Commercial Chip Research Articles

Precise determination of reaction conditions for accurate quantification in digital PCR by real-time fluorescence monitoring within microwells

Real-time digital polymerase chain reaction (qdPCR) provides enhanced precision in the field of molecular diagnostics by integrating absolute quantification with process information. However, the optimal reaction conditions are traditionally determined through multiple iterative of experiments. Therefore, we proposed a novel approach to precisely determine the optimal reaction conditions for qdPCR using a standard process, employing real-time fluorescence monitoring within microwells. The temperature-sensitive fluorophore intensity presented the real temperature of each microwell. This enabled us to determine the optimal denaturation and annealing time for qdPCR based on the corresponding critical temperatures derived from the melting curves and amplification efficiency, respectively. To confirm this method, we developed an ultrathin laminated chip (UTL chip) and chose a target that need to be absolutely quantitative. The UTL chip was designed using a fluid‒solid‒thermal coupling simulation model and exhibited a faster thermal response than a commercial dPCR chip. By leveraging our precise determination of reaction conditions and utilizing the UTL chip, 40 cycles of amplification were achieved within 18 min. This was accomplished by precisely controlling the denaturation temperature at 2 s and the annealing temperature at 10 s. Furthermore, the absolutely quantitative of DNA showed good correlation (R2 > 0.999) with the concentration gradient detection using the optimal reaction conditions with the UTL chip for qdPCR. Our proposed method can significantly improve the accuracy and efficiency of determining qdPCR conditions, which holds great promise for application in molecular diagnostics.

An ultra broadband NIR phosphor LiScSnO4:Cr3+ with emission wavelength peaking at 900 nm for component analysis

Near-infrared phosphor conversion light-emitting diode (NIR pc-LED) is a widely used ideal NIR light source due to its unique advantages of low cost, energy saving, compactness and long operational lifetime. However, there is currently a scarcity of appropriate phosphor for NIR light sources utilized in spectral detection, with emission peak larger than 850 nm and steady spectrum output of ultra broadband spectra. Here, a broadband Cr3+ activated LiScSnO4 (LSS) phosphor (λex-max = 460 nm) matching the pump band of commercial blue LED chips has been developed, which shows a long wavelength NIR emission peaking at 900 nm. Cr3+ simultaneously replace the Wyckoff site co-occupied by Sc and Sn in LSS. Due to the difference of local environment of the specific crystal field, two different wide emission bands are caused. These two broad emission bands both contribute to the broadband luminescence with a full width at half maximum (FWHM) of 227 nm. Benefiting from the crystallography consistent Wyckoff position occupation of Cr3+ ions, the spectral distribution of LSS:Cr3+ exhibit excellent stability over a wide temperature span (80–423 K). The broadband NIR pc-LED prototype based on LSS:Cr3+ shows great potential in NIR spectrum detection, night vision imaging applications.

Enhancing quantum efficiency of Mn4+-doped fluoride phosphors through reverse doping strategy toward potential biological detection

Mn4+-doped fluoride red-emitting materials are renowned for their distinct characteristics, including fixed emission peaks and narrow spectral emission, rendering them highly favored in photoluminescent light-emitting diodes (LEDs). However, achieving ultra-high-concentration Mn4+ doping in fluoride phosphors is imperative to enhance quantum efficiency. Nevertheless, attaining such doping levels in metastable compound systems poses considerable challenges. In this study, we introduce an innovative reverse doping strategy, leading to the synthesis of Mn4+-doped cubic K2SiF6 phosphor (11.38 mol %) from hexagonal K2MnF6. Remarkably, this approach significantly improves the external quantum efficiency (EQE) to 66.7 % upon 450 nm excitation. Through systematic comparisons with conventional co-precipitation and ion exchange methods, our findings unequivocally demonstrate the superior efficacy of this approach in achieving high-concentration Mn4+ ion doping within relatively insoluble matrices. The successful application of our optimized phosphor enabled the fabrication of a red light-emitting diode (LED) that exhibits an exceptional photoelectric efficiency of 31.67 % at 350 mA, surpassing the performance of a commercial red LED chip. Furthermore, the stable red-light emission from the phosphor-converted LED (pc-LED) proves instrumental in rapid-response vascular imaging, showcasing the potential of our findings in advancing light sources for biological detection applications. This research provides valuable insights into enhancing red emission efficiency in slightly-soluble fluoride phosphors via novel synthetic strategy, unlocking possibilities for the development of highly efficient light sources in biological detection and imaging applications.

