Planar Architecture Research Articles

Metalloporphyrin-anchored 2D MOF nanosheets as highly accessible heterogeneous photocatalysts towards cytocompatible living radical polymerization

Two-dimensional (2D) metal–organic framework (MOF) nanosheets have emerged as a promising hybrid material due to the highly exposed active sites and high aspect ratio originating from their large lateral dimension and ultrathin thickness. Herein, PCN-134(Zn)-2D (PCN = porous coordination network) nanosheets were investigated as a versatile and effective platform supporting metalloporphyrins to boost their photocatalytic performance for single oxygen generation and living radical polymerization. This method enabled the radical polymerizations of various monomers using low catalyst dosages under a wide range of wavelengths, affording well-defined polymers with high monomer conversions, low polydispersities and tunable functionalities. Compared to three-dimensional (3D) bulk MOF crystals, PCN-134(Zn)-2D exhibited fast polymerization kinetics due to the larger surface area and more accessible catalytic sites within the 2D planar architecture. Most significantly, the polymerization kinetics could be orthogonally regulated by solution pH and light stimuli. Exploiting the oxygen tolerance and fast kinetics, we demonstrated PET-RAFT polymerization at high monomer dilutions and in a human cell culture medium. Illustrations of chain extension and catalyst-recycling test further substantiated the photocatalytic performance of these 2D MOF catalysts outperforming most reported metalloporphyrin-based heterogeneous catalysts towards living radical polymerization.

CuSCN as a hole transport layer in an inorganic solution-processed planar Sb2S3solar cell, enabling carbon-based and semitransparent photovoltaics

CuSCN as HTL is used in inorganic planar carbon electrode-based Sb2S3solar cells resulting in a higher PCE (1.95%) compared to Au (PCE = 1.75%). Also, this planar device architecture enables a semitransparent solar cell (PCE = 1.67%, AVT = 27.6%).

Tunable coupling scheme for implementing two-qubit gates on fluxonium qubits

A superconducting fluxonium circuit is an RF-superconducting quantum interference device-type flux qubit that uses a large inductance built from an array of Josephson junctions or a high kinetic inductance material. This inductance suppresses charge sensitivity exponentially and flux sensitivity quadratically. In contrast to the transmon qubit, the anharmonicity of fluxonium can be large and positive, allowing for better separation between the low energy qubit manifold of the circuit and higher-lying excited states. Here, we propose a tunable coupling scheme for implementing two-qubit gates on fixed-frequency fluxonium qubits, biased at half flux quantum. In this system, both qubits and couplers are coupled capacitively and implemented as fluxonium circuits with an additional harmonic mode. We investigate the performance of the scheme by simulating a universal two-qubit fSim gate. In the proposed approach, we rely on a planar on-chip architecture for the whole device. Our design is compatible with existing hardware for transmon-based devices with the additional advantage of lower qubit frequency facilitating high-precision gating.

Textured HTM-free perovskite/PbS quantum dot solar cell: Optical and electrical efficiency improvement by light trapping control

In recent years, have been seen a leap at the opportunity of investigation tandem solar cells. This due to the complementary bandgap energies of various layers which leads to enhancement of the light absorption and the power conversion efficiency (PCE) of this type of solar cells. In this numerical based study, a new hole transport material (HTM) free perovskite/quantum dot solar cell, exploiting a finite element method (FEM), has been conducted for the first time. The series connection of perovskite (CH3NH3PbI3, 1.55 eV) and colloidal quantum dot (CQD) of lead sulphide (PbS-CQD, 1.3 eV) as light-carrier absorber layers is analysed to achieve the optimal performance with short-circuit current (Jsc) = 25.4 mA/cm2, open-circuit voltage (Voc) = 0.8 V, fill factor (FF) = 0.84. The simulation results illustrate that tandem solar cell yields an overall PCE of 17.2%, exceeding that of 14.53 % of bare perovskite absorbing layer in planar perovskite solar cell (PSC). To enhance the light absorption within the absorber layer and consequently to achieve a higher efficiency, pyramidal texturing of layers, as an effective light-management method was investigated and it reveals that the Jsc and PCE is increased to 29.3 mA/cm2 and 19.52% respectively. Comparing to the planar perovskite architecture, PCE is improved from 14.53% to 19.52%, indicating a great potential of nanostructure designing in tandem solar cells.

