Photoluminescence Emission Peak Research Articles

Synthesis and Optical Properties of CdSeTe/CdZnS/ZnS Core/Shell Nanorods.

Semiconductor nanorods (NRs) have great potential in optoelectronic devices for their unique linearly polarized luminescence which can break the external quantum efficiency limit of light-emitting diodes (LEDs) based on spherical quantum dots. Significant progress has been made for developing red, green, and blue light-emitting NRs. However, the synthesis of NRs emitting in the deep red region, which can be used for accurate red LED displays and promoting plant growth, is currently less explored. Here, we report the synthesis of deep red CdSeTe/CdZnS/ZnS dot-in-rod core/shell NRs via a seeded growth method, where the doping of Te in the CdSe core can extend the NR emission to the deep red region. The rod-shaped CdZnS shell is grown over CdSeTe seeds. By growing a ZnS passivation shell, the CdSeTe/CdZnS/ZnS NRs exhibit a photoluminescence emission peak at 670 nm, a full width at a half maximum of 61 nm and a photoluminescence quantum yield of 45%. The development of deep red NRs can greatly extend the applications of anisotropic nanocrystals.

Wavelength-tunable photoluminescence of CsPbBr3 microcrystal via in situ halogen doping

Lead halide perovskite semiconductors have received significant attention in recent years as promising candidates for optoelectronic applications. Their controllable bandgap in nanostructures (nanocrystals, nanowires) has been widely and successfully investigated. Intentionally manipulating the atomic behavior with dopants in their macroscopic structure with high quality and stability is still challenging. We studied the crystal structure and photoluminescence (PL) behavior of the anion (Cl) doped CsPbBr3 microcrystals. The doped microcrystal with a low doping concentration has shown a large wavelength-tunable PL emission from 535 nm to 457 nm. Two separate emission peaks (blue and green) are carefully studied in the excitation power dependent PL spectra. The doping and excitation endow the perovskite microcrystal adjustable PL emission band and peak intensities, which may serve as a new degree of manipulation freedom in the color-tunable display and functional optoelectronics.

Improving Photocatalytic Performance through Incorporation of Various Cations in A-site of Double Perovskite Material (Cs0.50MA0.50)2SnI6 for Degradation of Methylene Blue Dye Pollutant under Visible Light Irradiation

In this article, undoped double perovskite materials like caesium tin iodide (Cs2SnI6), methyl ammonium tin iodide [MA2SnI6: MA denotes CH3NH3+] and mixed double perovskite material [(Cs0.50MA0.50)2SnI6] were synthesized using a wet chemical methodology. The crystal structure confirmation, optical properties, thermal properties, surface morphology and presence of elemental composition of the prepared samples using XRD, UV, TGA and FESEM-EDAX analyses were thoroughly investigated. The synthesized materials were employed as photocatalysts to degrade methylene blue dye within 120 min under visible light. An increase in the optical properties of the synthesized double perovskite materials was confirmed by ultraviolet (UV) analysis, which showed that the introduction of various cations into the perovskite material at the A-site shifted the photoluminescence (PL) emission peak to the red. TGA results demonstrated that (Cs0.50MA0.50)2SnI6 has greater thermal stability, which was confirmed by the presence of 43% of sample despite the temperature reaching almost 870 ºC. Doped double perovskite material (Cs0.50MA0.50)2SnI6 exhibited increased photocatalytic activity, with methylene blue dye degradation efficiency attaining 89% after 120 min of visible light irradiation, which is greater than pure double perovskite materials. The photocatalytic degradation of methylene blue dye is mostly facilitated by hydroxyl radicals and holes, according to a radical trapping experiment that we conducted by employing different scavengers. The results of the current work showed that doped double perovskite materials [(Cs0.50MA0.50)2SnI6] exhibit high thermal stability as well as higher photocatalytic activity than pure double perovskite materials. A possible photocatalytic reaction process is also diagrammatically using the band positions of double perovskite materials found using Mott-Schottky plots , which confirms that the synthesized double perovskite material has an N-type semiconductor nature.

Thermally stimulated luminescence properties of Mn-doped MgAl2O4 translucent ceramics

MgAl2O4 translucent ceramics doped with Mn were fabricated by spark plasma sintering, and optical and dosimetric properties were evaluated. The 1% Mn-doped MgAl2O4 translucent ceramic exhibited a photoluminescence emission peak at 520 nm due to Mn2+. Thermally stimulated luminescence (TSL) glow peaks of the Mn-doped MgAl2O4 translucent ceramics were observed at around 60 and 260 °C. Moreover, the TSL intensity increased as the heating temperature rose to 490 °C. TSL spectra confirmed that Mn2+ had a role of recombination centers in the TSL process. The 0.01% Mn-doped MgAl2O4 translucent ceramic showed a proportional relationship between the TSL intensity and irradiation doses ranging from 0.1 to 1000 mGy.