Genomic prediction based on selective linkage disequilibrium pruning of low-coverage whole-genome sequence variants in a pure Duroc population

BackgroundAlthough the accumulation of whole-genome sequencing (WGS) data has accelerated the identification of mutations underlying complex traits, its impact on the accuracy of genomic predictions is limited. Reliable genotyping data and pre-selected beneficial loci can be used to improve prediction accuracy. Previously, we reported a low-coverage sequencing genotyping method that yielded 11.3 million highly accurate single-nucleotide polymorphisms (SNPs) in pigs. Here, we introduce a method termed selective linkage disequilibrium pruning (SLDP), which refines the set of SNPs that show a large gain during prediction of complex traits using whole-genome SNP data.ResultsWe used the SLDP method to identify and select markers among millions of SNPs based on genome-wide association study (GWAS) prior information. We evaluated the performance of SLDP with respect to three real traits and six simulated traits with varying genetic architectures using two representative models (genomic best linear unbiased prediction and BayesR) on samples from 3579 Duroc boars. SLDP was determined by testing 180 combinations of two core parameters (GWAS P-value thresholds and linkage disequilibrium r2). The parameters for each trait were optimized in the training population by five fold cross-validation and then tested in the validation population. Similar to previous GWAS prior-based methods, the performance of SLDP was mainly affected by the genetic architecture of the traits analyzed. Specifically, SLDP performed better for traits controlled by major quantitative trait loci (QTL) or a small number of quantitative trait nucleotides (QTN). Compared with two commercial SNP chips, genotyping-by-sequencing data, and an unselected whole-genome SNP panel, the SLDP strategy led to significant improvements in prediction accuracy, which ranged from 0.84 to 3.22% for real traits controlled by major or moderate QTL and from 1.23 to 11.47% for simulated traits controlled by a small number of QTN.ConclusionsThe SLDP marker selection method can be incorporated into mainstream prediction models to yield accuracy improvements for traits with a relatively simple genetic architecture, however, it has no significant advantage for traits not controlled by major QTL. The main factors that affect its performance are the genetic architecture of traits and the reliability of GWAS prior information. Our findings can facilitate the application of WGS-based genomic selection.

Experimental Test on the Effect of Taheri Consciousness Fields on Thermoluminescence Phenomenon

In this paper, the combined effects of T-Consciousness Fields (TCFs) 1, 2, and 3 on the thermoluminescence phenomenon have been investigated. For this purpose, commercial thermoluminescent dosimeter chips GR-200 (LiF:Mg,Cu,P) were selected due to their high sensitivity to radiation. To assess the effects of TCFs on these chips, one GR-200 chip was discharged three consecutive times and radiated with beta radiation from a 90Sr source at an equivalent dose of 67.0 mSv (30 cycles in beta irradiator). Subsequently, its response (electric charge) and glow curve were measured. Then, the same chip was discharged three more consecutive times and irradiated under the same conditions, but in this case, TCFs were applied after discharge and simultaneously during irradiation. The results showed that the response of a single chip to TCFs decreased from 8.3% to 7.11% after the first to the third exposure. The observed results indicate a reduction in the response of GR-200 chip due to TCFs, thus experimentally confirming the effect of these fields on the thermoluminescence phenomenon.