A Simulation Study of a Planar Cable-Driven Parallel Robot to Transport Supplies for Patients with Contagious Diseases in Health Care Centers

Currently, a large number of investigations are being carried out in the area of robotics focused on proposing solutions in the field of health, and many of them have directed their efforts on issues related to the health emergency due to COVID-19. Considering that one of the ways to reduce the risk of contagion is by avoiding contact and closeness between people when exchanging supplies such as food, medicine, clothing, etc., this work proposes the use of a planar cable-driven parallel robot for the transport of supplies in hospitals whose room distribution has planar architecture. The robot acts in accordance with a procedure proposed for each task to be carried out, which includes the process of disinfection (based on Ultraviolet-C light) of the supplies transported inside the robot’s end effector. The study presents a design proposal for the geometry of the planar cable-driven parallel robots and its end effector, as well as the software simulations that allow evaluating the robot’s movement trajectories and the responses of the position control system based on Fuzzy-PID controllers.

Rational Cathode Design for High‐Power Sodium‐Metal Chloride Batteries

AbstractThe transition from fossil fuels to renewable energy sources requires economic, high‐performance electrochemical energy storage. High‐temperature sodium‐metal chloride batteries combine long cycle and calendar life, with high specific energy, no self‐discharge, and minimum maintenance requirements, while employing abundant raw materials. However, large‐scale deployment in mobility and stationary storage applications is currently hindered by high production cost of the complex, commercial tubular cells and limited rate capability. The present study introduces sodium‐metal chloride cells with a simple, planar architecture that provide high specific power while maintaining the inherent high specific energy. Rational cathode design, considering critical transport processes and the effect of cathode composition on the cell resistance, enables the development of high‐performance cells with average discharge power of 1022 W kg−1 and discharge energy per cycle of 258 Wh kg−1 on cathode composite level, shown over 140 cycles at an areal capacity of 50 mAh cm−2. This corresponds to a 3.2C discharge over 80% of full charge. Compared to the best performing planar sodium‐metal chloride cells with similar cycling stability and mass loading in the literature, the presented performance represents an increase in specific power by more than a factor of four, while also raising the specific energy by 74%.

Low-temperature treated anatase TiO2 nanophotonic-structured contact design for efficient triple-cation perovskite solar cells

We report on the preparation and optimization of low temperature (<200 °C) processed TiO2 film as an electron transport layer (ETL) for high-performance perovskite solar cells (PSCs) compatible with flexible substrates. A high-quality ETL is spin-coated from hydrothermal synthesized single-phase crystalline anatase TiO2 nanoparticles (NPs) with an average diameter of 6 ~ 10 nm. The surface of the high crystallite TiO2 NPs reveals a tendency toward interparticle necking, facilitating compact scaffolds, resulting in PSCs with high power conversion efficiencies (PCEs). The influence of low and high temperature treated TiO2 ETL on the device performance is studied. The best planar device fabricated in superstrate configuration (sup-C) exhibits a PCE of 17.1% with a JSC of 20.3 mA/cm2. The PCE can be increased by ~ 25%, up to 23%, by moving from planar architecture in sup-C to the textured solar cell in substrate configuration (sub-C). The PSC covered with a nanophotonic-structured front contact allows gaining 8% and 15% on VOC and JSC, respectively, where 2/3 of JSC gain is attributed to improved light incoupling, while the remaining 1/3 is due to increased diffraction at long wavelengths. The optical and electrical characteristics of the devices are investigated by 3D finite-domain time-domain (FDTD) and finite element method (FEM) rigorous simulations. Detailed guidelines on the nanophotonic design are provided.