Display and energy storage applications of copper doped nanoceria

In the current study CeO2: Cu2+ (0–11 mol%) NPs were synthesized by Aloevera mediated solution combustion method followed by calcination. The synthesized samples were described and their multifunctional characteristics, including photoluminescence, sensor, and supercapacitor features were covered thoroughly. Bragg reflections confirmed single-phased CeO2: Cu2+ NPs with cubic spinel structure belonging to space group Pm3m(221). Crystal size was estimated using both the Scherrer and W-H plot method. The energy gap was computed from the Wood-Taucs relation. The crystallite size increases whereas the energy band gap increases with an increase in dopant concentration. The photoluminescence emission peaks of CeO2:Cu2+ (1–11 mol%) NPs, CIE, and CCT λex= 340 nm unambiguously show that the current nanophosphor might be a promising nanophosphor material for white and blue LEDs. The Cyclic voltammetry analysis was performed on as obtained CeO2: Cu2+ NPs for oxidation and redox peaks. EIS revealed that ion transport kinetics and super-capacitance values were obtained from GCD analysis. Specific capacitance values are found to be in the range 18 to 61 F/g for CeO2: Cu2+ 1 to 11 mol % NPs respectively which are in good agreement with the values obtained from CV analysis. Thus, the present synthesized material might find applications in the field of display technology and energy storage materials.

Structural, thermal and optical characteristics of Fe 1−X Zr X alloy by using mechanical milling approach: influence of Zr4+ ion

By changing Zr concentrations, Fe1-x-Zrx(x = 0.25 & 1 at%) alloys were successfully produced in an argon atmosphere using the mechanical alloying method. The produced Fe1-x-Zrxalloys were characterized by x-ray diffraction (XRD), transmission electron microscopy (TEM), energy dispersion x-ray analysis (EDAX), fourier transform infrared spectroscopy (FTIR), thermogravimetry analyzer (TG-DTA), ultraviolet-visible spectroscopy (UV–vis) absorption, and photoluminescence (PL) spectroscopy. According to XRD pattern analysis, the prepared alloys had a cubic crystalline structure and complete solid solution formation. The prepared alloy samples the average crystallite size was calculated using the Scherrer formula. The average crystallite size for the 0.25 at% Zr concentration is found to be 7.79 nm and 11.8 nm for the 1 at% Zr concentration. Lattice parameter changes are a very important tool for confirming the complete dissolution of the Zr atom in the Fe matrix.The TEM-dark field image confirms that the grain size is in the nanometric range (<100 nm). TEM-SAED spotty continuous ring pattern confirmed the complete solution formation is well correlated with the XRD results. The elemental composition of materials can be determined quantitatively through energy dispersive x-ray analysis in the Fe1-x-Zrxalloy. The elemental distribution of the mechanically alloyed samples shows that Zr elements are homogeneously distributed in the Fe matrix. Bands at 3428 cm−1 in the FTIR spectrum have been linked to O–H stretching vibrations. CH2 and CH stretching vibrations were associated with peaks of about 2920 cm−1 and 2850 cm−1. The weight loss and gain changes were observed and represented in the TG-DST graph; we found that overall weight changes are + 10.7% (gain) at 1023 °C for Fe 1-x-Zr x (x = 0.25 at%) alloy. However, when compared to 0.25 at% of Zr alloy, Fe-Zr (x = 1 at%) exhibits a low weight gain (+ 6.54%). The UV–visible absorbance edge revealed a blue shift when Zr was added, indicating alloy production. The energy band gap of materials was calculated using UV–vis, and it has been observed that the band gap reduces as Zr concentration increases. Zr was added to Fe1-x-Zrxalloy nanoparticles, resulting in 514 nm and 775 nm emission wavelengths. The greatest emission wavelengths and strong flawless sharp emission peaks were discovered to be between 450 nm and 550 nm. The higher PL emission peak was 514 nm at 0.25 at% of Zr.