Efficient CrIII Ion Governed Energy Migration for Broadband Near‐Infrared Emission in Ca3Sc2Ge3O12 Garnet Phosphor

AbstractThe rapid growth in phosphor‐converted near‐infrared light‐emission diodes (NIR‐LEDs) has led to the development of NIR emitter with high efficiency, broadband emission and high thermal stability. In this work, an efficient broad NIR emission of Cr3+ in novel Ca3Sc2Ge3O12 (CSGO) garnet‐based host was developed for the first time, which located at 700 to 1000 nm peaking at 817 nm with a broad bandwidth of ~128 nm. Such a broadband NIR emission originated from the preferential occupancy of Cr3+ in Sc3+ sites with weak octahedral field, which was manifested by the luminescence spectrum and decay behaviors. The Cr3+‐doping concentration was regulated to achieve a good internal quantum efficiency (IQE) of 72.1 % and a fantastic thermal stability (at 423 K, sustained approximately 85 % of the initial intensity). The mechanism for concentration and thermal quenching was further investigated. Benefiting from the excellent luminescence features, a prototype NIR‐LEDs was assembled via integrating the optimized samples with commercial blue InGaN LED chips, which exhibited a satisfactory photoelectric property and a brilliant performance in night vision. These results demonstrated the as‐obtained sample to be a great potential candidate for NIR‐LEDs.

Leveraging Commercial Microfluidic Chips for Zeta Potential Characterization

Bacteria zeta potential, ζ, is one of the key parameters for the deposition of bacteria on an electrode, also called electrophoretic deposition (EPD) and depends on the strain, suspension composition and pH. Measuring directly with a zetasizer is challenging due to the non-spherical shape of bacteria and the need for a lower conductivity medium which could affect the value of ζ. Electrokinetic measurements are usually performed with microchannels in PDMS [1] or in PMMA [2], both of which require expensive tools for the fabrication of either the mold or the microchannel itself. Reducing the cost and time needed to perform such measurements would enable the broader use of this technique. We anticipate solving this challenge with commercially available microfluidic chips as will be outlined in this study.Under an electric field E in a microchannel, the electrokinetic velocity of particles in a fluid is linked to two phenomena: electrophoresis (EP) due to the zeta potential of the particle and electroosmosis (EO) due to the zeta potential of the channel wall. PMMA microchannels (Microfluidic ChipShop) with 200 µl reservoirs together with a voltage sequencer (Labsmith) controlled with LabVIEW were used to characterize the velocity of 1 µm and 2 µm polystyrene beads with different surface functionalizations (nonfunctionalized polystryrene (PS), Sulfate-modified (SU-modified), Carboxylate-modified (CO-modified) and Amine-modified (AM-modified) from Invitrogen and Magsphere suspended in 10 mM HEPES (pH 7) by applying different voltages between the inlet and outlet platinum electrodes for 90 s. Recorded time-lapse fluorescent image sequences were analyzed with ImageJ and TrackMate. Electrokinetic velocities obtained by Particle Tracking Velocimetry (PTV) at different voltages were fitted with a linear fit with a high coefficient of determination allowing the extraction of the different particle zeta potentials, which are in good agreement with the control measurements performed with a Zetasizer Ultra (Malvern Panalytical) [3]. Further, this methodology was used to characterize a prevalent strain of E. coli, yielding values in agreement with the literature.The use of commercially available microfluidic chips in electrokinetic characterization could alleviate the need for microfabrication and allow the wider adoption of this characterization method. These measurements are ultimately critical to better understand the role of the zeta potential in EPD of microbes for an array of applications.[1] S. Antunez-Vela, et al., Anal Chem, 2020[2] Q. Wang et al., Science Advances, 2019[3] J. Cottet, et al. In preparation

Preparation and photoluminescence properties of high thermal stability Sr3Ga2Sn1.5Si2.5O14:Eu3+ red phosphors for high-power light-emitting diodes application

A series of Sr3Ga2Sn1·5Si2·5O14:xEu3+ (SGSSO:xEu3+) phosphors with excellent thermal stability were prepared by the solid-state reaction method. The phase and luminescence properties of the sample were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), diffuse reflectance spectroscopy, and photoluminescence (PL) spectra. Under the excitation of 395 nm, the SGSSO:Eu3+ phosphor exhibits strong red emission at 618 nm, which is attributed to the 5D0 → 7F2 transition of the Eu3+ ions. When monitoring the 618 nm emission peak, the excitation spectrum contains several excitation peaks with a maximum value of 395 nm, which is well matched with the commercial violet LED chips. In addition, the emission spectra of SGSSO:Eu3+ at different temperatures have also been studied. Pleasantly, the luminous intensity of the SGSSO:Eu3+ sample at 150 °C still maintains 80.2% of that at room temperature, demonstrating its good thermal stability and application potential in high-power LEDs. The mechanism for the high thermal stability of the as-prepared phosphor was also discussed. Moreover, the photoluminescence quantum yield of the optimized SGSSO:0.06Eu3+ phosphor can reach 62.7%. Finally, a warm white LED device with high color rendering index and low color temperature was prepared using the prepared SGSSO:Eu3+ phosphor as a red component, verifying the application potential of SGSSO:0.06Eu3+ in LEDs.