Reconstructive spectrometer using a photonic crystal cavity.

Optical spectrometers have propelled scientific and technological advancements in a wide range of fields. While sophisticated systems with excellent performance metrics are serving well in controlled laboratory environments, many applications require systems that are portable, economical, and robust to optical misalignment. Here, we propose and demonstrate a spectrometer that uses a planar one-dimensional photonic crystal cavity as a dispersive element and a reconstructive computational algorithm to extract spectral information from spatial patterns. The simple fabrication and planar architecture of the photonic crystal cavity render our spectrometry platform economical and robust to optical misalignment. The reconstructive algorithm allows miniaturization and portability. The intensity transmitted by the photonic crystal cavity has a wavelength-dependent spatial profile. We generate the spatial transmittance function of the system using finite-difference time-domain method and also estimate the dispersion relation. The transmittance function serves as a transfer function in our reconstructive algorithm. We show accurate estimation of various kinds of input spectra. We also show that the spectral resolution of the system depends on the cavity linewidth that can be improved by increasing the number of periodic layers in distributed Bragg mirrors. Finally, we experimentally estimate the center wavelength and linewidth of the spectrum of an unknown light emitting diode. The estimated values are in good agreement with the values measured using a commercial spectrometer.

3D-printed twisted yarn-type Li-ion battery towards smart fabrics

Flexible batteries have gained significant attention in recent years, owing to their huge demand for portable wearable electronics and smart fabrics. However, conventional Li-ion batteries (LIBs) have limited device adaptability because of their planar architecture. To address this issue, the LIBs are shrunk to a one-dimensional fiber shape, which provides the freedom and flexibility needed for their integration with wearable electronics and smart fabrics. Herein, we demonstrate a method to fabricate twisted yarn-type (TYT) LIBs by a direct ink writing-based three-dimensional printing technology, using natural graphite and LiNi0.6Co0.2Mn0.2O2 as anode and cathode active materials, respectively, along with vapor-grown carbon fibers as an integrated conductive matrix. The printed electrode fibers are twisted together to create anode and cathode yarns, which are then assembled together to obtain a prototype TYT LIB device. The fabricated device performs significantly better in terms of both electrochemical performance and flexibility. The proposed method thus enables the direct integration of batteries into commercial fabrics either in the form of individual electrodes or full devices, which opens up a new route for developing next-generation energy storage devices for smart fabrics.

Humidity-resistant perovskite solar cells via the incorporation of halogenated graphene particles

One of the main challenges facing large-scale commercialization of perovskite solar cells (PSCs) is their stability and susceptibility to humidity. Herein, a rapid single-step laser treatment process is employed to fabricate highly hydrophobic, halogenated graphene particles. These particles are integrated into a planar cesium formamidinium lead iodide PSC architecture as an additive in the spiro-OMeTAD hole-transporting layer or as a capping layer on the spiro-OMeTAD. The graphene particles functionalized with chlorine and iodine were found to significantly enhance the stability of the PSCs in both ambient and highly humid conditions. Notably, inclusion of graphene particles functionalized with both iodine and chlorine resulted in the absorbance of an unencapsulated perovskite device decaying by only 18% over a 6000 hr testing span in ambient conditions. When the halogenated graphene particles were incorporated as an additive in the spiro-OMeTAD, the power conversion efficiency was also improved, which was attributed to improved hole extraction by the halogenated graphene particles, as observed by steady-state and time-resolved photoluminescence.

