Device Components Research Articles

Excellent Energy Storage Performance of Multi-Alternating-Layer Structured PMMA/PVDF Dielectric Composite at High-Temperature

Polymer dielectric capacitors have high power density and are an integral component of electronic and power device. Currently, the limited energy density restricts their further application. In this research, a novel method was designed to optimize performance of PMMA/PVDF composite via an alternating stacked multi-layer structure. And, the five-alternating-layer of PVDF-PMMA-PVDF-PMMA-PVDF (F-A-F-A-F) composite has excellent dielectric properties, for instance, a better dielectric constant (4.52@1 kHz) and a low dielectric loss (0.034@1 kHz). The discharge energy density (Ue) of it is significantly larger than that of PMMA and PVDF. Particularly, the Ue of F-A-F-A-F composite is increased by 83.0% (from 4.71 J/cm3 to 8.62 J/cm3) with charging-discharging efficiency of 60% at 80 °C. Moreover, the F-A-F-A-F composite achieves an excellent stability after 40,000 cycles. This composite has a wide range of potential applications in the field of traditional dielectric capacitor due to its good energy storage performance and cycle stability.

The application study of harmonization code in medical device adverse event reporting.

The reporting of adverse events in medical devices (MD) is a starting point of post-market surveillance and the most common source of initial safety signals. Because MD adverse events (AE) occur globally and involve high-profile international public health crises, international regulators implanted standard codes for MDAE reporting. This study aimed to assess the application of MDAE terminology and codes by providing examples of virtual events. An online survey was conducted among participants of the MD Training Program for Regulatory Authorities which provide International Medical Device Regulators Forum (IMDRF) adverse event terminology and codes, and six virtual MDAE cases. All 29 of the 72 participants were regulators. In all cases, most participants selected the broad (level 1) codes rather than the detailed (level 2 or level 3) codes. While responders selected a variety of codes for all annexes in case 1, over 50% of responders selected the intended codes in case 6. The codes for cause investigation were chosen more frequently than other annexes for device problem, components, and health effect. No differences were observed in code selection amongst different stakeholders. We identified the diversification in terminology and code selection for reporting MDAEs.

MDD-DETR: Lightweight Detection Algorithm for Printed Circuit Board Minor Defects

PCBs (printed circuit boards) are the core components of modern electronic devices, and inspecting them for defects will have a direct impact on the performance, reliability and cost of the product. However, the performance of current detection algorithms in identifying minor PCB defects (e.g., mouse bite and spur) still requires improvement. This paper presents the MDD-DETR algorithm for detecting minor defects in PCBs. The backbone network, MDDNet, is used to efficiently extract features while significantly reducing the number of parameters. Simultaneously, the HiLo attention mechanism captures both high- and low-frequency features, transmitting a broader range of gradient information to the neck. Additionally, the proposed SOEP neck network effectively fuses scale features, particularly those rich in small targets, while INM-IoU loss function optimization enables more effective distinction between defects and background, further improving detection accuracy. Experimental results on the PCB_DATASET show that MDD-DETR achieves a 99.3% mAP, outperforming RT-DETR by 2.0% and reducing parameters by 32.3%, thus effectively addressing the challenges of detecting minor PCB defects.

The charge transport properties of dicyanomethylene-functionalised violanthrone derivatives

The study of organic small molecule semiconductor materials as active components of organic electronic devices continues to attract considerable attention due to the range of advantages these molecules can offer. Here, we report the synthesis of three dicyanomethylene-functionalised violanthrone derivatives (3a, 3b and 3c) featuring different alkyl substituents. It is found that the introduction of the electron-deficient dicyanomethylene groups significantly improves the optical absorption compared to their previously reported precursors 2a–c. All compounds are p-type semiconductors with low HOMO–LUMO gaps (≈1.25 eV). The hole mobilities, measured from fabricated organic field-effect transistors, range from 3.6 × 10−6 to 1.0 × 10−2 cm2 V−1 s−1. We found that the compounds featuring linear alkyl chains (3b and 3c) displayed a higher mobility compared to the one with branched alkyl chains, 3a. This could be the result of the more highly disordered packing arrangement of this molecule in the solid state, induced by the branched side chains that hinder the formation of π–π stacking interactions. The influence of dicyanomethylene groups on the charge transport properties was most clearly observed in compound 3b which has a 60-fold improvement in mobility compared to 2b. This study demonstrates that the choice of the solubilising group has a profound effect on the hole mobility on these organic semiconductors.

