harvesting, excellent charge separation and transfer, and fast surface reaction kinetics remains a key challenge in photoelectrochemical water splitting devices. Here we report a new strongly coupled ternary hybrid aerogel that is designed and constructed by in situ assembly of N-deficient porous carbon nitride nanosheets and NiFe-layered double hydroxide into a 3D N-doped graphene framework architecture using a facile hydrothermal method. Such a 3D hierarchical structure combines several advantageous features, including effective light-trapping, multidimensional electron transport pathways, short charge transport time and distance, strong coupling effect, and improved surface reaction kinetics. Benefiting from the desirable nanostructure, the ternary hybrid aerogels exhibited remarkable photoelectrochemical performance for water oxidation. Results included a record-high photocurrent density that reached 162.3 μA cm–2 at 1.4 V versus the reversible hydrogen e...

11% Efficient Ternary Organic Solar Cells with High Composition Tolerance via Integrated Near-IR Sensitization and Interface Engineering.

Abstract: Highly efficient electron extraction is achieved by using a photoconductive cathode interlayer in inverted ternary organic solar cells (OSCs) where a near-IR absorbing porphyrin molecule is used as the sensitizer. The OSCs show improved device performance when the ratio of the two donors varies in a large region and a maximum power conversion efficiency up to 11.03% is demonstrated.

Trained Ternary Quantization

Abstract: Deep neural networks are widely used in machine learning applications. However, the deployment of large neural networks models can be difficult to deploy on mobile devices with limited power budgets. To solve this problem, we propose Trained Ternary Quantization (TTQ), a method that can reduce the precision of weights in neural networks to ternary values. This method has very little accuracy degradation and can even improve the accuracy of some models (32, 44, 56-layer ResNet) on CIFAR-10 and AlexNet on ImageNet. And our AlexNet model is trained from scratch, which means it's as easy as to train normal full precision model. We highlight our trained quantization method that can learn both ternary values and ternary assignment. During inference, only ternary values (2-bit weights) and scaling factors are needed, therefore our models are nearly 16x smaller than full-precision models. Our ternary models can also be viewed as sparse binary weight networks, which can potentially be accelerated with custom circuit. Experiments on CIFAR-10 show that the ternary models obtained by trained quantization method outperform full-precision models of ResNet-32,44,56 by 0.04%, 0.16%, 0.36%, respectively. On ImageNet, our model outperforms full-precision AlexNet model by 0.3% of Top-1 accuracy and outperforms previous ternary models by 3%.

Stability and electronic properties of new inorganic perovskites from high-throughput ab initio calculations

Abstract: Using a high-throughput approach based on density functional theory, we perform an extensive study of possible ABX3 perovskites, where X is a non-metal and A and B span a large portion of the periodic table. We calculate the ternary phase diagram for each composition and we discuss the thermodynamic stability of perovskite phases. We find a large number of ABX3 perovskites, which are still absent from available databases, and which are stable with respect to decomposition into known ternary, binary or elementary phases. For these structures, we then calculate electronic band gaps, hole effective masses, and the spontaneous ferroelectric and magnetic polarization, which are relevant material properties for a number of specific applications in photovoltaics, transparent contacts, piezoelectrics, and magnetoelectrics. Some of our novel perovskites exhibit promising properties for applications.

A ternary Cu2O-Cu-CuO nanocomposite: a catalyst with intriguing activity.