Tubular ring thermoelectric module for exhaust pipes: From Skutterudite nanopowders to the final device

There is an important number of thermoelectric applications in the range of medium temperatures (between 200 and 600 °C), such as heat recovery in automotive applications, where these temperatures are easily reached in the exhaust or the motor. Among the various materials which exhibit good thermoelectric properties in this range, Skutterudites (with the general formula CoSb3) stand out as some of the most used. In recent years, different improvements have been done to decrease their thermal conductivity, from using rattler atoms inside their structure to nanostructuring by sintering nanoparticles and increasing the number of grain boundaries. In this work, we present the subsequent development of the nanopowder ball-milling fabrication method, to obtain a scalable production of n-type and p-type nanostructured Skutterudites. The sintering of these powders into nano-composites was done by different pressing and annealing treatments, which not only could substitute other sintering processes such as Spark Plasma Sintering, giving competitive values of the thermoelectric properties of the final nanostructured material, but can also be used to directly obtain different geometries to be used in certain implementations. This procedure has been tested by fabricating thermoelectric legs of the thermoelectric nanostructured material in the shape of rings, in contrast with the more generally available thermoelectric modules, which have a planar architecture. The ring-shaped architecture was obtained by pressing the nano-powders between copper rings, and from them, cylindrical thermoelectric generators were implemented, which present several of advantages for their use in automotive waste heat recovery from the exhaust, for instance. The optimal parameters, as far as geometry and the materials used in the final device, can be extracted from simulations based on the actual measurements obtained in the fabricated thermoelectric rings. Taking all these into account, in this work we present a route to fabricate low-cost nano-structured Skutterudite in an easily scalable way, suitable for the implementation of different architectures of thermoelectric generators for mid-range temperature applications.

Composition engineering of operationally stable CsPbI2Br perovskite solar cells with a record efficiency over 17%

Despite the rapid progress in inorganic cesium lead halide perovskite (CsPbX 3 ) materials originating from excellent thermal stability; their poor phase stability at room temperature and lower efficiency compared to organic-inorganic counterparts still limit their development toward commercialization. Recently, Pb-site doping of inorganic perovskites stand outs for the improvement of aforementioned issues for emerging photovoltaic applications. Herein, we introduce a compositional engineering approach to tune the CsPbI 2 Br crystallization by directly incorporating iron (II) chloride (FeCl 2 ) into perovskite precursor. The small amount of FeCl 2 stabilizes the black α-phase to avoid the undesirable formation of the non-perovskite phase owing to Fe 2+ induced grain size reduction. Besides, the FeCl 2 incorporation thoroughly align the energy level, promote the built-in potential ( V bi ), and reduce the defect states in the perovskite, resulting in a record power conversion efficiency (PCE) of 17.1% with a remarkable open-circuit voltage ( V OC ) of 1.31 V. More importantly, FeCl 2 -doped CsPbI 2 Br-based devices exhibit an exceptional operational stability with a retention of over 95% initial PCE after 330 h at maximum power point (MPP) tracking. • A compositional engineering approach based on iron (II) chloride (FeCl 2 ) stabilizes the photoactive α-phase. • FeCl 2 incorporation thoroughly align the energy level, promote the built-in potential, and reduce the defect states. • A record efficiency of 17.1% was thoroughly achieved in a planar architecture with a remarkable open-circuit voltage ( V OC ) of 1.31 V. • FeCl 2 -doped CsPbI 2 Br-based devices exhibit an exceptional operational stability with a retention of over 95% after 330 h.

Research Progress of Multifunctional Metasurfaces Based on the Multiplexing Concept

As a two-dimensional metamaterial equivalent, the gradient metasurface has become a focus of intense research hotspot since it exhibits powerful ability in manipulating electromagnetic waves due to its planar architecture, flexible selection between anisotropic and isotropic structures, and its abrupt discontinues phase. Here, we first reviewed recent research progress in multifunctional metasurfaces based on the multiplexing concept from a new perspective of combining one, two and even more degrees of freedom of polarization, frequency, incident angles and directions (excitation information), and output-wave position information. Therein, we achieve a clear outline of a research program and technical approach to multifunctional metasurfaces. Second, we predict future routes of development of multifunctional metasurfaces, aiming to afford novel avenues to the realization of more sophisticated and larger-capacity integrated wavefront control and multifunctional devices with new physics, which are promising for highly-integrated and miniaturized future communication and radar devices.

