Device Applications Research Articles

Unveiling Energy Conversion Mechanisms and Regulation Strategies in Perovskite Solar Cells.

Despite recent revolutionary advancements in photovoltaic (PV) technology, further improving cell efficiencies toward their Shockley-Queisser (SQ) limits remains challenging due to inherent optical, electrical, and thermal losses. Currently, most research focuses on improving optical and electrical performance through maximizing spectral utilization and suppressing carrier recombination losses, while there is a serious lack of effective opto-electro-thermal coupled management, which, however, is crucial for further improving PV performance and the practical application of PV devices. In this article, the energy conversion and loss processes of a PV device (with a specific focus on perovskite solar cells) are detailed under both steady-state and transient processes through rigorous opto-electro-thermal coupling simulation. By innovatively coupling multi-physical behaviors of photon management, carrier/ion transport, and thermodynamics, it meticulously quantifies and analyzes energy losses across optical, electrical, and thermal domains, identifies heat components amenable to regulation, and proposes specific regulatory means, evaluates their impact on device efficiency and operating temperature, offering valuable insights to advance PV technology for practical applications.

In situ Blending For Co-Deposition of Electron Transport and Perovskite Layers Enables Over 24% Efficiency Stable Inverted Solar Cells.

Simplifying the manufacturing processes of multilayered high-performance perovskite solar cells (PSCs) is yet of vital importance for their cost-effective production. Herein, an in situ blending strategy is presented for co-deposition of electron transport layer (ETL) and perovskite absorber by incorporating (3-(7-butyl-1,3,6,8-tetraoxo-3,6,7,8-tetrahydrobenzo- [lmn][3,8]phenanthrolin-2(1H)-yl)propyl)phosphonic acid (NDP) into the perovskite precursor solutions. The phosphonic acid-like anchoring group coupled with its large molecular size drives the migration of NDP toward indium tin oxide (ITO) surface to form a distinct ETL during perovskite film forming. This strategy circumvents the critical wetting issue and simultaneously improves the interfacial charge collection efficiencies. Consequently, n-i-p PSCs based on in situ blended NDP achieve a champion power conversion efficiency (PCE) of 24.01%, which is one of the highest values for PSCs using organic ETLs. This performance is notably higher than that of ETL-free (21.19%) and independently spin-coated (21.42%) counterparts. More encouragingly, the in situ blending strategy dramatically enhances the device stability under harsh conditions by retaining over 90% of initial efficiencies after 250h in 100°C or 65% humidity storage. Moreover, this strategy is universally adaptable to various perovskite compositions, device architectures, and electron transport materials (ETMs), showing great potential for applications in diverse optoelectronic devices.

Ultrafast Laser Manipulation of In-Lattice Plasmonic Nanoparticles.

Plasmonic nanoparticles enable manipulation and enhancement of light fields at deep subwavelength scales, leading to structures and devices for diverse applications in optics. Despite hybrid plasmonic materials display remarkable optical properties due to interactions between components in nanoproximity, scalable production of plasmonic nanostructures within a single-crystalline matrix to achieve an ideal plasmon-crystal interface remains challenging. Here, a novel approach is presented to realize efficient manipulation of in-lattice plasmonic nanoparticles. Employing ultrafast-laser-driven plasmonic nanolithography, metallic nanoparticles with controllable morphology are precisely defined in the crystalline lattice of yttrium aluminum garnet (YAG) crystal. Through direct ion implantation, hybrid plasmonic material composed of nanoparticles embedded in a sub-surface amorphous YAG layer is created. Subsequently, femtosecond laser pulses guide formation and reshaping of plasmonic nanoparticles from the amorphous layer into the single-crystalline matrix along direction of light propagation, facilitated by a plasmon-mediated evolution of laser energy deposition. By tailoring resonance modes and optimizing the coupling between structured particle assemblies, a range of applications including polarization-dependent absorption and nonlinearity, controllable photoluminescence, and structural color generation is demonstrated. This research introduces a new approach for fabricating advanced optical materials featuring in-lattice plasmonic nanostructures, paving the way for the development of diverse functional photonic devices.

