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Narrow band red-emitting phosphors based on organo-Eu(III) complexes prove their energetic features with surprising performance in smart red/white LEDs, sensing, and biological fields. In this report, a series of unique Eu(III) complexes have been synthesized with coumarin integrated with a class of phenanthroline(Phen)/thiabendazole(TBZ) based ancillary ligands and dibenzoyl methane (DBM)/2-theonyl trifluoroacetone (TTA) as an anionic ligand. The computational study reveals that the TBZ/Phen-based neutral ligands are superior energy harvesters to those other reported analogue neutral ligands. All the Eu-complexes demonstrated outstanding red emission due to electric dipole (ED) transition (5D0 → 7F2) in solid, solution, and thin film with high quantum yield (QY). Theoretical analysis (TD-DFT) and experimental findings describe that the energy transfer (ET) from the ligand's triplet level to the Eu(III) ion is completely occurring. The Eu(III) complexes can potentially be used to fabricate intense hybrid white and red LEDs. All of the fabricated red LEDs revealed high luminous efficiency of radiation (LER) values. The fabricated blue LED based hybrid white LEDs displayed remarkable performance with a low correlated color temperature (5634 K), high color rendering index 88%, and CIE values (x = 0.33; y = 0.342) for 3Eu. By interaction with acid-base vapors, Eu-complexes displayed effectively alterable on-off-on luminescence. Further, cellular imaging shows that Eu-complexes can be a potential biomarker for cancer cell lines.

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An efficient urea-assisted SC (solution-combustion) approach was used to synthesize a novel series of doped Ca0.5Bi3P2O10: xDy3+ nanophosphors (0.01-0.1 mol). The powdered materials were thoroughly investigated using structural and optical measures. 'Rietveld refinement' investigations found that the produced nanophosphor formed a triclinic system with the P -1 triclinic space group. An EDS (energy-dispersive spectral) study was conducted to determine the corresponding proportions of constituent elements of doped nanophosphors. The TEM (transmission electron microscopy) revealed aggregated particles with a standard size on the nanoscale. The PLE (Photoluminescence excitation) spectrum indicates that the indicated phosphors can be stimulated by NUV (near ultraviolet) illumination sources. The Dy3+-ions undergo transitions from (4F9/2 → 6H15/2 & 4F9/2 → 6H13/2) were recognized as (PL) spectra with an excitation of 353 nm revealed the presence of blue-yellow bands at 481, and 577 nm, correspondingly. Further, PL data was used to determine photometric metrics such as CCT (correlated color-temperature), CC (chromaticity-coordinates (x & y)), and CP (color-purity (%)), supporting their use in solid-state lighting and latent fingerprinting applications.

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Tetrahedron-based nitrides offer a wide range of properties and applications. Highly condensed nitridophosphates are examples of nitrides that exhibit fascinating luminescence properties when doped with Eu2+, making them appealing for industrial applications. Here, we present the first nitridomagnesophosphate solid solution series Ba3-xSrx[Mg2P10N20] : Eu2+ (x=0-3), synthesized by a high-pressure high-temperature approach using the multianvil technique (3 GPa, 1400 °C). Starting from the binary nitrides P3N5 and Mg3N2 and the respective alkaline earth azides, we incorporate Mg into the P/N framework to increase the degree of condensation κ to 0.6, the highest observed value for alkaline earth nitridophosphates. The crystal structure was elucidated by single-crystal X-ray diffraction, powder X-ray diffraction, energy-dispersive X-ray spectroscopy (EDX), and solid-state NMR. DFT calculations were performed on the title compounds and other related highly condensed nitridophosphates to investigate the influence of Mg in the P/N network. Eu2+-doped samples of the solid solution series show a tunable narrow-band emission from cyan to green (492-515 nm), which is attributed to the preferred doping of a single crystallographic site. Experimental confirmation of this assumption was provided by overdoping experiments and STEM-HAADF studies on the series as well on the stoichiometric compound Ba2Eu[Mg2P10N20] with additional atomic resolution energy-dispersive X-ray spectroscopy (EDX) mapping.

