Low-cost Manufacturing Research Articles

High-speed, low-voltage, low-bit-energy silicon photonic crystal slow-light modulator with impedance-engineered distributed electrodes

Silicon modulators in optical transceivers feature high-density integration and low manufacturing cost, but they also need to deliver high speed and low power consumption to meet the demands of future data centers and high-performance computing. This paper demonstrates a significantly improved 64 Gbps silicon Mach–Zehnder modulator incorporating photonic crystal slow-light phase shifters. By employing distributed electrodes and engineering their impedance, electro-optic phase matching and electrical impedance matching were obtained simultaneously, and the driving voltage was reduced to 0.87 V, which is compatible with fin-type field effect transistors and eliminates the need for additional electrical amplifiers. The bit energy of as low as 59 fJ/bit is comparable to that of microring modulators, while this modulator does not require temperature control like that used for microring modulators, due to its wide working spectrum of 6 nm. These results indicate the potential for addressing power issues in next-generation data infrastructures.

Solution-processed ZnO quantum dot thin films with low solvent residues and ultra-flat surfaces

ZnO quantum dots are considered a desirable material for the electron transport layer (ETL) in thin-film optoelectronic devices, determining their efficiency and stability. Solution-processed ZnO quantum dot films are fascinating due to the potential for low-cost manufacture of large-area devices and the compatibility with flexible substrates. However, eliminating solvent residues from solution-derived ZnO films remains a challenge, as their presence can significantly impact the efficiency and performance of the devices. Herein, we reported a straightforward and controllable strategy to overcome the above problem, aiming to achieve low solvent residues and ultra-flat ZnO films. Methanol, with its low boiling point and high relative evaporation rate, is utilized as a dispersing solvent for ZnO quantum dots, the resulting thin films exhibit low solvent residue, as confirmed by TGA and NMR analyses. Moreover, we achieved a stable monodisperse state of ZnO quantum dots in methanol solvent for three months by a simple temperature control method. The ZnO film prepared using a low-temperature spin-coating technique demonstrates extremely low surface roughness (RMS less than 1 nm).

Review on Mathematical Modelling of Boomerang for Novel Outfield Applications

A boomerang is an aerodynamically built object that, when thrown precisely, makes a quasi-circular flight and returns closely to its starting position. Numerous academics have analysed the boomerangs' motion and aerodynamics. None of the researchers in the field investigated the possibility of using the boomerangs for novel field applications rather than hunting and playing. Using boomerangs for field applications is beneficial in several ways because, unlike general drones, these boomerangs do not consume power continuously and low manufacturing cost. Using a boomerang in outfield applications is challenging because the external field is always unsteady and turbulent; therefore, a boomerang should be mathematically modelled for unsteady environment for precisely predict the trajectory. Few steady mathematical models were developed and validated in the reported literature and an unsteady mathematical model of boomerang was developed recently though it was not experimentally validated. The article reviews the mathematical modelling of boomerangs for certain novel outfield applications like agricultural inspection and weather monitoring. The depth of study in the mathematical modelling of boomerang is insufficient for developing novel applications. The article will aid the industrialists and researchers to advance in the field, and they can see the possibility of replacing the drones in novel outfield applications.

The design of chemisorption and catalysis synergistic defender for efficient room temperature sodium-sulfur batteries

Room temperature sodium-sulfur (RT-Na/S) batteries are a promising candidate for large-scale energy storage systems owing to their low manufacturing cost and high energy density. However, the severe shuttle effects and sluggish reaction kinetics hinder their practical application. Here, a Fe3Se4 nanoparticle anchored three-dimensional nitrogen-doped porous carbon nanosheet was designed as a functional defender to inhibit the shuttle effect and achieve high sulfur utilization. The porous carbon nanosheet builds a fast platform for electron and ion transport and acts as a limiting barrier for polysulfide dissolution and shuttling. Additionally, Fe3Se4 nanoparticles are incorporated to enhance the chemical anchoring and catalytic activity of polysulfides. The ex-situ characterization revealed that the Fe sites can feed electrons to polysulfides, thus facilitating the conversion of long-chain polysulfides to Na2S, resulting in high sulfur availability (323 mAh/g at 2 A/g) and long-term cycle life (72 % capacity retention at 1 A/g for 500 cycles).