Development of a device for assessment of aortic root parameters and positioning of aortic valve cusps during aortic valve-sparing root replacement

Background. A promising method of surgical treatment of aneurysms of the root and ascending aorta (AA) with unchanged aortic valve (AV) cusps is aortic valve-sparing root replacement (VSRR) with AV reimplantation (David procedure). To date, there are no clear indications to make a choice in favor of valve-replacing or valve-sparing intervention. The result of visual evaluation and the choice of treatment method based on the surgeon’s experience remains the main criteria. Objective. In the experiment to develop a prototype and method of application of the device for positioning of AV cusps, which will simplify and standardize aortic valve-sparing root replacement, improve the results and increase the reproducibility of these operations. Design and methods. Three-dimensional (3D) modeling of the device components was performed in the parametric open-source computer-aided design environment FreeCAD 0.20.1. Two-dimensional sketches were converted into three-dimensional models and exported as stl files for 3D printing. Solid components of the model were made of polylactic acid (PLA-plastic), elastic components were made of rubber-like photopolymer (Dropstil F556 10 shore A) also by 3D printing using SLA technology. Results. The device consists of 2 similar ring-sizers of variable diameter connected by three struts of variable length. In the upper part of each of the struts fastenings to the distal ring represents T-shaped cutouts for temporary locking of the suture-holders passed through the commissures of the AV cusps. For proximal locking of the aortic graft and the proximal ring-sizer, 3 U-shaped sutures are used, passed from inside to outside through the AV ring, the proximal part of the graft and taken in the tourniquets. The diameters of the ring-sizers can be varied between 25–40 mm by rotating a worm drive. A graft is placed on the inner side of the device, the suture-holders attached to the tops of the commissures are locked in the T-shaped notches in the upper parts of the struts. The device will allow changing the position of the coaptation point, coaptation square and performing hydraulic tests in different positions of the cusps, as well as variable diameters at the level of the AV ring and sinotubular junction (25–40 mm). When the target position of the coaptation point, coaptation area and satisfactory hydraulic test result are achieved, the cusps with commissures are locked inside the graft and the device is removed. Conclusion. A new device has been developed to facilitate, reproduce, and standardize VSRR. The results obtained will facilitate and accelerate the performance of VSRR, increase the reproducibility of the technique, and reduce the risks of complications.

Chemical Recycling of Epoxy Thermosets: From Sources to Wastes

As one of the most widely used thermosets due to its excellent performances, epoxy resin (EP) is widely used in various fields and often employed as a component of composite actuator devices, strengthening their mechanical properties. However, the expanding production of EP inevitably leads to the accumulation of waste end-of-life equipment and the corresponding increasingly serious environmental problems. This review summarizes the recycling strategies of EP, divided into two perspectives: recycling from wastes and sources. Chemical recycling is expected to be the future of waste EP treatment, and we discuss the chemical recycling methods of existing waste EP based on different mechanisms, including the selective cleavage of ester bonds, C–N bonds, and C–O bonds. On the other hand, epoxy vitrimer networks based on various dynamic covalent linkages are also outlined, which can respond to multiple external stimuli and provide materials with recyclability from the origin. Therefore, the use of epoxy vitrimer actuators can prevent waste generation throughout the whole lifecycle. We present some issues of concern in both waste-based and source-based recycling strategies and emphasize the significance of scaling-up. Finally, we summarized the current situation and present some future perspectives with the aim of making practical contributions to environmental issues.

Towards the Future of Ubiquitous Hyperspectral Imaging: Innovations in Sensor Configurations and Cost Reduction for Widespread Applicability

Hyperspectral imaging is currently under active development as a method for remote sensing, environmental monitoring and biomedical diagnostics. The development of hyperspectral sensors is aimed at their miniaturization and reducing the cost of components for the purpose of the widespread use of such devices on unmanned aerial vehicles and satellites. In this review, we present a broad overview of recent work on the development of hyperspectral devices’ configurations, studies aimed at modifying sensors and the possibility of reducing the cost of components of such devices. In addition, we will present the main trends in the development of hyperspectral device configurations for ubiquitous applications.