Boosting STE and Nd3+ NIR Luminescence in Cs2AgInCl6 Double Perovskite via Na+/Bi3+‐Induced Local Structure Engineering

AbstractCurrently, lanthanide (Ln3+) doped Pb‐free double perovskites (DPs) suffer from competitive emissions of the self‐trapped exciton (STE) and Ln3+. Herein, a new type of Nd3+‐doped Cs2AgInCl6 DPs with Na+/Bi3+ co‐alloying is developed. Benefiting from Na+/Bi3+‐induced local structural modification, both STE broadband visible luminescence and Nd3+ near‐infrared (NIR) emissions are boosted via free exciton sensitization. Specifically, a total 648‐fold enhancement in emitting intensities compared to the Na+/Bi3+‐free counterpart is realized, with a significantly improved NIR photoluminescence quantum yield (PLQY) from 0.16% to 30.3%. First‐principles density functional theory calculations, Raman spectra, and steady/transient‐state PL spectra verify the modification of local site symmetry, breakdown of parity‐forbidden absorption, and reduction of electron‐phonon coupling via Na+/Bi3+ doping. Finally, a compact vis–NIR broadband light‐emitting diode (LED) is designed by coupling the Na/Bi/Nd: Cs2AgInCl6 DP with a commercial ultraviolet LED chip, which shows promising applications in spectroscopic analyses and multifunctional lighting.

Synthesis and luminescent properties of Na5(La,Y) (MoO4)4: Sm3+ phosphors for solid-state lighting application

The Sm3+ and La3+ co-doped Na5Y(MoO4)4 orange-red phosphors were synthesized by solid phase method at 600 °C. The crystal structure, phase purity, thermal stability, and luminescence performance were comprehensively analyzed. Under 405 nm excitation, the phosphors emit the orange-red light because of the 4G5/2-6H5/2, 4G5/2-6H7/2, 4G5/2-6H9/2, and 4G5/2-6H11/2 transitions of Sm3+ ions. The enhancement of emission intensity with La3+ ions doping in phosphors is due to the environmental effect of the crystal field around the luminous center. When it is combined with commercial LED chips, the device emits orange-red light, and the luminescence spectrum coincides with the PR pigment absorption spectrum of the plant, indicating that the potential of Sm3+ and La3+ co-doped Na5Y(MoO4)4 phosphors in solid-state lighting application.

Two-site occupancy induced a broadband blue-emitting in Eu2+ doped Na3Ba2Ca(PO4)3 phosphor

During the process of developing commercial chips, the phosphors with single broadband emission are indispensable. In this report, a new ternary phosphate phosphor Na3Ba2Ca(PO4)3:Eu2+ has been successfully synthesized by the high-temperature solid-state reaction (HSSR) method, which shows broad emitting band in the range of 350–600 nm centered at 436 nm (FWHM ∼ 72.3 nm). The crystal structure of the Na3Ba2Ca(PO4)3 and Eu2+ doped Na3Ba2Ca(PO4)3 were determined by the Rietveld method, indicating the trigonal system with P31c space group. The selective two-site occupancy tendency of Eu2+ ions at Ba1O9 and Ca2O8 sites in the matrix was comprehensively revealed according to the split peaks (433 nm and 469 nm) at 298 K and 11 K, computational validation and fluorescence lifetime analysis of photoluminescence spectrum. Impressively, the optimal Na3Ba2Ca(PO4)3:0.02Eu2+ phosphor exhibits appropriate spectrum resemblance (SR) indexes (58.5% and 72.2%), proper thermostability (78.6%) and excellent chromaticity stability (Δx = 8.68 × 10−6 and Δy = 3.64 × 10−5). Besides, the phosphor prepared by HSSR owns the higher internal quantum efficiency of 62.1% in comparison with that synthesized by polymerizable complex (PC) method. The new phosphor can serve as a potential broadband and blue-emitting phosphor for the application of solid-state lighting and plant growth.