Wide scan angle multibeam conformal antenna array with novel feeding for mm-wave 5G applications

This paper presents a low-profile wide scan angle multibeam conformal antenna array system with a novel feeding network for 28 GHz mm-wave 5G applications. The proposed antenna system utilizes two conventional branch-line couplers as its beamforming network. A novel feeding technique is applied to generate 7 beams with these couplers that are usually capable of generating 2 beams. The proposed solution provides a wide scanning range with a minimum realized gain of 5 dBi from −90° to 90° owing to this feeding approach and the peculiar placement of the array elements on a 0.15 mm thick R-F775 bendable substrate. The generated beams at their steer direction have the minimum and maximum gain values of 6.5 dBi and 9.7 dBi, respectively. A low-cost PCB manufacturing technique based on soft lithography and wet etching is used. The system dimensions excluding extra connector sections are 67×15×3mm3. The proposed flexible design is suitable for lightweight 5G communication systems and handsets with its compact low-complexity beamforming network, and wide 180° continuous covering angle.

Fluorine substitution for aggregation transformation and exciton dissociation acceleration in non-fused electron acceptors

In order to enable low-cost manufacture of organic solar cells (OSCs), it is very important to develop non-fused electron acceptors to match with one of the cheapest polymer donors, poly(3-hexylthiophene) (P3HT). However, the lower exciton dissociation and charge transfer are still the main factors that limit the improvement of P3HT-based OSCs. Herein, we designed one class of A2-A1-D-A1-A2 type non-fused electron acceptors and synthesized BTA34 and F-BTA34 by introducing benzo[d][1,2,3] triazole as the bridged unit. The dominated H-aggregation in F-BTA34 affords high degree of crystalline and proper phase separation when blended with polymer P3HT, which ensure efficient exciton dissociation and higher charge carrier mobility. Consequently, P3HT:F-BTA34 devices demonstrate a better performance with higher short-circuit current and fill factor. The blend of P3HT:BTA34 exhibits a broader distribution of the mixing domains, resulting in relative longer-lived charge species. This work provides useful strategies to design non-fused electron acceptors to match with P3HT from the perspective of simultaneously improving exciton dissociation and suppressing charge recombination.

Phosphate ions functionalized metal-organic framework-derived cobalt oxide with improved redox reactivity for high-performance alkaline aqueous Zn-ion batteries

Alkaline aqueous Zn/Co3O4 batteries (AZCBs) have captured significant attention within the field of scalable grid energy storage due to their high output voltage (>1.8 V), superior safety profile, and low manufacturing cost. Nevertheless, the intrinsic Co3O4 material experiences limitations in terms of low electronic conductivity and insufficient active sites, consequently constraining its electrochemical performance in AZCBs. To address this challenge, this investigation focuses on the use of phosphate ions functionalized Co3O4 (referred to as PCO) material derived from cobalt-based metal-organic frameworks (Co-MOFs) as a cathode electrode in AZCBs. Both theory calculations and experimental verification illustrate that the functionalization with phosphate ion enhances the active sites for electrochemical redox reactions and increases the electrical conductivity of intrinsic Co3O4. Consequently, a pouch cell configuration of PCO-2||Zn with the optimized PCO-2 sample as cathode exhibits a high capacity of 162.0 mAh g−1, a maximum energy density of 265.7 Wh kg−1, a maximum power density of 16.39 kW kg−1. Furthermore, excellent long-term stability is observed, with the capacity retention rate reaching 92.3 % over 5000 cycles at a high current density of 5 A g−1. Additionally, the constructed fibrous flexible solid-state device also demonstrates notable long-term stability, with a capacity retention of 96 % after 2000 cycles under a high current density of 10 mA cm−2, and performs well under different deformation statuses. This successful approach may hold potential for the exploration of other cathode materials, such as Mn or V-based compounds, which may exhibit high performance in aqueous zinc-based batteries.