Effect of Manganese Doping in SnO2 Thin Films and its NO2 Gas Sensing Performance

By using an automated nebulizer spray pyrolysis technique with varied concentrations of manganese chloride (0 - 3%) in the spray solution of tin chloride, thin films of pure and manganese-doped tin oxides (Mn-SnO2) were deposited. X-ray diffraction investigations indicated that 2% Manganese chloride concentration in the spray solution promoted development along (200) and (220) directions. The preferred growth direction in the (200) and (220) planes decreased with increasing manganese chloride doping concentration (2-3%) in the solution. The surface morphology of the films had changed as a result of adding Manganese as a dopant. Compositional analysis was carried out using EDAX. From UV-Vis spectroscopy, the optical properties of the SnO2 and Mn-SnO2 thin film were observed; the maximum optical absorbance was in the wavelength range of 300 - 400 nm. The concentration of Mn in the films affected the intensity of the photoluminescence emission peak detected at 347 and 392 nm for pure SnO2 and Mn-SnO2 films, respectively. The gas sensing performance of the films was examined by dynamic method against NO2 gas, at an operating temperature of 250 °C and 400 ppm gas concentration. Mn-SnO2 films achieved quick response and recovery times of 17 s and 34 s.

Defect analysis of 1-MeV electron irradiated flexible InGaAs solar cells by deep-level transient spectroscopy and photoluminescence

1-MeV electron irradiated InGaAs flexible solar cells were investigated based on solar cell I–V characteristics, external quantum efficiency, photoluminescence, and deep-level transient spectra (DLTS) mesurements. The electrical parameters of the solar cells, including Rs and Rsh, were extracted from the I–V curves. With an increase in irradiation fluence, the electrical and optical characteristics of the solar cells continuously degraded. The Voc, Isc, and Pmax values decreased to 83.16%, 81.96%, and 68.88% of their initial values, respectively, when the irradiation fluence was increased to 2 × 1015 e/cm2. Photoluminescence (PL) emission peak intensity decreased to 0.54% of its original value, and the minority carrier lifetimes derived from fitting PL emission spectra were reduced to 1.25%. DLTS technique was used to analyse the irradiation-induced defect properties. Similar fitting values for the minority carrier lifetimes were obtained from the PL and DLTS measurements.

Solvent/ligand free synthesis of Mn-doped CsPbCl3 perovskites with enhanced fluorescence for color sensor of bromide ions

For the detection of anions from wastewater, the perovskite materials synthesized should have suitable stability and be as hydrophilic as possible, and it’s not appropriate to introduce organic ligands. Mechanochemical reaction can avoid the use of organic solvents and provide improved stability for the perovskite materials due to their large particle size and compact structure, but their fluorescence is often too weak. To solve this problem, the Mn2+ doping effect was introduced into the CsPbCl3 crystals, and their synthesis doping strategies driven by mechanical grinding were systematic studied. The optimal Mn2+-doped CsPbCl3 (CsPbCl3:Mn) product was obtained by optimizing the synthesis conditions of Mn2+ source, grinding time on each reaction stage, Mn: Pb feeding ratio, and the sintering temperature. CsPbCl3:Mn had the same crystal structure as its undoped counterpart, while an obvious photoluminescence emission peak at 604 nm was obtained, which was originated from the doped Mn2+ ions. CsPbCl3:Mn had good stability against the ethanol environment and there was no organic ligands to hinder the ion exchange between Cl- and Br- from wastewater. Through testing the color difference of the resultant powders, a linear relationship with high correlation coefficient above 0.99 was established between chroma and Br- concentrations, and the Br- concentration in wastewater was accurately determined, demonstrating a promising application prospect of CsPbCl3:Mn in the fast detection of Br- ions.

Optimized structural, optical, and electrical properties of spin-coated Pt(II) octaethylporphyrin thin films for optoelectronic applications