Observation and enhancement of room temperature bilinear magnetoelectric resistance in sputtered topological semimetal Pt3Sn

Topological semimetal materials have attracted a great deal of attention due to their intrinsic strong spin-orbit coupling, which leads to large charge-to-spin conversion efficiency and novel spin transport behaviors. In this work, we have observed a bilinear magnetoelectric resistance (BMER) of up to 0.0034 nm2A−1Oe−1 in a single layer of sputtered semimetal Pt3Sn at room temperature. Being different from previous works, the value of BMER in sputtered Pt3Sn does not change out-of-plane due to the polycrystalline nature of the Pt3Sn layer. The observation of BMER provides strong evidence of the existence of spin-momentum locking in the sputtered polycrystalline Pt3Sn. By adding an adjacent CoFeB magnetic layer, the BMER value of this bilayer system is doubled compared to the single Pt3Sn layer. This work broadens the material system in BMER study, which paves the way for the characterization of topological states and applications for spin memory and logic devices.

Recent advances in vanadium dioxide for dynamic thermal radiation modulation: A review

Thermal radiation of materials can be manipulated for the necessary applications in thermal management and infrared camouflage. To our knowledge, controlling surface emissivity is crucial for modulating thermal radiative energy, therefore, dynamic modulation of emissivity has received more attention. Vanadium dioxide (VO2) stands out as a highly promising candidate due to its capacity for reversible transition from monoclinic VO2(M) to rutile VO2(R) near room temperature. This transition results in a rapid change from transparent to opaque within the mid-infrared spectrum accompanied by a reduction in emissivity. This review offers an overview of recent progresses in the dynamic control of thermal radiation of the surface by using VO2. It also summarizes the preparation, modulation mechanisms, and applications of positive and negative differential emissivity devices. Finally, the challenges and opportunities in advancing research on VO2-based smart devices are discussed.

The Horizons of Medical Mineralogy: Structure-Bioactivity Relationship and Biomedical Applications of Halloysite Nanoclay.

Medical mineralogy explores the interactions between natural minerals and living organisms such as cells, tissues, and organs and develops therapeutic and diagnostic applications in drug delivery, medical devices, and healthcare materials. Many minerals (especially clays) have been recognized for pharmacological activities and therapeutic potential. Halloysite clay (Chinese medicine name: Chishizhi), manifested as one-dimensional aluminum silicate nanotubes (halloysite nanotubes, HNTs), has gained applications in hemostasis, wound repair, gastrointestinal diseases, tissue engineering, detection and sensing, cosmetics, and daily chemicals formulations. Various biomedical applications of HNTs are derived from hollow tubular structures, high mechanical strength, good biocompatibility, bioactivity, and unique surface characteristics. This natural nanomaterial is safe, abundantly available, and may be processed with environmentally safe green chemistry methods. This review describes the structure and physicochemical properties of HNTs relative to bioactivity. We discuss surface area, porosity and surface defects, hydrophilicity, heterogeneity and charge of external and internal surfaces, as well as biosafety. The paper provides comprehensive guidance for the development of this tubule nanoclay and its advanced biomedical applications for clinical diagnosis and therapy.

Physical properties of InxSey and CuInSe2 thin films with potential application in radiation detectors