Influence of nozzle temperatures on the microstructures and physical properties of 316L stainless steel parts additively manufactured by material extrusion

PurposeMaterial extrusion (ME) is a low-cost additive manufacturing (AM) technique that is capable of producing metallic components using desktop 3D printers through a three-step printing, debinding and sintering process to obtain fully dense metallic parts. However, research on ME AM, specifically fused filament fabrication (FFF) of 316L SS, has mainly focused on improving densification and mechanical properties during the post-printing stage; sintering parameters. Therefore, this study aims to investigate the effect of varying processing parameters during the initial printing stage, specifically nozzle temperatures, Tn (190°C–300°C) on the relative density, porosity, microstructures and microhardness of FFF 3D printed 316L SS.Design/methodology/approachCube samples (25 x 25 x 25 mm) are printed via a low-cost Artillery Sidewinder X1 3D printer using a 316L SS filament comprising of metal-polymer binder mix by varying nozzle temperatures from 190 to 300°C. All samples are subjected to thermal debinding and sintering processes. The relative density of the sintered parts is determined based on the Archimedes Principle. Microscopy and analytical methods are conducted to evaluate the microstructures and phase compositions. Vickers microhardness (HV) measurements are used to assess the mechanical property. Finally, the correlation between relative density, microstructures and hardness is also reported.FindingsThe results from this study suggest a suitable temperature range of 195°C–205°C for the successful printing of 316L SS green parts with high dimensional accuracy. On the other hand, Tn = 200°C yields the highest relative density (97.6%) and highest hardness (292HV) in the sintered part, owing to the lowest porosity content (<3%) and the combination of the finest average grain size (∼47 µm) and the presence of Cr23C6 precipitates. However, increasing Tn = 205°C results in increased porosity percentage and grain coarsening, thereby reducing the HV values. Overall, these outcomes suggest that the microstructures and properties of sintered 316L SS parts fabricated by FFF AM could be significantly influenced even by adjusting the processing parameters during the initial printing stage only.Originality/valueThis paper addresses the gap by investigating the impact of initial FFF 3D printing parameters, particularly nozzle temperature, on the microstructures and physical characteristics of sintered FFF 316L SS parts. This study provides an understanding of the correlation between nozzle temperature and various factors such as dimensional integrity, densification level, microstructure and hardness of the fabricated parts.

End Cap Effect on Solution-Processable Deep Blue Lasing Materials with Low-Amplified Spontaneous Emission Thresholds.

Organic lasers have attracted increasing attention owing to their superior characteristics such as lightweight, low-cost manufacturing, high mechanical flexibility, and high emission-wavelength tunability. Recent breakthroughs include electrically pumped organic laser diodes and an electrically driven organic laser, integrated with an organic light-emitting diode pumping. However, the availability of efficient deep blue organic laser chromophores remains limited. In this study, we develop two novel rigid oligophenylenes, end-capped with carbazole and phenylcarbazole groups, to demonstrate exceptional optical and amplified spontaneous emission (ASE) properties. These oligophenylenes are not only solution processable but also exhibit remarkably high solution photoluminescence quantum yields (PLQYs) of 90% and high radiative rates of 1.35 × 109 s-1 in the deep blue range. Our theoretical calculations confirm that the carbazole and phenylcarbazole end groups play a pivotal role in enhancing the optical transitions of the oligophenylene laser chromophores, thereby elevating their emission oscillator strengths. Remarkably, these materials demonstrate low solid-state ASE threshold values of 1.0 and 1.5 μJ/cm2 (at 431 and 418 nm, respectively). To the best of our knowledge, these ASE thresholds represent the lowest reported at these specific ASE wavelengths in the literature, regardless of whether they are solution-processed or thermally evaporated films. Furthermore, they exhibit excellent thermal and photostability, low triplet quantum yields, as well as negligible overlap of excited-state absorption within the ASE emission region, making them excellent candidates for a new class of deep blue materials for organic lasers. By integrating insights from theoretical calculations and experimental validation, our study provides a comprehensive understanding of the design principles behind these high-performing organic laser chromophores, paving the way for the development of advanced organic lasers with enhanced performance characteristics.