Octaethylporphyrin (PtOEP) is an organic molecule that has unique optical properties, such as high fluorescence quantum yields, strong light absorption, etc. Here we investigate the structural, optical, and electrical characteristics of spin-coated PtOEP thin film. X-ray diffraction (XRD) patterns indicated an increase in the crystallite of the annealed film. Field emission-scanning electron microscope (FESEM) images clearly showed agglomeration and an increase in the nanoparticle size of the annealed film. The Raman spectra of the thin films revealed symmetrical peak positions and improved peak strength for the annealed film. UV-Vis-NIR and photoluminescence (PL) spectroscopy were used to examine optical characteristics. The findings demonstrated that energy gap and PL peak emission were significantly influenced by the grown crystallite size as well as a decrease in lattice defect concentration at the grain boundary during annealing. The optical constant and interband transition strength spectra (Jcv) were estimated and addressed. Based on the linear refractive index and optical gap, third-order nonlinear susceptibility χ(3), nonlinear refractive index n2, and two-photon absorption coefficient, βc of spin-coated PtOEP thin films were calculated and discussed. Finally, the dark current-voltage (J-V) curves were utilized to assess the diode parameters, specifically the zero-bias barrier height (ΦB) and the ideality factor (n), for the ITO/PtOEP/Al diode using thermionic emission theory. Additionally, an investigation was conducted to examine the conduction mechanism of the ITO/PtOEP/Al diode under both forward and reverse bias voltage conditions. On the basis of these findings, spin-coated PtOEP thin films were concluded to be helpful in producing cutting-edge optoelectronic devices.

Solid superacid catalysts promote high-performance carbon dots with narrow-band fluorescence emission for luminescence solar concentrators

Facile and efficient method for constructing carbon dots (CDs) with narrow full width at half maximum (FWHM) is a major challenge in the field, and researches on regulating the FWHM of CDs are also rare and scarce. In this work, we delved into the synthesis of CDs with narrow fluorescence emission FWHM (NFEF-CDs) in the m-phenylenediamine (m-PD)/ethanol system, utilizing solid superacid resin as catalyst with solvothermal method. The resulting NFEF-CDs exhibit a photoluminescent (PL) emission peak at 521 nm with a narrow FWHM of 41 nm, an absolute PL quantum yield (QY) of 80%, and display excitation-independent PL behavior. Through comprehensive characterization, we identified the protonation of edge amino on NFEF-CDs as the key factor in achieving the narrow FWHM. Subsequently, we validated the broad applicability of solid superacid resins as catalysts for synthesizing CDs with narrow FWHM in the m-PD/ethanol system. Finally, we utilized a self-leveling method to prepare NFEF-CDs film on the surface of poly(methyl methacrylate) (PMMA) substrate and investigated the solid-state fluorescence properties of NFEF-CDs as well as their performance as luminescence solar concentrator (LSC) for photovoltaic conversion. The results revealed that the as-prepared LSC exhibit an internal quantum efficiency (ηint) of 42.39% and an optical efficiency (ηopt) of 0.68%. These findings demonstrate the promising prospects of NFEF-CDs in the field of LSCs and provide a theoretical basis for their application in photovoltaic conversion.

Photophysical properties of nitrogen-doped carbon quantum dots synthesized by graphite

Here, nitrogen-doped carbon quantum dots (N-CQDs) were successfully synthesized by the solvothermal method using graphite as the carbon source and N,N-dimethylformamide as the nitrogen source. We characterized the structure and chemical constitution of N-CQDs using X-ray diffraction, Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy. We investigated the pump- and temperature-dependent photoluminescence (PL) properties and the dynamic exciton recombination processes of N-CQDs, using both steady-state and time-resolved PL techniques. The spectral results show that the PL emission peak located at 518 nm at room temperature, mainly originates from the n-π∗ transition on the surface of N-CQDs. The pump fluence and PL integral intensity were analyzed to demonstrate the existence of single-photon excitation under the 405 nm laser excitation. As the temperature increases, the non-radiative transition gradually increases, which decreases the PL intensity, the full width at half maxima first narrows and then widens and the PL lifetime gradually decreases. Furthermore, we combined the N-CQDs with chip to prepare light-emitting diode (LED). The resulting chromaticity coordinate was obtained to be (0.29, 0.40). This study offers a comprehensive understanding of the luminescence mechanism in N-doped CQDs and introduces a novel approach for the quickly fabrication of full-color display LEDs.

Investigating the effect of H+-ion irradiation on layered α-MoO3 flakes by defect engineering