A study of InxSey and CuInSe2 thin films processed by the thermal co-evaporation technique by evaluating its physical properties is carried out. Both InxSey as well as CuInSe2 thin films were synthesized by multi-source thermal co-evaporation technique, using Knudsen-type effusion cells. The optical, structural, electrical, and morphological properties of each film were analyzed in order to determine the feasibility at the formation of a p-CuInSe2/n-InxSey heterojunction. InxSey films exhibited bandgap values in the range of 2.4–2.7 eV which was determined by UV–vis spectroscopic analysis. Vibrational modes associated to In2Se3 as well as Se are presented in the InxSey films according to Raman studies. The irregular morphology of the grains on the InxSey surface, with an average size of 380 nm are related to both In2Se3 and Se materials according to Raman spectroscopy and Scanning Electron Microscopy analysis. The InxSey thin films showed resistivity vales around 10–3 Ω·cm. The Hackee´s figure of Merit (FOMH) analysis supported the physical assumption that InxSey thin films are feasible to be used as window layer in a photovoltaic device because of the high values of FOMH obtained for samples processed at 300 °C. On the other hand, an influence on the morphology of the CuInSe2 films was observed when the films were synthetized at different substrate temperature. Uniform CuInSe2 films with agglomerated cauliflower-like grains with an average size of 1.8 μm were observed by SEM. The presence of binary phases within the CuInSe2 compound were detected through Raman and x-ray characterization. Average crystallite size of 61 nm and microstrain around 2.5 × 10–3 were estimated for the CuInSe2 films through x-ray analysis. According to the physical properties analyzed the InxSey/CuInSe2 semiconductor bilayer can be a suitable candidate for application in photovoltaic devices as well as charged particle detector.

Terahertz tunable three-dimensional photonic jets

Highly localized electromagnetic field distributions near the “shadow-side” surface of certain transparent mesoscale bodies illuminated by light waves are called photonic jets. We demonstrated formation of three-dimensional (3D) tunable photonic jets in terahertz regime (terajets, TJs) by dielectric micro-objects -including spheres, cylinders, and cubes-coated with a bulk Dirac semimetal (BDS) layer, under uniform beam illumination. The optical characteristics of the produced TJs can be modulated dynamically through tuning the BDS layer’s index of refraction via changing its Fermi energy. It is demonstrated that the Fermi energy of BDS layer has a significant impact on tuning the optical characteristics of the produced photonic jets for both TE and TM polarizations. A notable polarization dependency of the characteristics of the TJs was also observed. The impact of obliquity of the incident beam was studied as well and it was demonstrated that electromagnetic field distributions corresponding to asymmetric photonic jets can be formed in which the intensity at the focal region is preserved in a wide angular range which could find potential application in scanning devices. It was found that the maximum intensity of the TJ occurs at a non-trivial morphology-dependent source-angle.

Biocompatible Hybrid Graphenic Thin Coatings on Flexible Substrates through Matrix-Assisted Pulsed Laser Evaporation (MAPLE).

This work reports the production of biocompatible thin layers for biomedical applications based on a graphene-like material (GL), a graphene-related material (GRM) obtained from carbon black. GL was combined in a hybrid fashion with polydopamine (pDA), a mussel-inspired water-resistant wet adhesive bonding obtained by the oxidative polymerization of dopamine (DA), and polyvinyl pyrrolidinone (PVP), a nontoxic synthetic polymer with intrinsic adhesion properties, to obtain a tighter adhesion of the thin layer to the substrate (silicone slices). Matrix-assisted pulsed laser evaporation (MAPLE) was used to coat PDMS slices with thin films of GL-pDA and GL-PVP directly from their frozen suspensions in water. The results indicate that the relevant chemical-physical characteristics of both thin films (evidenced by FTIR and AFM) were maintained after MAPLE deposition and that the films exhibit uniformity also at the nanometric level. After deposition, the GL-pDA and GL-PVP films underwent a biological survey toward murine fibroblasts (NIH3T3), human keratinocytes (HaCAT), and human cervical adenocarcinoma epithelial-like (HeLa) cells to assess the feasibility of this approach. Results indicate that both the GL-pDA and GL-PVP films did not perturb the biological parameters evaluated, including cytoskeleton alterations. Both hybrid films enhanced the effects of GL on cellular vitality across all cell lines. Specifically, the GL-pDA film exhibited a more stable effect over time (up to 72 h), whereas the GL-PVP film behaved similarly to the GL film in NIH3T3 and HeLa cell lines after long-term exposure. These promising results make the GL-pDA and GL-PVP films potential candidates for the manufacture of coated flexible devices for biomedical applications.