Importance of Controlling Cycling Conditions to Improve the Lifetime of Anthraquinone-Based Negolytes with a Potentially Low Cost of Manufacture

Organic redox flow batteries (RFB) in general and anthraquinones in specific have shown a great promise for developing cost-effective alternatives to vanadium RFBs. Two main hurdles, however, have been the fast fade rate and a high estimated cost of manufacture (COM) that have slowed down the scale up of organic RFBs. In this study, 1,8-dihydroxy-2,7-dicarboxymethyl-9,10-anthraquinone (1,8-DCDHAQ), 1,5-dihydroxy-2,6-dicarboxymethyl-9,10-anthraquinone (1,5-DCDHAQ) and 1,3,5,7-tetrahydroxyanthraquinone (THAQ) have been explored. These negolytes are expected to have a reasonably low COM due to their simple synthesis route. Additionally, these electroactive species have a low fade rate. Nevertheless, the fade rates are not adequately low for scaleup and commercialization purposes. Therefore, the effect of various factors including the electrolyte flow rate, cutoff voltages, SOC limits, and OH- concentration on the cycling performance have been explored in order to further reduce the fade rate.Our experimental analysis suggests that: (1) the electrolyte flow rate and the extent of mixing in the electrolyte reservoir may lead to inaccurate capacity utilizations and fade rates, (2) increasing the OH- concentration significantly lowers the fade rate and the effect continues even at concentrations higher than 1.0 M, (3) choosing an unnecessarily low discharge cutoff voltage has a detrimental effect on the fade rate of anthraquinones, (4) SOC limit is a very important tool that significantly lowers the fade rate. Through controlling these cycling conditions, the lifetime can be improved by at least a factor of 10. Under properly chosen conditions, the fade rate of 1,5-DCDHAQ and THAQ remains < 0.001%/day (< 0.4%/year). To further verify the effect of the operating conditions, cyclic voltammetry and HPLC techniques were used to identify and/or characterize the side products in the electrolyte. COM of 1,5-DCDHAQ and THAQ at scale are estimated to be 27.99 and 47.44 $/kAh (or 24.13 and 37.95 $/kWh), respectively. 1,8-DCDHAQ and 1,5-DCDHAQ are expected to have a similar COM.Due to the expected low COM for the abovementioned anthraquinones and their very low fade rate under optimum cycling conditions explored in this study, these molecules now present a distinctive prospect for developing and commercializing an affordable and long lifetime organic RFB chemistry.

Cyclic Olefin Copolymer-Based Reinforced Anion Exchange Membrane for Fuel Cell

Alkaline exchange membrane (AEM)-based fuel cells have emerged as a promising technology for clean energy conversion. In contrast to acidic proton exchange membrane in fuel cells, AEM fuel cells utilize an alkaline membrane AEM to facilitate the migration of hydroxide ions, offering advantages of economic earth-abundant catalysts and enhanced electrochemical reaction kinetics. However, AEMs that possess all characters of high ion conductivity, good chemical stability under high pH and temperature, robust mechanical properties, scalable synthesis, and low manufacturing costs are rare until now.Herein, we present quaternary ammonium-functionalized cyclic olefin copolymers (COCs) as a new class of alkaline stable and low-cost AEMs. Furthermore, we developed reinforced composite AEM by impregnating the quaternary ammonium-functionalized COC into a mechanically robust matrix. The prepared COC-reinforced membrane exhibits outstanding hydroxide conductivity of 127 mS/cm at 80°C and low swelling ratio in liquid water, and excellent mechanical properties with a tensile strength > 50 MPa, and elongation at break > 248%. The H2-O2 fuel cell test exhibited a maximum peak power density of >1.2 W cm-2 at 80°C with a low high-frequency resistance (HFR) under 0.1 Ohm cm2.

In-Depth Study on the Application of a Graphene Platelet-reinforced Composite to Wind Turbine Blades.