Abstract: In this work, the syntheses of Cu2O as well as Cu(0) nanoparticle catalysts are presented. Copper acetate monohydrate produced two distinctly different catalyst particles with varying concentrations of hydrazine hydrate at room temperature without using any surfactant or support. Then both of them were employed separately for 4-nitrophenol reduction in aqueous solution in the presence of sodium borohydride at room temperature. To our surprise, it was noticed that the catalytic activity of Cu2O was much higher than that of the metal Cu(0) nanoparticles. We have confirmed the reason for the exceptionally high catalytic activity of cuprous oxide nanoparticles over other noble metal nanoparticles for 4-nitrophenol reduction. A plausible mechanism has been reported. The unusual activity of Cu2O nanoparticles in the reduction reaction has been observed because of the in situ generated ternary nanocomposite, Cu2O–Cu–CuO, which rapidly relays electrons and acts as a better catalyst. In this ternary composite, highly active in situ generated Cu(0) is proved to be responsible for the hydride transfer reaction. The mechanism of 4-nitrophenol reduction has been established from supporting TEM studies. To further support our proposition, we have prepared a compositionally similar Cu2O–Cu–CuO nanocomposite using Cu2O and sodium borohydride which however displayed lower rate of reduction than that of the in situ produced ternary nanocomposite. The evolution of isolated Cu(0) nanoparticles for 4-nitrophenol reduction from Cu2O under surfactant-free condition has also been taken into consideration. The synthetic procedures of cuprous oxide as well as its catalytic activity in the reduction of 4-nitrophenol are very convenient, fast, cost-effective, and easily operable in aqueous medium and were followed spectrophotometrically. Additionally, the Cu2O-catalyzed 4-nitrophenol reduction methodology was extended further to the reduction of electronically diverse nitroarenes. This concise catalytic process in aqueous medium at room temperature revealed an unprecedented catalytic performance which would draw attention across the whole research community.

High-Performance Supercapacitor Electrode Based on Cobalt Oxide-Manganese Dioxide-Nickel Oxide Ternary 1D Hybrid Nanotubes.

Abstract: We report a facile method to design Co3O4–MnO2–NiO ternary hybrid 1D nanotube arrays for their application as active material for high-performance supercapacitor electrodes. This as-prepared novel supercapacitor electrode can store charge as high as ∼2020 C/g (equivalent specific capacitance ∼2525 F/g) for a potential window of 0.8 V and has long cycle stability (nearly 80% specific capacitance retains after successive 5700 charge/discharge cycles), significantly high Coulombic efficiency, and fast response time (∼0.17s). The remarkable electrochemical performance of this unique electrode material is the outcome of its enormous reaction platform provided by its special nanostructure morphology and conglomeration of the electrochemical properties of three highly redox active materials in a single unit.

NH3 gas sensor based on Pd/SnO2/RGO ternary composite operated at room-temperature

Abstract: Novel room-temperature NH3 gas sensors based on Pd, tin oxide (SnO2) and reduced graphene oxide (RGO) ternary nanocomposite (Pd/SnO2/RGO) film were fabricated by the one-pot route. The Pd/SnO2/RGO ternary nanocomposite films were characterized by Fourier transform infrared spectroscopy (FTIR), Raman, X-ray diffractometry (XRD), scanning electron microscopy (SEM) and atomic force microscopy (AFM). Microstructural observations revealed that the Pd and SnO2 nanoparticles easily and homogeneously attached to the surface of RGO. The sensor that was based on a Pd/SnO2/RGO ternary nanocomposite film responded strongly to low concentrations of NH3 gas at room-temperature. Its better sensor sensitivity than that of the pristine of SnO2 and SnO2/RGO nanocomposite film was related to the higher conductivity and catalytic activity of the Pd/SnO2/RGO ternary nanocomposite film.

How to explain microemulsions formed by solvent mixtures without conventional surfactants.

Abstract: Ternary solutions containing one hydrotrope (such as ethanol) and two immiscible fluids, both being soluble in the hydrotrope at any proportion, show unexpected solubilization power and allow strange but yet unexplained membrane enzyme activity. We study the system ethanol-water-octanol as a simple model of such kinds of ternary solutions. The stability of “detergentless” micelles or microemulsions in such mixtures was proposed in the pioneering works of Barden and coworkers [Smith GD, Donelan CE, Barden RE (1977) J Colloid Interface Sci 60(3):488–496 and Keiser BA, Varie D, Barden RE, Holt SL (1979) J Phys Chem 83(10):1276–1281] in the 1970s and then, neglected, because no general explanation for the observations was available. Recent direct microstructural evidence by light, X-ray, and neutron scattering using contrast variation reopened the debate. We propose here a general principle for solubilization without conventional surfactants: the balance between hydration force and entropy. This balance explains the stability of microemulsions in homogeneous ternary mixtures based on cosolvents.