Upgrading the production of plasma-activated water for sterilization by preloading long-lived reactive species

Plasma-activated water (PAW) has broad prospects in the medical field because it is rich in reactive nitrogen and oxygen species. However, in most production processes of PAW, a large proportion of gaseous reactive species is converted into long-lived aqueous species with minor biochemical activity, and only a small proportion is converted into crucial short-lived aqueous species, which results in inefficient activation of PAW. Given the indispensability and easy availability of long-lived aqueous species, this study proposes to preload HNO3 and H2O2 into water and then generate plasma to induce short-lived aqueous species, thus improving the production rate of PAW. The addition of 1 mM HNO3 and 0.5% H2O2 results in a 100-fold increase in the production rate of the PAW with a bactericidal rate exceeding 99.9999%, and the preloaded HNO3 and H2O2 promote the dissolution of O3 and the generation of short-lived aqueous species, respectively. Moreover, the preloaded species improve the validity period of PAW and the resistance of sterilization to acid-base neutralizers. This study offers a novel approach for upgrading the production of PAW, which holds promise for realizing rapid PAW production with a portable device for clinical medical applications.

Diamond/graphene (carbon sp3-sp2) heterojunctions for neuromorphic device applications

Diamond/graphene (carbon sp3-sp2) heterojunctions for neuromorphic device applications

First Principle insights on Optoelectronic, Mechanical, and Thermoelectric Properties of Double Perovskites Li2ScAu (Br/I)6 for Energy Harvesting Applications.

Abstract Li-based double perovskites (DPs) are extensively studied due to their potential applications for solar cells and thermoelectric devices. In the current paper, we explored the electronic, optical, transport, and mechanical aspects of Li2ScAu (Br/I)6 by density functional theory (DFT) based calculations. The tolerance factor and Born Criteria have been assumed for structural and mechanical stability. In contrast, energy and phonons band structures are examined for thermodynamic and dynamic (Lattice vibration) stability formation. The band gaps 1.96 eV and 1.42 eV for Li2ScAuBr6 and Li2ScAuI6 fall the absorption bands in the visible zone. The optical behavior in the energy range 0-5.0 eV has been addressed. Furthermore, low lattice thermal conductivity, large Seebeck coefficient, and electrical conductivity enhance the figure of merit (ZT) scale, increasing their importance for thermoelectric generators.

Organic Thermoelectric Materials for Wearable Electronic Devices

Wearable electronic devices have emerged as a pivotal technology in healthcare and artificial intelligence robots. Among the materials that are employed in wearable electronic devices, organic thermoelectric materials possess great application potential due to their advantages such as flexibility, easy processing ability, no working noise, being self-powered, applicable in a wide range of scenarios, etc. However, compared with classic conductive materials and inorganic thermoelectric materials, the research on organic thermoelectric materials is still insufficient. In order to improve our understanding of the potential of organic thermoelectric materials in wearable electronic devices, this paper reviews the types of organic thermoelectric materials and composites, their assembly strategies, and their potential applications in wearable electronic devices. This review aims to guide new researchers and offer strategic insights into wearable electronic device development.

Dual-quartet phosphorescent emission in the open-shell M1Ag13 (M = Pt, Pd) nanoclusters