Graphene platelets (GPLs) are gaining popularity across various sectors for enhancing the strength and reducing the weight of structures, thanks to their outstanding mechanical characteristics and low manufacturing cost. Among many engineering structures, wind turbine blades are a prime candidate for the integration of such advanced nanofillers, offering potential improvements in the efficiency of energy generation and reductions in the construction costs of support structures. This study aims to explore the potential of GPLs for use in wind turbine blades by evaluating their impact on material costs as well as mechanical performance. A series of finite element analyses (FEAs) were conducted to examine the variations of mechanical performances-specifically, free vibration, bending, torsional deformation, and weight reductions relative to conventional fiberglass-based blades. Details of computational modeling techniques are presented in this paper. Based on the outcomes of these analyses, the mechanical performances of GPL-reinforced wind turbine blades are reviewed along with a cost-benefit analysis, exemplified through a 5MW-class wind turbine blade. The findings affirm the practicality and benefits of employing GPLs in the design and fabrication of wind turbine blades.

Design optimization and failure analysis of natural composite sandwich T-joints under pulling load conditions

This paper presents a structural analysis of composite sandwich T-joint systems respond to pulling loads. A finite element (FE) model of the T-joint structure was created with four geometrical models, and three different materials were used to compare the design and identify the failure locations. The stress-critical regions were identified within and beneath the Stringers, which are responsible for connecting the base and web panels and transferring loads. The FEA studies showed that T-joint fails due to high shear stress in the stringer, base panel (flange), web, and bolted joint areas. The combination of shear and tensile stress in the adhesive layer between the composite base panel and the stringers lead to failure. Furthermore, incorporating a circular hole in the web panel near the joint resulted in an 11.8 % reduction of failure load. Due to the intricate stress distribution and geometric variations in these joints, premature failure can occur. Therefore, meticulous attention is essential for wing structures at spar joints, especially under extreme load conditions. Despite the complex manufacturing process, the present conventional T-joint design is extremely effective. However, other designs for low-cost manufacturing were proposed and evaluated. The investigation determined that the sandwich structure exhibits a shear stress of 28.88 MPa and von Mises stresses of 57.75 MPa. These values are higher than those observed in design cases 1 and 2. Therefore, design case 3 is suitable for aeronautical applications.

Surface Molecular Engineering for Fully Textured Perovskite/Silicon Tandem Solar Cells.

Developing large-scale monolithic perovskite/silicon tandem devices based on industrial Czochralski silicon wafers will likely have to adopt double-side textured architecture, given their optical benefits and low manufacturing costs. However, the surface engineering strategies that are widely used in solution-processed perovskites to regulate the interface properties are not directly applicable to micrometric textures. Here, we devise a surface passivation strategy by dynamic spray coating (DSC) fluorinated thiophenethylammonium ligands, combining the advantages of providing conformal coverage and suppressing phase conversion on textured surfaces. From the viewpoint of molecular engineering, theoretical calculation and experimental results demonstrate that introducing trifluoromethyl group provide more effective surface passivation through strong interaction and energy alignment by forming a dipole layer. Consequently, the DSC treatment of this bifunctional molecule enables the tandem cells based on industrial silicon wafers to achieve a certified stabilized power conversion efficiency of 30.89 %. In addition, encapsulated devices display excellent operational stability by retaining over 97 % of their initial performance after 600 h continuous illumination.

Direct-Written Silver Electrodes for All-Solution-Processed Low-Voltage Organic Thin Film Transistors Towards Flexible Electronics Applications