Bilayer Boost to UV Assisted Supercapacitors: Enhanced Performance with Transparent TiO2/MoO3 Heterojunction Electrode

Photo‐assisted supercapacitor is a promising smart device component for achieving both energy conversion and storage. The photo‐assisted functionality in a supercapacitor is realized through the choice of photo responsive electrode material under suitable illumination conditions. The well‐known electrochemically active electrode materials are wide band gap semiconductors which absorb strongly in UV light. However, most of the prior studies on photo‐assisted supercapacitors used visible light. Herein, we present a transparent TiO2/MoO3 bi‐layer heterojunction made by simple solution process as an efficient electrode for photo‐assisted supercapacitors under UV light illumination. The electrochemical performance of the electrode is significantly enhanced even with a less intense (0.05mW/cm2) UV light, compared to dark as well as the single layer electrode under same illumination condition. The highest areal capacitance of 63.25 mF/cm2 at 0.1 mA/cm2 is achieved, that surpasses most of the recent relevant reports. The synergetic effect of UV illumination and the built‐in potential at the type II heterojunction interface encourages ion insertion and better collection of the photo‐generated carriers. The unique bi‐layer design also leads to better rate capability features. Thus, the work presents a new prospect for the development of transparent energy storage devices to be used in future smart technologies.

Damage-free non-mechanical transfer strategy for highly transparent, stretchable embedded metallic micromesh electrodes

Stretchable, flexible, transparent electrodes garner significant research interest as indispensable components of flexible optoelectronic devices. However, frequent mechanical transfers during processing pose a considerable challenge in preparing electrodes of scalable size with superior performance and intact structure. Herein, we present a stretchable embedded metallic micromesh (SEMM) electrode with high optoelectronic and robust mechanical properties. The SEMM electrode is fabricated via a damage-free non-mechanical transfer strategy with the assistance of a bifunctional metal transition layer that serves as both a seed layer during electrodeposition and a sacrificial layer during stripping of the electrode. Consequently, the SEMM electrode features a scalable size and an intact structure. By optimizing the electrodeposition parameters, the SEMM achieves high optical transmittance (∼83 %) and low sheet resistance (0.22 Ω sq−1), with a figure of merit reaching 8600–53 times greater than that of commercial polyethylene terephthalate-indium tin oxide (PET-ITO). Furthermore, the SEMM exhibits excellent mechanical stability, enduring up to 60 % of tensile strain and maintaining almost constant normalized resistance after 20,000 bending cycles. Based on the SEMM, a transparent film heater yields rapid response time, low operating voltage, and fast defogging capability. This non-mechanical transfer strategy offers a compelling approach for enhancing the structural integrity and scalability of stretchable embedded transparent electrodes.

Azobenzene as an Effective Ligand in Europium Chemistry-A Synthetic and Theoretical Study.

The preparation and characterization of two novel europium-azobenzene complexes that demonstrate the effectiveness of this ligand for stabilizing reactive, redox-active metals are reported. With the family of rare earth metals receiving attention due to their potential as catalysts, critical components in electronic devices, and, more recently, in biomedical applications, a detailed understanding of factors contributing to their coordination chemistry is of great importance for customizing their stability and reactivity. This study introduces azobenzene as an effective nonprotic ligand system that provides novel insights into rare earth metal coordination preferences, including factors contributing to the coordinative saturation of the large, divalent europium centers. The two compounds demonstrate the impact of the solvent donors (tetrahydrofuran (THF) and dimethoxyethane (DME)) on the overall coordination chemistry of the target compounds. Apart from the side-on coordination of the doubly-reduced azobenzene and the anticipated N-N bond elongation due to decreased bond order, the two compounds demonstrate the propensity of the europium centers towards limited metal-π interactions. The target compounds are available by direct metallation in a straightforward manner with good yields and purity. The compounds demonstrate the utility of the azobenzene ligands, which may function as singly- or doubly-reduced entities in conjunction with redox-active metals. An initial exploration into the computational modeling of these and similar complexes for subsequent property prediction and optimization is performed through a methodological survey of structure reproduction using density functional theory.