Ion irradiation is a versatile and convenient tool for modifying the optical, electrical, and catalytic properties of two-dimensional (2D) materials through controlled induction of impurities and defects. The behavior of 2D materials under ion irradiation is interesting, which needs to be explored in the contest of their optoelectronic applications. In the present work, we have reported the effect of H+-ion irradiation on layered α-MoO3 flakes by defect engineering. Initially, the α-MoO3 crystals were synthesized using the physical vapor deposition technique followed by mechanical exfoliation of an as-grown crystal to obtain α-MoO3 flakes of different thicknesses. Then, the exfoliated flakes were exposed to H+-ion/proton irradiation with a fluence of 1 × 1016 ions/cm2 using a 30 keV source. After irradiation, new photoluminescence (PL) emission peaks were observed at different positions in the range of ∼2.4–1.9 eV, which was found to be absent in pristine flakes. Raman studies revealed non-uniform oxygen vacancy distribution in H+-ion irradiated α-MoO3 flakes, which affected the PL peak positions. Additionally, first-principle calculations and Bader charge analysis were performed to identify the origin of the new PL peaks. Our findings indicate that oxygen vacancies positioning at different locations of the α-MoO3 lead to the emergence of new absorption peaks within the range of ∼2.2–1.25 eV, which is consistent with our experimental findings. The present study gives insight into exploring the use of ion-irradiated α-MoO3 in optoelectronics applications with tunable properties.

Influence of sintering temperature on structural and optical properties of Cd0.5Cu0.5CrxFe2−xO4 ferrites

Two ferrite series were synthesized. One series has nanosize samples that have been prepared by the co-precipitation method, and the second series has the corresponding bulk samples that have been sintered at 1000 °C for 6 h. X-ray diffraction has been used to estimate the cubic spinel structure of both series. The crystallite size, theoretical density, and porosity of the nanomaterials are larger than those of the bulk materials. HRTEM analysis demonstrated the aggregation of nanoscale samples, including an average particle size of 9–22.5 nm. However, bulk specimens have a limited surface area. The agglomeration of the nanoparticles was seen in TEM images, in which the mean particle size was within the limit of the crystallite size (R) result and ranged from 14 to 20 nm. The appearance of the spinel phase in the samples was validated through Raman spectroscopy. Different cation occupation ratios in either tetrahedral or octahedral sites have been identified to be associated with an observable systematic shift and asymmetric flattening in Raman spectra with a variation in Cr3+ concentration. The optical characterization was performed using the UV/Vis methodology, and the results reveal that the absorption cutoff frequency declines as the chromium content rises. It was also estimated that the optical bandgap averaged 3.6 eV for nanosamples and 4.6 eV for overall bulk materials. The highest photoluminescence emission was seen at wavelengths between λem = 415 and 460 nm. The photoluminescence emission peaks of both bulk and nanoscale materials were red-shifted. These results accurately reflect the corresponding energy gap values for almost the same ranges. Sintering leads to a rise in photoluminescence.

Preparation of GaN/Porous silicon heterojunction photodetector by laser deposition technique

In this work, gallium nitride (GaN) thin film was deposited on porous silicon (PSi) substrate via a pulsed laser deposition route with a 355 nm laser wavelength, 900 mJ of laser energy, and various substrate temperatures raging from 200 to 400 °C. The structural and optical properties of GaN films as a function of substrate temperature are investigate. XRD studies reveal that the GaN films deposited on porous silicon are nanocrystalline with a hexagonal wurtzite structure along (002) plane. The photoluminescence emission peaks of the GaN/PSi prepared at 300 °C substrate temperature are located at 368 nm and 728 nm corresponding to energy gap of 3.36 eV and 1.7 eV, respectively. The GaN/PSi heterojunction photodetector prepared at 300 °C exhibits the maximum performance, with a responsivity of 29.03 AW−1, detectivity of 8.6 × 1012 Jones, and an external quantum efficiency of 97.2% at 370 nm. Similarly, at 575 nm, the responsivity is 19.86 AW−1, detectivity is 8.9 × 1012 Jones, and the external quantum efficiency is 50.89%. Furthermore, the photodetector prepared at a temperature of 300 °C demonstrates a switching characteristic where the rise time and fall time are measured to be 363 and 711 μs, respectively.

Plasma electrochemical synthesis of silicon quantum dots

Environmentally friendly and fast synthesis of silicon quantum dots (SiQDs) is realized with the assistance of plasma. The precursors used are N-(β-aminoethyl)-γ-aminopropyl trimethoxysilane (DAMO) and citric acid. When the excitation wavelength was 370 nm, the photoluminescence emission peak of the SiQDs appeared at 452.5 nm. The optimization of precursor concentration, reaction time and other parameters can effectively improve the quantum yield (QY) of SiQDs. The results show that the amidation and condensation of DAMO and citric acid plays an important role in the improvement of QY, as this means that more fluorescent molecules are produced and therefore QY is increased. This paper increases QY from 4.23% to 23.9%, providing a promising way to improve QY even more.