Recent progress inprinted electronics has offered the possibility of fabricatingvarious organic-based electronic devices,such as organic light-emitting diodes (OLEDs) and organic thin film transistors (OTFTs).As one of the important deposition methods inprinted electronics, an inkjet printing technique offers the deposition of solution-processable materials onto a variety of substrates using simpler fabrication steps at lower processing temperatures, which is suitable for flexible electronic applications. Despite being the leading choice in OTFT fabrication,the clogging issues that frequently occurred at the printhead nozzle havenot only limitedthe material selection but also restrained the efforts to bring organic electronic devices to the market. Apart from that, although remarkable progress has been made to enhance the performance of the OTFT, the high operating voltage resulting from the low gate capacitance density of the inorganic oxide-based dielectric layer remains a critical limitation that hinders the practical application of the OTFT. Hence, in this paper, we propose a simple solution-based method to develop a low-voltageOTFT. This work utilized a direct-write printing technique to print silver source/drain and gate electrodes incorporated into a bottomgate bottom contact OTFT structure, a spin-coating deposition method to deposit both small molecule TIPS-pentacene organic semiconducting layer and high-kPVA dielectric layer. Notably, the proposed OTFT achieved a micrometre channel length with a saturation mobility of 4.49 × 10-1cm2/Vs, a threshold voltage of -1.5V, an on/off current ratio of 108, and a subthreshold swing of 66.8mV/dec whilethe overall fabrication temperature and operating voltage arekept below 150 °Cand -15 V, respectively.The direct ink writing technology incorporated into the high-kdielectric layer provides a new strategy to fabricate organic-related components,particularly the OFTFs at lower manufacturing cost and temperature towardsflexible and low-operating voltage electronic devices.

Design and analysis of flexible tilt mirror driven by piezoelectric thin sheet actuators

Optical tilt mirrors (OTM) enable the mirrors to achieve high precision posture adjustment, playing a significant role in various optical system applications in the fields such as active optics, adaptive optics, satellite communications and biomedicines. However, the rapid development of modern technologies has brought new challenges to OTM in terms of their dimension, operating space and dynamic performance. Herein, a novel biaxial optical flexible tilt mirror (OFTM) driven by four simple bonded-type thin sheet piezoelectric actuators was proposed, where the OFTM was designed based on the flexible bending motions of composite piezoelectric beams. Particularly, OFTM is mainly composed of PZT sheet and stainless steel substrate, and shows a dimension of 42 mm × 42 mm × 0.2 mm. A theoretical model of OFTM was established to accurately describe the relationship between input electric field and output pose based on elastic beam theory, where the relationship was verified by both finite element analysis and experimental results. Finally, an OFTM prototype was fabricated and presented good performance on motion behaviors. Compared with traditional fast steering mirror (FSM) and MEMS mirror, the developed OFTM shows low cost, small size and simple manufacturing process, which greatly extends the applications of OFTTM in emerging fields.

Organic montmorillonite modified polyethylene oxide based polymer electrolyte for dendrite-free flexible solid-state lithium metal batteries

Polyethylene oxide (PEO) based solid-state electrolytes are known for the low manufacturing cost and excellent processability, but their practical application is paved with thorns including the inferior ionic conductivity, low Li+ transfer number and insufficient Li dendrite blocking ability. Herein, we propose organic montmorillonite (OMMT) with expanded layer spacing (1.97 nm) as versatile fillers to construct PEO-OMMT electrolyte, in which OMMT not only increases Li+ transfer number (0.56) and ionic conductivity (7.15 × 10−4 S cm−1), providing fast ionic transport channels, but also endows PEO with high mechanical strength, resulting remarkable Li dendrite blocking ability (>2100 h). Additionally, the high dielectric constant and Lewis-rich polar sites of OMMT facilitate the dissociation of lithium salts and the rapid formation of LiF and Li3N-rich solid electrolyte interface layers. Impressively, the LiFePO4|PEO-OMMT|Li cell shows a high initial capacity (154.4 mAh g−1 at 0.5C) with ultralong cycling lifespan (>1200 cycles). Similarly, the LiNi0.83Mn0.05Co0.12O2|PEO-OMMT|Li cell retains a high discharge capacity of 151.5 mAh g−1 after 100 cycles at 0.2C. This work highlights the indelible contributions of OMMT functionalized fillers in improving the interfacial stability of PEO based solid-state electrolytes, paving a feasible avenue for the practical application of solid-state lithium metal batteries.

Environmental-Friendly, Long-Lastingly Moist Phase Change Gel with Tunable Cross-Linking Time for Effective Borehole Sealing.