CNT Functionalized GdCoBi Ternary Metal Oxide Nanocomposite for Electrochemical Detection of Perfluorooctanoic Acid and Energy Storage Applications

Perfluorooctanoic acid “Forever Chemical” presents substantial ecological challenges owing to its persistence and resistance to degradation. The study introduces a novel approach by integrating ternary metal oxides—Gd2O3, Co3O4, and Bi2O3 with carbon nanotubes to develop a versatile electrode material, CNT@GdCoBi NCs, which demonstrates dual functionality as both an electrochemical sensor for PFOA and a component for energy storage devices. The electrode exhibits outstanding electrochemical sensing performance, with a detection limit for PFOA of 4.9 ppb. Interference tests reveal the electrode's high selectivity for PFOA, with a tolerance limit of ≤5%. Practical application on various fruits, vegetables, and water samples shows an average relative standard deviation (%RSD) between 4.8 and 5.6%, underscoring the practical effectiveness of the CNT@GdCoBi NCs electrode. Furthermore, the CNT@GdCoBi NCs exhibit remarkable supercapacitor performance, achieving a specific capacitance of 1197F/g at 2A/g, which is 1.5 times higher than that of GdCoBi NCs. At a current density of 2A/g, the symmetric supercapacitor device demonstrates a specific capacitance of 269F/g, along with a high energy density of 52Wh/kg at a power density of 500W/kg. Additionally, the CNT@GdCoBi NCs electrode maintains good durability, retaining 94% of its capacitance after 10,000 cycles.

Impact of overvoltage on the mode transition of the spark gap switch: from edge breakdown to stochastic breakdown

Abstract Spark gap switch (SGS) is a fundamental but critical component for large-scale pulsed power devices, whose reliable operation is significantly affected by the breakdown characteristics of SGS. It is observed experimentally that, with the increase of overvoltage, the bridging position of the spark channel transits from edge to stochastic center. In this work, the influence of overvoltage on the breakdown process of a parallel-plate SGS with low geometric distortion of static electric field (<13%) between an atmospheric-pressure air gap of 5 mm is investigated by particle-in-cell/Monte Carlo collision simulation. It is found that, under a low overvoltage (ratio of applied voltage U a to static breakdown voltage U 0, U a/U 0 = 1.5), the streamers at the edge first bridge the gap before that in the central region, due to the field enhancement induced by the electrode curvature. Under higher overvoltage (U a/U 0 = 3), the synchronicity between streamers initiating from the center and those from the edge is greatly improved during the inception stage. After the streamers pass the middle of the gap, the field enhancement at the streamer front is more intensified and promotes the generation of fast electrons. These fast electrons rapidly magnify the difference among the propagating streamers by providing abundant seed electrons ahead of the discharge channel, which leads to the randomness of the bridging position. The results in this work demonstrate the relationship between overvoltage and streamer dynamics, which is beneficial for the performance improvement of SGS.

V doped Orth-Ga2O3: Half-metallic ferromagnetism, large magnetic anisotropy energy and high Curie temperature

Half-metallic ferromagnets have attracted intense interest worldwide and are considered to be an important component of spintronics devices. In this paper, an unpredicted Ga2O3 phase (named as Orth-Ga2O3) with good mechanical, dynamic, and thermodynamic stability is proposed by employing the adaptive genetic algorithm (AGA) crystal structure prediction approach. Surprisingly, V-doped Orth-Ga2O3 (V@Orth-Ga2O3) exhibits a strong ferromagnetic (FM) half-metallicity with a magnetic moment of 2 μB per formula. A detailed analysis of the density of states shows that the FM half-metallicity originates from the double exchange interaction between V-3d and O-2p orbitals. Besides, V@Orth-Ga2O3 has a big magnetic anisotropy energy (MAE) of 0.36 meV, mainly due to the (dxy, dx2-y2) orbitals of the V atom. According to Monte Carlo simulations, the Curie temperature TC of V@Orth-Ga2O3 is 225 K. The effect of carrier concentration and strain on the ferromagnetic stability of V@Orth-Ga2O3 system is also investigated. These unique magnetic properties make V@Orth-Ga2O3 an extremely promising material in spintronic nanodevices.