Copper(I)-Based p-Type Oxides for Photoelectrochemical and Photovoltaic Solar Energy Conversion

Abstract: Recent research efforts have been growing into p-type copper(I) based oxides for development of their use in solar energy applications. The oxides of interest include the binary Cu2O and a number of new ternary CuxMyOz oxides. Both the binary and ternary Cu(I)-based oxides have many advantages when compared to other well-known p-type oxides such as NiO, III–V, and II–VI semiconductors. The benefits found within the diverse group of Cu(I)-containing oxides include bandgap sizes that can be tuned from ∼1.2 to >3.0 eV, high charge carrier mobility, and favorable band energies relative to fuel-producing redox couples. These properties give them potential utility in a variety of different solar applications, such as in dye-sensitized solar cells and suspended powder photocatalysis. Research efforts into surface modifications and changes in their chemical compositions and structures have allowed for greater stability and greater efficiency in aqueous solutions, both of which have represented two key barriers fo...

Highly Efficient Photocatalytic Hydrogen Evolution in Ternary Hybrid TiO2/CuO/Cu Thoroughly Mesoporous Nanofibers.

Abstract: Development of novel hybrid photocatalysts with high efficiency and durability for photocatalytic hydrogen generation is highly desired but still remains a grand challenge currently. In the present work, we reported the exploration of ternary hybrid TiO2/CuO/Cu thoroughly mesoporous nanofibers via a foaming-assisted electrospinning technique. It is found that by adjusting the Cu contents in the solutions, the unitary (TiO2), binary (TiO2/CuO, TiO2/Cu), and ternary (TiO2/CuO/Cu) mesoporous products can be obtained, enabling the growth of TiO2/CuO/Cu ternary hybrids in a tailored manner. The photocatalytic behavior of the as-synthesized products as well as P25 was evaluated in terms of their hydrogen evolution efficiency for the photodecomposition water under Xe lamp irradiation. The results showed that the ternary TiO2/CuO/Cu thoroughly mesoporous nanofibers exhibit a robust stability and the most efficient photocatalytic H2 evolution with the highest release rate of ∼851.3 μmol g–1 h–1, which was profound...

High-performance ternary blend all-polymer solar cells with complementary absorption bands from visible to near-infrared wavelengths

Abstract: We developed high-performance ternary blend all-polymer solar cells with complementary absorption bands from visible to near-infrared wavelengths. A power conversion efficiency of 6.7% was obtained with an external quantum efficiency over 60% both in the visible and near-infrared regions. Our results demonstrate that the ternary blend all-polymer systems open a new avenue for accelerating improvement in the efficiency of non-fullerene thin-film polymer solar cells.

Understanding Morphology Compatibility for High-Performance Ternary Organic Solar Cells

Abstract: Ternary organic solar cells are emerging as a promising strategy to enhance device power conversion efficiency by broadening the range of light absorption via the incorporation of additional light-absorbing components. However, how to find compatible materials that allow comparable loadings of each component remains a challenge. In this article, we focus on studying the donor polymer compatibilities in ternary systems from a morphological point of view. Four typical donor polymers with different chemical structures and absorption ranges were mutually combined to form six distinct ternary systems with fullerene derivative acceptors. Two compatible ternary systems were identified as showing significant improvements of efficiency from both binary control devices. Ternary morphologies were characterized by grazing incident X-ray scattering and correlated with device performance. We find that polymers that have strong lamellar interactions and relatively similar phase separation behaviors with the fullerene de...