Fabrication and characterization of novel multifunctional superparamagnetic and fluorescent bioactive glasses for biomedical applications

Magnetic-fluorescent nanosystems have wide applications in the biomedical field due to their dual ability of unique biomolecular fluorescent recognition and magnetic modes. In this study fabrication of superparamagnetic-fluorescent bioactive glasses in the form of particle, nanofiber, and 3D scaffold was performed by the inclusion of maghemite (γ-Fe2O3) nanoparticle and photoluminescent rare earth element ions (Eu3+, Gd3+, and Yb3+). Bioactive glasses in the form of particle, nanofiber, and 3D scaffolds were manufactured using sol-gel, electrospinning, and robocasting techniques, respectively. Morphological, structural, magnetic, and luminescence properties of the fabricated bioactive glasses have been investigated comprehensively using electron microscopy, x-ray diffractometer, vibrating sample magnetometer, Fourier transform infrared, and fluorescence spectrometers. The compressive strength of the robocast 3D glass scaffolds was measured. In vitro hydroxyapatite deposition on the surface of the bioactive glasses soaked in simulated body fluid for various times up to 28 days was also examined. Results showed that all of the bioactive glasses prepared in the study with different morphological characteristics have superparamagnetic properties. Saturation magnetization (Ms) values of the glasses were in the range of 7.20–12.50 emu/g. Additionally, all of the studied glass samples showed fluorescence behavior. The highest photoluminescence emission peak intensity was recorded for the Eu3+-doped robocast 3D glass scaffolds which is followed by nanofibrous and particulate forms of bioactive glass. Results of the in vitro bioactivity experiments showed that hydroxyapatite formation occurred on all of the bioactive glass samples and the highest hydroxyapatite formation rates were obtained for the fibrous glass samples due to their higher surface area.

One-pot synthesis of full-color carbon dots with N, O surface-state energy-gap-controlled emission

An easy and effective route for preparing full-color (blue, green, yellow and red) carbon dots (CDs) with brilliant and stable photoluminescent (PL) was developed by using gallic acid and o-Phenylenediamine as precursors. The resulting CDs were then separated by silica-gel column chromatography. The prepared four types of CDs owned high quantum yields (up to 11.2%) and exhibited attractive features such as excellent solubility, high stability, excitation wavelength-independent PL, mono-exponential PL lifetimes, low cell toxicity and homogeneous optical properties. Then, the mechanism of full-color CDs PL was explored. The results suggested that the surface-states of prepared CDs, especially the pyridine N (C = N) and C = O functional groups, were primarily responsible for the full-color PL emission. The blue CDs had the largest content of C = O while the CDs turned to be green as the C = O decreased and the C = N content increased. The surface state regulation of C = N bond was dominant in yellow CDs while red CDs possessed highest content of C = N and new –COOH appeared. The gradual substitution of C = N to C = O made the band gap of CDs narrowed, which is the main reason for the redshift of CDs PL emission peak. Importantly, the easy preparation and unique optical features of these CDs made them potentially useful in numerous applications such as full-color cell labeling, drug delivery and optoelectronic technologies.

Deep‐Red InP Core‐Multishell Quantum Dots for Highly Bright and Efficient Light‐Emitting Diodes

AbstractInP‐based quantum dots (QDs) are one of the most promising heavy‐metal‐free materials for light‐emitting applications to substitute cadmium‐analogous QDs. With a bulk band gap of 1.35 eV, InP QDs can be made to emit light in the deep red and even near‐infrared region by adjusting the size. Deep‐red light‐emitting diodes (LEDs) are of great interest for promoting the growth of plants and accurate red LED displays. However, the synthesis and the fabrication of InP‐based quantum‐dot LEDs (QLEDs) emitting in the deep red region are still under development. Here, the study reports deep‐red InP/ZnSe/ZnSeS/ZnS core‐shell QDs with a photoluminescence (PL) emission peak at 680 nm and a PL quantum yield up to 95%, which is the highest among reported deep‐red QDs. Multi‐shell with a transition layer of ZnSeS is realized to decrease the lattice mismatch in the shell and increase the shell thickness, which efficiently confines charge carriers and reduces non‐radiative recombinations. In addition, the core‐shell InP QLED achieves a high luminescence of 2263 cd m−2 and an external quantum efficiency up to 6.5%. This report provides a new strategy for promoting the development of deep‐red QLEDs for next‐generation lighting and display devices.

Digitizing protocols into single reactors for the one-pot synthesis of nanomaterials

Digitizing protocols into single reactors for the one-pot synthesis of nanomaterials