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Energy-efficient white light-emitting diodes (LEDs) are in high demand across the society. Despite the significant advancements in the modern lighting industry based on solid-state electronics and inorganic phosphor, solid-state lighting (SSL) continues to pursue improved efficiency, saturated color performance, and longer lifetime. Here in this article, robust, narrow emission band nanorods (NRs) are disclosed with tailored wavelengths, aiming to enhance the color rendering index (CRI) and luminous efficacy (LE). The fabricated lighting device consists of NRs of configuration CdSe/ZnxCd1-xS/ZnS, which can independently tune CRI R1-R9 values and maximize the luminous efficacy. For general lighting, NRs with quantum yield (QY) up to 96% and 99% are developed, resulting in ultra-efficient LEDs reaching a record high luminous efficacy of 214 lm W-1 (certified by the National Accreditation Service). Furthermore, NRs are deployed onto mid-power (0.3 W@ 50 mA) LEDs, showing significantly enhanced long-term stability (T95 = 400 h @ 50 mA). With these astonishing properties, the proposed NRs can pave the way for efficient lighting with desired optical spectrum.

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Low-dimensional metal halides with broadband emissions are expected to serve as downconversion luminescent materials for solid-state lighting (SSL). However, efficiently generating full-spectrum white-light emission with a high color-rendering index (CRI) in single-phase emitters remains a challenge. Here, we report a novel zero-dimensional (0D) hybrid mixed-metal halide (TPA)2CuAgI4 (TPA = tetrapropylammonium), in which individual [CuAgI4]2- dimers are completely isolated and surrounded by the organic cations TPA+. Cu+ and Ag+ share the same crystallographic site in [CuAgI4]2- dimers with the same statistical probability. Upon photoexcitation, single crystals exhibit a full-spectrum white-light emission with a full width at half-maximum (fwhm) of up to 314 nm and a high quantum efficiency of 46.8%. Detailed photophysical studies and theoretical calculations reveal that the ultra-broadband emission of (TPA)2CuAgI4 originates from the radiative recombination of red-, green-, and blue-emitting self-trapped excitons in [CuAgI4]2- dimers. In addition, (TPA)2CuAgI4 nanocrystals were successfully synthesized and exhibited optical properties similar to those of single-crystal counterparts. Finally, a prototype ultraviolet (UV)-pumped white-light-emitting diode (WLED) and a composite thin film employing this new white-light emitter produces a well-distributed full-spectrum white light with a high CRI of 91.4 and a warm correlated color temperature (CCT) of 4135 K, indicating the potential application of this white-light emitter in SSL. These results provide a new perspective for designing superior single-phase white-light emitters.

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The present study investigates the impact of the ligand environment on the luminescence and thermometric behavior of Sm3+ doped A3 (PO4 )2 (A = Sr, Ca) phosphors prepared by combustion synthesis. The structural and luminescent properties of Sm3+ ions in the phosphate lattices were investigated using powder X-ray diffraction (PXRD) and photoluminescence (PL) techniques. PXRD results of the synthesized phosphors exhibit the expected phases that are in agreement with their respective standards. Fourier-transform infrared (FTIR) spectroscopy confirms the presence of PO4 vibrational bands. Upon excitation with near ultraviolet light, the PL studies indicated that Sr3 (PO4 )2 :Sm3+ phosphors exhibit a yellow light emission, whereas Ca3 (PO4 )2 :Sm3+ phosphors exhibit an emission of orange light. The PL emission results are in accordance with the CIE coordinates, with the Sr3 (PO4 )2 :Sm3+ phosphors showing coordinates of (0.56, 0.44), and the Ca3 (PO4 )2 :Sm3+ phosphors displaying coordinates of (0.60, 0.40). Thermal analysis shows improved stability of Ca3 (PO4 )2 :Sm3+ based on lower weight reduction in thermogravimetric analysis. The effect of temperature on the luminescence properties of the phosphor has been examined upon a 405 nm excitation. By using the fluorescence intensity ratio (FIR) method, the temperature responses of the emission ratios from the Sm3+ : the 4 F3/2 → 6 H5/2 transition to the 4 G5/2 → 6 H7/2 and 4 F3/2 → 6 H5/2 transition to the 4 G5/2 → 6 H9/2 emissions are characterized. The Ca3 (PO4 )2 :Sm3+ phosphors are more sensitive as compared with the Sr3 (PO4 )2 :Sm3+ phosphors. The earlier research findings strongly indicate that these phosphors hold great promise as ideal candidates for applications in non-invasive optical thermometry and solid-state lighting devices.