Flexible environmental phase change gel (EPCG) is a promising and attractive material for borehole sealing due to its relatively lower usage, tunable cross-linking time, and potential degradable properties. However, conventional borehole sealing materials lack a lower manufacturing cost, lower reaction temperature, remarkable antimold function, and admirable hole sealing performance for long-term high-performance borehole sealing. Hence, it remains a critical challenge to realize a flexible phase-change gel featuring tunable cross-linking time, antimold ability and degradability, and long-lasting moist performance for high-performance borehole sealing. Herein, we illustrate a facile approach to fabricate the borehole sealing materials based on environmentally friendly, antimold, long-lasting moist composite phase-change gel fabricated from a modified cellulose gel polymer network. The prepared phase change gel presents adjustable cross-linking time with the initial setting time of 30-60 min, which could be used to seal holes with different drilling parameters. Furthermore, the fabricated gel illustrates reliable water retentiveness performance and antimold ability, assuring the long-period borehole sealing effect. Furthermore, EPCG has been applied for borehole sealing and shows great sealing ability and gas extraction performance. Therefore, this work paves the way to fabricate a flexible phase-change gel featuring tunable cross-linking time, antimold ability, and long-lasting moist performance for high performance borehole sealing.

Warm white-light emission from self-trapped excitons in double-chain metal halide hybrid

Low-dimensional metal halide hybrids with efficient warm white-light emission from self-trapped excitons (STEs) have attracted extensive attention for interior lighting because of their fascinating emission features including high colour rendition, excellent colour stability, and low manufacturing cost. Despite great efforts, the mechanism of STEs in one-dimensional (1D) metal halide hybrids is still unclear, which makes the way to regulate white-light emission is still worth exploring. Here, we prepared a double-chain organic-inorganic metal halide hybrid crystal, (C6H18N2)Pb2Br6∙H2O (DEPBH). Strikingly, DEPBH shows a warm white-light emission with an appropriate correlated colour temperature of 3714 K and high colour rendering index up to 89. Especially, further research reveals that STEs springs from the 1D core-shell quantum-wire frame play a crucial role in such warm white-light emission of DEPBH. This work offers a new route to fabricate single-component warm white-light phosphors in low-dimensional materials and will contribute to the further exploration of their relationships between crystal structure and optical properties.

Synthesis and characterizations of zinc oxide nanorods by cost effective aqueous hydrothermal technique for solid state lighting applications

Zinc oxide (ZnO) is recognized as the most promising and often utilized semiconducting material due to its exceptional physical, chemical, optical, and relatively low-cost production features, as well as its ecologically beneficial nature. ZnO is a prominent candidate owing to its wide band gap (3.37 eV at room temperature) as well as its high exciton binding energy (60 meV) for the next generation of ultraviolet and blue optoelectronic devices. This would be achieved through the development of hybrid heterostructured LED devices with low manufacturing costs by blending gallium nitride (GaN) with zinc oxide (ZnO), which serves as the most efficient opto-electronic device. Due to its high electron mobility, high transparency in the visible wavelength spectrum, and low work function, ZnO is also a highly investigated transparent conducting oxide thin film for several applications. Besides, their incredible optical capabilities, ZnO-based optical devices, such as light-emitting diodes (LEDs) and laser diodes (LDs), have drawn a great deal of interest. This reported research work demonstrates the growth of high-density, high-aspect-ratio ZnO nanorod (NR) arrays on p-type gallium nitride substrates employing low-cost facial aqueous hydrothermal syntheses with optimised growing conditions. Additionally, a top-down chemical etching technique is adapted for fabricating zinc oxide nanotubes. High-quality ZnO nanorods with high intensity that were a few microns long were found across the GaN substrate with FESEM analysis. The chemical composition of the grown nanorods is confirmed with EDAX analysis. The wurtzite crystalline structure and c-axis orientation of the grown ZnO NR-arrays were identified in X-ray diffraction studies. A Schimadzu UV–Vis–NIR spectrophotometer was used to record the optical curve, and the energy gap was determined to be 3.24 eV by plotting the Tauc curve. The good optical quality of the harvested nanorods is ensured by the narrow near-band-edge (NBE) emission at 384 nm and defect emission peaks detected through photoluminescence analyses. Grown specimens are also subjected to Raman spectrum analyses, and the obtained results are presented.