Ultrastable emissive perovskite nanocomposite via dual protection of polymer-grafted TS-1 zeolite for backlight display application

Instability of all-inorganic perovskite quantum dots (PQDs) driven by the inherent ionic nature poses a grand challenge towards their long-term stability in optoelectronic devices. Herein, we report the crafting of a highly stable dual-protected CsPbBr3 perovskite nanocomposite by capitalizing on the encapsulation of a hydrophobic Styrene-Divinylbenzene (St-Dvb) copolymer grafted hierarchical titanium silicalite-1 (TS-1) zeolite shell. Firstly, an optimal hot injection method was used to accommodate CsPbBr3 PQDs into hierarchical TS-1 zeolite. After the modification of terminated Si-OH groups on the surface of TS-1 by phenyltriethoxysilane (PTES), a subsequent polymerization of St and Dvb was implemented using azobisisobutyronitrile (AIBN) as initiator to result in the highly emissive CsPbBr3-TS@St-Dvb nanocomposite, exhibiting outstanding luminescent stability against heat, polar solvents, and UV light irradiation. The as-prepared CsPbBr3-TS@St-Dvb nanocomposite also showed strongly suppressed anion exchange and high compatibility in polymer matrix, enabling improved applicability for versatile lighting and optical display applications. Ultimately, a white light-emitting diode (WLED) composed of green-emitting CsPbBr3-TS@St-Dvb and red-emitting K2SiF6:Mn4+ phosphor onto a commercial blue InGaN LED chip with wide color gamut and excellent stability is demonstrated. This work highlights a judiciously-designed and hard-soft dual-protected strategy to produce ultrastable perovskite nanomaterials with high brightness and durability for backlight display application.

An IEEE-Compatible JTAG Test-Access-Port Controller for RSFQ Logic and Systems

JTAG, an IEEE-standard test protocol, is widely used for testing commercial and experimental CMOS chips but appears unused for testing superconducting chips. The test-access-port (TAP) controller described here facilitates the use of JTAG to reduce the cost – in time and effort – of testing superconductive circuits. Our RSFQ-based TAP controller shifts data serially through a scan chain that transfers data in parallel to and from a circuit under test. Suitably designed scan chains can provide initial values to superconducting circuits and retrieve results to explore circuit behavior. A control computer or an internet connection can operate our TAP controller through a simple five-wire interface. Our TAP controller implements the TAP part of IEEE standard 1149.8.1-2012 in an area of only 580 x 280 micrometers, less area than two bonding pads. Our TAP Controller design information and MIT SFQ5ee layout will be freely available.

Strategies for Mitigating Commercial Sensor Chip Variability with Experimental Design Controls.

Surface plasmon resonance (SPR) is a popular real-time technique for the measurement of binding affinity and kinetics, and bench-top instruments combine affordability and ease of use with other benefits of the technique. Biomolecular ligands labeled with the 6xHis tag can be immobilized onto sensing surfaces presenting the Ni2+-nitrilotriacetic acid (NTA) functional group. While Ni-NTA immobilization offers many advantages, including the ability to regenerate and reuse the sensors, its use can lead to signal variability between experimental replicates. We report here a study of factors contributing to this variability using the Nicoya OpenSPR as a model system and suggest ways to control for those factors, increasing the reproducibility and rigor of the data. Our model ligand/analyte pairs were two ovarian cancer biomarker proteins (MUC16 and HE4) and their corresponding monoclonal antibodies. We observed a broad range of non-specific binding across multiple NTA chips. Experiments run on the same chips had more consistent results in ligand immobilization and analyte binding than experiments run on different chips. Further assessment showed that different chips demonstrated different maximum immobilizations for the same concentration of injected protein. We also show a variety of relationships between ligand immobilization level and analyte response, which we attribute to steric crowding at high ligand concentrations. Using this calibration to inform experimental design, researchers can choose protein concentrations for immobilization corresponding to the linear range of analyte response. We are the first to demonstrate calibration and normalization as a strategy to increase reproducibility and data quality of these chips. Our study assesses a variety of factors affecting chip variability, addressing a gap in knowledge about commercially available sensor chips. Controlling for these factors in the process of experimental design will minimize variability in analyte signal when using these important sensing platforms.