Crystal Engineering Approach for Fabrication of Inverted Perovskite Solar Cell in Ambient Conditions

In this paper, we demonstrate the high potentialities of pristine single-cation and mixed cation/anion perovskite solar cells (PSC) fabricated by sequential method deposition in p-i-n planar architecture (ITO/NiOX/Perovskite/PCBM/BCP/Ag) in ambient conditions. We applied the crystal engineering approach for perovskite deposition to control the quality and crystallinity of the light-harvesting film. The formation of a full converted and uniform perovskite absorber layer from poriferous pre-film on a planar hole transporting layer (HTL) is one of the crucial factors for the fabrication of high-performance PSCs. We show that the in-air sequential deposited MAPbI3-based PSCs on planar nickel oxide (NiOX) permitted to obtain a Power Conversion Efficiency (PCE) exceeding 14% while the (FA,MA,Cs)Pb(I,Br)3-based PSC achieved 15.6%. In this paper we also compared the influence of transporting layers on the cell performance by testing material depositions quantity and thickness (for hole transporting layer), and conditions of deposition processes (for electron transporting layer). Moreover, we optimized second step of perovskite deposition by varying the dipping time of substrates into the MA(I,Br) solution. We have shown that the layer by layer deposition of the NiOx is the key point to improve the efficiency for inverted perovskite solar cell out of glove-box using sequential deposition method, increasing the relative efficiency of +26% with respect to reference cells.

GABr Post-Treatment for High-Performance MAPbI3 Solar Cells on Rigid Glass and Flexible Substrate.

Perovskite solar cells have exhibited astonishing photoelectric conversion efficiency and have shown a promising future owing to the tunable content and outstanding optoelectrical property of hybrid perovskite. However, the devices with planar architecture still suffer from huge Voc loss and severe hysteresis effect. In this research, Guanidine hydrobromide (GABr) post-treatment is carried out to enhance the performance of MAPbI3 n-i-p planar perovskite solar cells. The detailed characterization of perovskite suggests that GABr post-treatment results in a smoother absorber layer, an obvious reduction of trap states and optimized energy level alignment. By utilizing GABr post-treatment, the Voc loss is reduced, and the hysteresis effect is alleviated effectively in MAPbI3 solar cells. As a result, solar cells based on glass substrate with efficiency exceeding 20%, Voc of 1.13 V and significantly mitigated hysteresis are fabricated successfully. Significantly, we also demonstrate the effectiveness of GABr post-treatment in flexible device, whose efficiency is enhanced from 15.77% to 17.57% mainly due to the elimination of Voc loss.

Impact of precursor concentration on the properties of perovskite solar cells obtained from the dehydrated lead acetate precursors

In this research, we examined the impact of solution concentration on the photovoltaic and the material properties of perovskite solar cells (PSCs) obtained from dehydrated Pb-acetate precursors. The perovskite solution was deposited by a one-step spin-coating technique followed by 5 min of thermal annealing on a hotplate at the temperature of 90 °C to form the perovskite active layer. The PSC device structure adopted was the inverted planar architecture. The precursor solution concentrations were varied from 0.7 to 1.1M, with the optimal solution concentration found to be 1.0M. This concentration results in a power conversion efficiency of 12.2%, an open circuit voltage (Voc) of 0.94 V, a short circuit photocurrent density (Jsc) of 20.71 mA/cm2, and a fill factor of 62.69%. Our investigations revealed that the precursor solution concentration had a huge effect on the quality of the perovskite film and the photovoltaic properties of the PSCs.