Dual emission (DE) in nanoclusters (NCs) is considerably significant in the research and application of ratiometric sensing, bioimaging, and novel optoelectronic devices. Exploring the DE mechanism in open-shell NCs with doublet or quartet emissions remains challenging because synthesizing open-shell NCs is difficult due to their inherent instability. Here, we synthesize two dual-emissive M1Ag13(PFBT)6(TPP)7 (M = Pt, Pd; PFBT = pentafluorobenzenethiol; TPP = triphenylphosphine) NCs with a 7-electron open-shell configuration to reveal the DE mechanism. Both NCs comprise a crown-like M1Ag11 kernel with Pt or Pd in the center surrounded by five PPh3 ligands and two Ag(SR)3(PPh3) motifs. The combined experimental and theoretical studies revealed the origin of DE in Pt1Ag13 and Pd1Ag13. Specifically, the high-energy visible emission and the low-energy near-infrared emission arise from two distinct quartet excited states: the core-shell charge transfer and core-based states, respectively. Moreover, PFBT ligands are found to play an important role in the existence of DE, as its low-lying π* levels result in energetically accessible core-shell transitions. This novel report on the dual-quartet phosphorescent emission in NCs with an open-shell electronic configuration advances insights into the origin of dual-emissive NCs and promotes their potential application in magnetoluminescence and novel optoelectronic devices.

A Review of Research on RF MEMS for Metaverse Interactions

Abstract Metaverse as a comprehensive integration of multiple digital technologies of the new generation, enables human beings to bring unprecedented immersive experiences with the support of virtual reality, augmented reality, blockchain, digital twin, Artificial Intelligence, haptic IoT, and human-computer interaction. In view of the urgent need for high-speed and high-capacity data transmission as well as high integration, RF MEMS devices have become the core components for metaverse system building due to their advantages of miniaturization, high integration, and low power consumption. Playing a pivotal role in real-time high-capacity data transmission and signal processing in metaverse interactive systems, the low cost and high performance of RF MEMS devices have once again become the focus of attention for people from all walks of life. Therefore, this paper focuses on the working principles and performance optimization of RF MEMS devices. Firstly, the classification and basic principles of RF MEMS devices are introduced, followed by the advanced fabrication technology and optimization scheme of MEMS devices, and then the advanced applications of RF MEMS devices in the field of metaverse are discussed in focus, including IoT mobile communication, Artificial Intelligence, and flexible wearables. Finally, the prospects and potential challenges for the development of RF MEMS devices interacting with the metaverse are summarized and discussed.

First-principles predictions of HfO2-based ferroelectric superlattices

The metastable nature of the ferroelectric phase of HfO2 is a significant impediment to its industrial application as a functional ferroelectric material. In fact, no polar phases exist in the bulk phase diagram of HfO2, which shows a dominant non-polar monoclinic ground state. As a consequence, ferroelectric orthorhombic HfO2 is stabilized either kinetically or via epitaxial strain. Here, we propose an alternative approach, demonstrating the feasibility of thermodynamically stabilizing polar HfO2 in superlattices with other simple oxides. Using the composition and stacking direction of the superlattice as design parameters, we obtain heterostructures that can be fully polar, fully antipolar or mixed, with improved thermodynamic stability compared to the orthorhombic polar HfO2 in bulk form. Our results suggest that combining HfO2 with an oxide that does not have a monoclinic ground state generally drives the superlattice away from this non-polar phase, favoring the stability of the ferroelectric structures that minimize the elastic and electrostatic penalties. As such, these diverse and tunable superlattices hold promise for various applications in thin-film ferroelectric devices

Operational stability study of lactate biosensors: modeling, parameter identification, and stability analysis

IntroductionThis paper investigates the operational stability of lactate biosensors, crucial devices in various biomedical and biotechnological applications. We detail the construction of an amperometric transducer tailored for lactate measurement and outline the experimental setup used for empirical validation.MethodsThe modeling framework incorporates Brown and Michaelis–Menten kinetics, integrating both distributed and discrete delays to capture the intricate dynamics of lactate sensing. To ascertain model parameters, we propose a nonlinear optimization method, leveraging initial approximations from the Brown model’s delay values for the subsequent model with discrete delays.ResultsStability analysis forms a cornerstone of our investigation, centering on linearization around equilibrium states and scrutinizing the real parts of quasi-polynomials. Notably, our findings reveal that the discrete delay model manifests marginal stability, occupying a delicate balance between asymptotic stability and instability. We introduce criteria for verifying marginal stability based on characteristic quasi-polynomial roots, offering practical insights into system behavior.DiscussionQalitative examination of the model elucidates the influence of delay on dynamic behavior. We observe a transition from stable focus to limit cycle and period-doubling phenomena with increasing delay values, as evidenced by phase plots and bifurcation diagrams employing Poincaré sections. Additionally, we identify limitations in model applicability, notably the loss of solution positivity with growing delays, underscoring the necessity for cautious interpretation when employing delayed exponential function formulations. This comprehensive study provides valuable insights into the design and operational characteristics of lactate biosensors, offering a robust framework for understanding and optimizing their performance in diverse settings.