Luminescence and energy transfer of Ce3+/Tb3+ activated fluoroborate BaGaBO3F2 as a color tunable phosphor

Ce3+/Tb3+ co-doped BaGaBO3F2 is a new rare-earth activated luminescent material with efficient green luminescence. The phosphor was synthesized via the conventional solid-state reaction and characterized by X-ray powder diffraction, photoluminescence, and decay lifetimes. The Ce3+/Tb3+ co-doped phosphor exhibits an efficient excitation between 280 and 420 nm, making it suitable for commercial near-UV chips. The 4f–5d transitions of Ce3+ sensitizer allow the phosphor to be excited by the near-UV light, resulting in green and blue luminescence from Tb3+ and Ce3+, respectively. By controlling Ce3+/Tb3+ doping, the luminescence color can be tuned from blue to green. The effective transfer of excitation energy from Ce3+ to Tb3+ of BaGaBO3F2 was confirmed by the spectral characteristics and decay lifetimes of samples with different doping concentrations. The dipole-quadrupole mechanism is responsible for the efficient energy transfer from Ce3+ to Tb3+, with a critical distance of 11.69 Å. These results demonstrate that Ce3+/Tb3+ co-doped BaGaBO3F2 is an efficient near-ultraviolet (NUV) excitation phosphor with tunable luminescence from blue to green. This material has the potential to be used as a down-conversion phosphor for NUV light-emitting diodes.

Study on the mechanism of high energy transfer efficiency of blue light excited Cr3+, Nd3+ co-doped near infrared phosphors.

Although Cr3+ as activator for Near infrared (NIR) phosphors has been widely studied, the peaks of Cr3+ emission spectra in most hosts are less than 1000 nm. Nd3+ as an activator in many hosts has a wide distribution of absorption peaks in the Ultraviolet-visible-Near infrared (UV-vis-NIR) band, especially in the 650-900 nm band for effective NIR to NIR Stokes luminescence (4F3/2→4I9/2, 4F3/2→4I11/2 transitions). Therefore, Cr3+, Nd3+ co-doping to achieve the emission in the NIR II region (1000-1700nm) is very meaningful. Here, we report La2CaZrO6(LCZO): Cr3+, Nd3+ NIR phosphors with emission spectra covering an ultra-wide range of 700-1400 nm and reveal their luminescence mechanism. The energy transfer efficiency of Cr3+ for Nd3+ can be as high as 88.4% under 471 nm blue light excitation. In the same case, the integrated intensity of the emission spectra of Cr3+, Nd3+ co-doped can reach 847% of that of Nd3+ alone and 204% of that of Cr3+ alone. Finally, the combination of commercial blue light chips and Cr3+, Nd3+ co-doped NIR phosphors shows great potential for applications in face recognition, night lighting, and angiography.

Ultra-broad Near-Infrared Emitting Phosphor LiInF4: Cr3+ with Extremely Weak Crystal Field.

Recent decades have witnessed a major development in broadband near-infrared (NIR)-emitting phosphors because of their potential applications in real-time nondestructive examination. These applications require the emission spectra of phosphors to be as broad as possible for efficient performance. Therefore, a blue-light excited LiInF4: Cr3+ phosphor with a NIR emission covering 700-1400 nm is successfully synthesized. Under 470 nm excitation, it shows broadband emission peaked at 980 nm with the full-width at half maximum of 210 nm. The structure and crystal field environment are investigated in detail, and the LiInF4: Cr3+ possesses a weak crystal field strength and strong electron-phonon coupling. An efficient NIR phosphor-converted light-emitting diode (pc-LED) is fabricated by the prepared LiInF4: Cr3+ phosphor and commercial blue diode chip, generating a NIR radiant flux of 5.54 mW at 150 mA drive current. Finally, the NIR pc-LED is successfully applied to identify the blood vessel distribution of the hand. This work suggests the potential of LiInF4: Cr3+ phosphor in applications.