An Overview of the Future of Memory Cells: Advances in SSD Technology

This paper explores the topic of Solid-State Drives (SSDs) and NAND flash memory. Information of this paper is mainly obtained from authoritative academic websites and papers related to SSDs and flash memory. Memory cells are fundamental components in various electronic devices. In the field of data storage, SSDs represent the latest generation of storage devices, offering significantly better performance and functionality than traditional hard disk drives (HDDs). NAND flash memory chips are crucial component of SSDs, particularly 3D NAND, which exhibits exceptional performance and holds significant potential for future advancements. This paper will commence by providing an overview of SSDs and HDDs, followed by a comparison between NAND flash and NOR flash, and ultimately analysing the future of NAND flash memory technology employed in SSDs, with a focus on elucidating the advantages of 2D NAND over 3D NAND. Additionally, this paper explains a few challenges that NAND technology faces currently, as well as some possible solutions.

Growing Semiconductor Industry in India

This paper delves into the growing semiconductor industry in India, and its importance in every aspect of present and future high data processing speed. Semiconductors are crucial electronic components for quantum computing, artificial intelligence (AI), medical devices, aerospace and defence systems, etc. Thus, the use of semiconductors for these most important and future ease concepts, this paper is an understanding approach to the growing importance of semiconductors in India

Аналіз номенклатури мікроконтролерів для побудови елементів домашньої автоматизації

The subject of study and research in this article is the list of modern microcontrollers and technologies of the programming for creation elements of home automation, embedded systems, and components of Internet of Things. The goal is to analyze the product range and nomenclature of modern microcontrollers for creation of components of IoT systems and home automation considering an available resources and hardware implementation of interfaces. The tasks: to analyze a significant parameters of microcontroller for practical use; to analyze the product range and a modern manufacturers list of the most widely used microcontrollers; to analyze the main features of AVR microcontrollers; to perform an analysis of the advantages of STM32 microcontrollers; to analyze the capabilities of ESP32 microcontrollers; to perform the comparison of hardware resources of these three groups of microcontrollers. According to the tasks, the following results were obtained. Fourteen leading manufacturers of microcontrollers are analyzed with taking into account the bit length and a set of series and families of devices. The main characteristics and requirements for the practical application of microcontrollers for both the creation of embedded systems and for training and prototyping are highlighted. The reasons of the great popularity of the use of AVR microcontrollers by the community for training and learning of programming are identified. The capabilities of hardware resources and the advantages of using for embedded systems of the set of models of STM32 microcontrollers series are analyzed. The reasonability of the use of ESP32 microcontrollers for building of components of IoT systems and devices with Internet access is concluded. The comparison of the hardware resources of microcontrollers of three manufacturers is performed with taking into account the available size of program memory, the number of interfaces and pins. Conclusions. The main contribution and scientific novelty of the obtained results is that the performed analysis allows to simplify the process of a decision making about the selection of the required product range of modern microcontrollers for the creation of the components of the systems of home automation and Internet of Things with taking into account the available hardware resources, the number of pins, and the presence of hardware interfaces. This reduces the required efforts and costs at the initial stages of prototyping such systems, as well as during the porting to new microcontrollers and integrated environments of an already existing project.

Ultra-high precision nano additive manufacturing of metal oxide semiconductors via multi-photon lithography

As a basic component of the versatile semiconductor devices, metal oxides play a critical role in modern electronic information industry. However, ultra-high precision nanopatterning of metal oxides often involves multi-step lithography and transfer process, which is time-consuming and costly. Here, we report a strategy, using metal-organic compounds as solid precursor photoresist for multi-photon lithography and post-sintering, to realize ultra-high precision additive manufacturing of metal oxides. As a result, we gain metal oxides including ZnO, CuO and ZrO2 with a critical dimension of 35 nm, which sets a benchmark for additive manufacturing of metal oxides. Besides, atomic doping can be easily accomplished by including the target element in precursor photoresist, and heterogeneous structures can also be created by multiple multi-photon lithography, allowing this strategy to accommodate the requirements of various semiconductor devices. For instance, we fabricate an ZnO photodetector by the proposed strategy.