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Solid-state light-emitting diodes (LEDs) emit nearly monochromatic light, yet seamless tuning of emission color throughout the visible region remains elusive. Color-converting powder phosphors are therefore used for making LEDs with a bespoke emission spectrum, yet broad emission lines and low absorption coefficients compromise the formation of small-footprint monochromatic LEDs. Color conversion by quantum dots (QDs) can address these issues, but high-performance monochromatic LEDs made using QDs free of restricted, hazardous elements remain to be demonstrated. Here, we show green, amber, and red LEDs formed using InP-based QDs as on-chip color convertor for blue LEDs. Implementing QDs with near-unity photoluminescence efficiency yields a color conversion efficiency over 50% with little intensity roll-off and nearly complete blue light rejection. Moreover, as the conversion efficiency is mostly limited by package losses, we conclude that on-chip color conversion using InP-based QDs can provide spectrum-on-demand LEDs, including monochromatic LEDs that bridge the green gap.

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Multifunctional phosphors have significant application and scientific value and are becoming a research hotspot in the field of luminescent materials. Herein, we report Mn4+-activated double-perovskite-type Sr2LuNbO6 multifunctional phosphors with excellent comprehensive properties in the fields of optical temperature/pressure sensing and w-LED lighting. The crystalline structure, elemental composition, optimal doping concentration, crystal-field strength, and optical bandgap of the phosphors are investigated in detail, and the mechanisms of concentration and thermal quenching are discussed. From the optimal Sr2LuNb0.998O6:0.2%Mn4+ phosphor, a LED lamp for indoor warm-white lighting is successfully fabricated. Further, the thermometric properties of the phosphors are explored for applications as FIR- and lifetime-based thermometers, showing a maximum relative sensitivity of 1.55% K-1 at 519 K. Upon pressure loading, a significant red-shift of the peak centroid is observed, and the pressure sensitivity is determined to be 0.82 nm/GPa. These results suggest that the Mn4+-activated Sr2LuNbO6 multifunctional phosphors have great potential to be utilized in the fields of optical thermometry, manometry, and lighting.

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A series of Ca9Gd(VO4)7: Dy3+ (x = 0.01-0.20) nanophosphor crystals emitting a cool white light were synthesized by solution combustion methodology. The X-ray diffraction patterns were analyzed and processed using Rietveld refinement. The fabricated nanophosphor was found to crystallize in a trigonal crystal lattice with space group R3c(161). The morphological behavior of the prepared nanophosphor was investigated using transmission electron microscopy (TEM) and scanning electron microscopy (SEM). The photoluminescence properties of the nanophosphor correspond to cool white emission upon near-ultraviolet (NUV) excitation at 327 nm due to 4F9/2 → 6H15/2 (bluish) and 4F9/2 → 6H13/2 (yellowish) radiative relaxations at 487 nm and 576 nm respectively. Also, there is a strong occurrence of double charge transfer from O2- ions to Dy3+ and V5+ ions with the latter being stronger due to the high positive charge of V5+ ions. Color coordinates (x = 0.2878, y = 0.3259) are consistent with white emission. Auzel's model was implemented to examine the non-radiative relaxation (113.5 ms-1), radiative lifetime (1.4856 ms), and quantum efficiency (83.13%) values. The crystalline and optical behavior of the synthesized cool white emitting nanophosphor facilitates its use in near-UV-based WLEDs and other advanced solid-state lighting.