Impact of Terrestrial Neutrons on the Reliability of SiC VD-MOSFET Technologies

Accelerated terrestrial neutron irradiations were performed on different commercial SiC power MOSFETs with planar, trench, and double-trench architectures. The results were used to calculate the failure cross sections and the failure-in-time (FIT) rates at sea level. Enhanced gate and drain leakage were observed in some devices which did not exhibit a destructive failure during the exposure. In particular, a different mechanism was observed for planar and trench gate MOSFETs, the first showing a partial gate rupture with a leakage path mostly between the drain and the gate, similar to what was previously observed with heavy ions, while the second exhibiting a complete gate rupture. The observed failure mechanisms and the postirradiation gate stress (PIGS) tests are discussed for different technologies.

Complementary interface formation toward high-efficiency all-back-contact perovskite solar cells

Summary All-back-contact (ABC) architectures for perovskite photovoltaics represent untapped potential for higher efficiency and enhanced durability compared to conventional planar architectures. Interface engineering can be more complex in ABC designs, because both the electron and hole transport layers (ETLs/HTLs) are simultaneously exposed during processing. Herein, we fabricate ABC perovskite solar cells with a non-stabilized current-voltage scan power conversion efficiency >10% by developing complementary interface processing. UV-ozone exposure followed by annealing increases the work function and reduces the defect density of the NiOx HTL and removed contamination from the TiO2 ETL, which increases voltage and current collection. We measure the chemical composition of each transport layer interface using photoelectron spectroscopy and then use the resulting trends to inform a two-dimensional drift-diffusion model. The model suggests that further reduction of charged interface defect density, increase in the hole selective contact work function, and passivation of the front surface will enable >20% of ABC devices.

A Dynamically Balanced Kinematically Redundant Planar Parallel Robot

AbstractA dynamically balanced robotic manipulator does not exert forces or moments onto the base on which it is fixed; this can be important for the performance of parallel robots as they are able to move at very high speeds, albeit usually have a reduced workspace. In recent years, kinematically redundant architectures have been proposed to mitigate the workspace limitations of parallel manipulators and increase their rotational capabilities; however, dynamically balanced versions of these architectures have not yet been presented. In this paper, a dynamically balanced kinematically redundant planar parallel architecture is introduced. The manipulator is composed of parallelogram linkages that reduce the number of counter rotary elements required to moment balance the mechanism. The balancing conditions are derived, and the balancing parameters are optimized using Lagrange multipliers, such that the total mass and inertia of the system is minimized. The elimination of the shaking forces and moments is then verified via a simulation in the multi-body dynamic simulation software msc adams.

Three-dimensional geometry and growth of a basement-involved fault network developed during multiphase extension, Enderby Terrace, North West Shelf of Australia

Abstract Basement fault reactivation, and the growth, interaction, and linkage with new fault segments are fundamentally three-dimensional and critical for understanding the evolution of fault network development in sedimentary basins. This paper analyzes the evolution of a complex, basement-involved extensional fault network on the Enderby Terrace on the eastern margin of the Dampier sub-basin, North West Shelf of Australia. A high-resolution, depth-converted, 3-D seismic reflection data volume is used to show that multiphase, oblique extensional reactivation of basement-involved faults controlled the development of the fault network in the overlying strata. Reactivation of the pre-existing faults initially led to the formation of overlying, en échelon Late Triassic–Middle Jurassic fault segments that, as WNW-directed rifting progressed on the margin, linked by breaching of relay zones to form two intersecting fault systems (F1 and F2–F4). Further reactivation in the latest Jurassic–Early Cretaceous (NNW-SSE extension) produced an additional set of en échelon fault arrays in the cover strata. The final fault network consists of main or principal faults and subordinate or splay faults, together with branch lines that link the various components. Our study shows that breaching of relay ramps and/or vertical linkages produces vertical and horizontal branch lines giving complex final fault geometries. We find that repeated activity of the basement-involved faults tends to form continuous and planar fault architectures that favor displacement transfer between the main constituent segments along strike and with depth.