Blue-excited red emission of CeO2:Eu3+, Al3+ cubic phosphor: Influence of Al3+ ion doping and Judd-Ofelt theory

In this work, a series of CeO2: 0.1 Eu3+, xAl3+ (x = 0, 0.1, 0.2, 0.3, 0.4, and 0.5 mol %) red phosphors could be efficiently excited with blue-light was successfully prepared by solid-state reaction. The X-ray diffraction confirmed the formation of a single-phase CeO2 cubic with high crystallinity. Under blue light (466 nm) excitation, the CeO2: Eu, Al phosphors showed dominant red emission of Eu3+ ions associated with 5D0 – 7F2 transition, which matched well with the commercial blue light InGaN chip. Significantly, the red emission intensity of sample co-doped with 0.3% mol Al3+ was enhanced by 8-times compared to the un-doped one. This result was caused by the presence of Al3+ ions forming oxygen vacancies and disturbing the symmetry of the host, leading to effectively enhanced red emission of the system. The enhanced red emission mechanism of the CeO2:Eu3+, Al3+ phosphors was further explained by Judd-Ofelt (J-O) theory analysis and radiative properties, including branching ratios (βr), transition probability (A), radiative lifetime (τcal), and stimulated emission cross-section (σe) of the phosphor were determined. The CeO2:0.1Eu3+, 0.3Al3+ phosphor shows intense red emission, a long lifetime (0.735 ms), and high quantum efficiency (49.46%), making it a suitable candidate as a red component for preparing low-cost WLEDs.

Hot-Trim: Thermal and Reliability Management for Commercial Multicore Processors Considering Workload Dependent Hot Spots

This work proposes a new dynamic thermal and reliability management framework via task mapping and migration to improve thermal performance and reliability of commercial multi-core processors considering workload-dependent thermal hot spot stress. The new method is motivated by the observation that different workloads activate different spatial power and thermal hot spots within each core of processors. Existing run-time thermal management, which is based on on-chip location-fixed thermal sensor information, can lead to suboptimal management solutions as the temperatures provided by those sensors may not be the true hot spots. The new method, called Hot-Trim, utilizes a machine learning-based approach to characterize the power density hot spots across each core, then a new task mapping/migration scheme is developed based on the hot spot stresses. Compared to existing works, the new approach is the first to optimize VLSI reliabilities by exploring workload-dependent power hot spots. The advantages of the proposed method over the Linux baseline task mapping and the temperature-based mapping method are demonstrated and validated on real commercial chips. Experiments on a real Intel Core i7 quad-core processor executing PARSEC-3.0 and SPLASH-2 benchmarks show that, compared to the existing Linux scheduler, core and hot spot temperature can be lowered by 1.15 1.31∘C. In addition, Hot-Trim can improve the chip’s EM, NBTI and HCI related reliability by 30.2%, 7.0% and 31.1% respectively compared to Linux baseline without any performance degradation. Furthermore, it improves EM and HCI related reliability by 29.6% and 19.6% respectively, and at the same time even further reduces the temperature by half a degree compared to the conventional temperature-based mapping technique.

Enhancement of color rendering index of stable lead-free perovskite WLEDs through incorporating green carbon dots

In this work, the carbon quantum dots@Cs2NaInCl6 (CDs@CNC) composites are presented by a facile solution synthesis. The obtained CDs@CNC composites maintain the octahedral morphology of original CNC host and the characteristic functional groups of original CDs. As a result, the rare-earth-free CDs@CNC composites exhibit green light emission with good stability for UV irradiation, heat, and humidity. In addition, CDs were combined with ion-doped CNC to obtain multicolor phosphor and the corresponding white light emitting diode (WLED) devices were fabricated by coating composites on commercial UV chips. The color render index (CRI) of WLEDs increases significantly from 66.24 to 90.95 while the cold-warm white fluorescence can be flexibly tuned by the change of excitation wavelength. The combination of CDs and double perovskites provide a new route to design white light emission phosphors, which could lead to the fabrication of next generation high-quality lighting devices.