Coatable strain sensors for nonplanar surfaces.

Rapidly fabricating flexible and stretchable sensors on nonplanar surfaces is crucial for wearable device applications. We employed a novel fabrication method, incorporating molds and gels into electroless plating, to enable direct printing of sensors on a wide array of surfaces, from those with up to 100 μm profile heights to hydrogels with a Young's modulus of 100 kPa. This coatable strain (CS) sensor offers several potential advantages. Firstly, it is designed to circumvent the typical limitations of limited flexibility, plastic deformation, and low repeatability found in viscoelastic polymers by being directly coated onto the surface without requiring a substrate. Secondly, it potentially increases the effective contact area and signal-to-noise ratio by eliminating voids between the sensor and the surface. Finally, the CS sensor can obtain any desired patterning at room temperature in a matter of minutes, significantly reducing energy and time consumption. In this study, we demonstrated the versatility of the CS sensor by applying it to a range of substrates, showcasing its adaptability to diverse materials, surface roughness levels, and Young's modulus values. Our primary focus was on plant growth monitoring, a challenging application that showcased the sensor's efficacy on surfaces like needles, hairy leaves, and fruits. These applications, traditionally difficult for conventional polymer-based sensors, serve to illustrate the CS sensor's potential in a range of complex environmental contexts. The successful deployment of the CS sensor in these settings suggests its broader applicability in various scientific and technological fields, potentially contributing to significant developments in the area of wearable devices and beyond.

Study of Thermodynamic, Optoelectronic and Thermoelectric Properties of BaSiO3 Crystals Doped With Er3+ and Yb3+ for Energy Renewable Devices Applications

Study of Thermodynamic, Optoelectronic and Thermoelectric Properties of BaSiO3 Crystals Doped With Er3+ and Yb3+ for Energy Renewable Devices Applications

Friction Force Mapping of Molecular Ordering and Mesoscopic Phase Transformations in Layered-Crystalline Organic Semiconductor Films.

It is critical to understand molecular ordering processes in small-molecule organic semiconductor (OSC) films in optimizing electronic device applications, although it is difficult to observe and investigate the ordering characteristics at a mesoscopic or device scale. Here, we report that friction force microscopy (FFM) allows visualizing the ordering transformation process from a thermodynamically metastable phase to a stable phase at a mesoscopic scale. We utilized 2-octyl-benzothieno[3,2-b]naphtho[2,3-b]thiophene (2-C8-BTNT) as a typical highly layered-crystalline OSC. We found that the friction force between an AFM tip and spin-coated OSC films significantly depends on whether local film states are in metastable monolayer phase or stable bilayer-type herringbone (b-LHB) phase that exhibits high carrier mobility. The formation of the stable b-LHB phase leads to lower friction than the metastable monolayer phase, clearly visualizing the molecular order. Force map (Fmap) analysis indicates that the lower friction in the b-LHB phase should be associated with the reduction of interfacial adhesion force. Notably, the observed results demonstrate that the spin-coated thin film changes from continuous film with the monolayer phase to rugged microcrystal grains with the b-LHB phase when left at ambient conditions. By contrast, an appropriate post-thermal annealing process facilitates the phase transformation without inducing such morphological changes. The technique provides a unique and effective tool for revealing the relationship between processing conditions and device performance in polycrystalline OSC films.