Synthesis of Ag Nanowires with High Aspect Ratio for Highly Sensitive Flexible Strain Sensor

AbstractIn recent years, the research and development of various flexible wearable devices have rapidly advanced due to the continuous introduction of flexible electronic product. These devices have found applications in health monitoring, cardiovascularcare, internal and external workload, and more.Flexible sensors, being a vital component of flexible devices, determine the functionalities and performance capabilities of the devices. Metal nanomaterials, especially silver nanowires, are widely used in flexible sensors in past research due to their great advantages in flexibility and sensitivity. In this work, Silver nanowires with aspect ratios of 600, 1000, and 1400 were synthesized by adjusting the synergy of Br‐ and Cl‐, along with other process parameters, leading to an improved production efficiency of silver nanowires.The stability of the conductive network is enhanced when the aspect ratio of silver nanowires is 1000 and 1400.The sensor demonstrated high sensitivity at high strain, along with an extended strain range.Moreover, it was observed that increasing the aspect ratio of silver nanowires led to a more stable conductive network, thus enhancing the sensor's stability with over 10000 stretching cycles. under the appropriate deposition density, silver nanowires with aspect ratio of 600 have high sensitivity to low strain, and silver nanowires with aspect ratio of 1400 have high sensitivity to high strain, up to 247.3. Introducing microstructures on the surface of PDMS resulted in an increased maximum sensitivity of the sensor with decreasing microstructure size, reaching a maximum sensitivity of 322.2.

The Influence of Polymer Impregnating Materials on Structural Strengthening of 3D Printed Sand Molds Produced by Binder Jetting Method.

Additive manufacturing offers great potential for various industrial solutions; in particular, the binder jetting method enables the production of components from various materials, including sand molds for casting. This work presents the results of an extensive set of experiments aimed at enhancing the structural strengthening of 3D-printed sand molds. Structural strengthening was achieved by impregnating the sand-printed structures with two polymer materials: epoxy resin and silicone varnish. Impregnation was performed with variable parameters, such as temperature, pressure, and time. Structural strengthening using polymers was investigated by analyzing the flexural strength and impact resistance of the impregnated products and comparing these obtained values with the reference material in terms of impregnation parameters and the polymer used. Microstructural observations and an analysis of the pore filling were also performed. This approach allowed for a full assessment of the influence of processing parameters and the type of polymer used for impregnation on the properties of sand-printed structures, which allowed for identifying the most optimal method to be used to strengthen the sand molds for casting the components for electrical devices. As a direct proof of concept, it was shown that impregnation with polymeric materials could effectively strengthen the sand mold, increasing its flexural strength and impact resistance by over 20 times and 5 times, respectively. A full-scale mold was printed using binder jetting, impregnated with epoxy resin at 65 °C, and used to successfully fabricate a fully functional electrification device.

Ultra-broadband emission from Mg7Ga2GeO12:Ni2+,Cr3+ phosphor spanning the NIR I–III regions for spectroscopy applications

Ultra-broadband near-infrared (NIR) lighting sources covering NIR Ⅰ to III regions are pivotal components for NIR spectroscopy devices. However, achieving ultra-broadband and efficient emission covering the entire NIR Ⅰ to III regions remains a significant challenge. To address this, we selected Mg7Ga2GeO12 as host material to realize ultra-broadband NIR emission. Density functional theory calculations on formation energies confirmed the feasibility of doping both Ni2+ and Cr3+ within Mg7Ga2GeO12. Band structure calculations reveal a significantly reduced band gap upon the doping of Ni2+. Following that, we synthesized Mg7Ga2GeO12:Ni2+ through conventional solid-state-reaction method. This phosphor exhibits broadband NIR emission with a full-width-at-half-maximum of 377 nm in the range of NIR II ∼ III (1100–2100 nm). To further enhance the emission efficiency, we co-doped Mg7Ga2GeO12:Ni2+ phosphor with Cr3+. This co-doping strategy not only dramatically enhances the Ni2+ emission intensity, but also extends the lower limit of emission band to 600 nm. However, a spectral gap around 1150 nm remains between Cr3+ and Ni2+ emission centers. To bridge this spectral gap, we employed LiScSiO4:Cr3+ phosphor alongside Mg7Ga2GeO12:Ni2+,Cr3+ phosphor to fabricate a phosphor converted LED (pc-LED) with ultra-broadband NIR emission covering entire NIR Ⅰ to III regions. By utilizing this pc-LED as the lighting source for NIR spectral detection, multiple organic functional group signals can be identified simultaneously in NIR II and III bands from 1000 to 2100 nm. The performance of such an NIR pc-LED not only confirms the application potential of Mg7Ga2GeO12:Ni2+,Cr3+ phosphor in non-destructive spectral analysis but also underscores the feasibility of combining two phosphors to achieve ultra-broadband NIR pc-LEDs, rendering them suitable to be lighting sources for portable spectrometers.