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While junction temperature control is an indispensable part of having reliable solid-state lighting, there is no direct method to measure its quantity. Among various methods, temperature-sensitive optical parameter-based junction temperature measurement techniques have been used in practice. Researchers calibrate different spectral power distribution behaviors to a specific temperature and then use that to predict the junction temperature. White light in white LEDs is composed of blue chip emission and down-converted emission from photoluminescent particles, each with its own behavior at different temperatures. These two emissions can be combined in an unlimited number of ways to produce diverse white colors at different brightness levels. The shape of the spectral power distribution can, in essence, be compressed into a correlated color temperature (CCT). The intensity level of the spectral power distribution can be inferred from the luminous flux as it is the special weighted integration of the spectral power distribution. This paper demonstrates that knowing the color characteristics and power level provide enough information for possible regressor trainings to predict any white LED junction temperature. A database from manufacturer datasheets is utilized to develop four machine learning-based models, viz., k-Nearest Neighbor (KNN), Radius Near Neighbors (RNN), Random Forest (RF), and Extreme Gradient Booster (XGB). The models were used to predict the junction temperatures from a set of dynamic opto-thermal measurements. This study shows that machine learning algorithms can be employed as reliable novel prediction tools for junction temperature estimation, particularly where measuring equipment limitations exist, as in wafer-level probing or phosphor-coated chips.

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The need of new materials with desirable optical properties has become important in recent years. In particular, a need has emerged for compounds having better luminescence properties in various practical applications. The introduction of rare earth ions as activators improves the luminescence properties of the compounds considerably. Boron is one of the most abundant elements in nature. It readily combines with almost all other elements. In combination with oxygen; it forms borates comprised of various anions such as BO3 3- , B2 O5 4- , etc. Apart from these simple borates, several complex compositions exist involving mixed anions as well as double metal borates, due to the three-fold, or four-fold coordination of borate atoms. Borates intrinsically possesses characteristics that are advantageous for optical materials, which include a wide transparency range, large electronic band gap, good thermal and chemical stability, low preparative temperature, optical stability with good nonlinear characteristics, and an exceptionally high optical damage threshold. The unique crystal structure of borates determines their enhanced ultraviolet light transparency, good nonlinearity, and relatively high resistance against laser-induced damage. Some of these complex borates have interesting luminescence properties that are covered in this review. These include double borates containing rare earths RM3 (BO3 )4 , pentaborates LaMgB5 O10 , M3 R2 (BO3 )4 , where M is an alkaline earth, mixed anion borates such as aluminoborate SrAl2 B2 O7 , silicate-borates such as pekovite, SrB2 Si2 O8 , haloborates, M2 B5 O9 X, where M is an alkaline earth and X is a halogen, phosphate borates, and MBPO5 , where M is an alkaline earth. Phosphors based on these compositions find use in various applications such as fluorescence lamps, colour TVs, plasma display panels, high-intensity discharge lamps based on xenon, optically pumped solid-state lasers, eye-safe lasers, and X-ray imaging.

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Trivalent dysprosium/europium-codoped silicate phosphors (Ba1.3Ca0.7x-ySiO4:xDy3+/yEu3+) were prepared as a function of Eu3+concentration (x= 0.03 andy= 0.01-0.05). The phosphors showed the averaged crystallite size of ∼37.2 ± 1.3 nm and displayed nano-/micro-scale grains with some void defects. The energy bandgap is about 4.3 eV for co-doped samples and 3.2 eV for the silicate host. The photoluminescence spectra indicated that the presence of Eu3+ions enhanced the red light emission, and the emission peaks located at the versatile wavelengths of 482, 577, 592, 614, 652, and 703 nm. Then, the internal quantum efficiencies were estimated by using the Judd-Ofelt model. Resultantly, the best quantum efficiency was ∼74% when the doping concentrations were 3 mol% Dy3+and 4 mol% Eu3+ions. Finally, the CIE coordinate data exhibited that the emission color could be tuned from white to reddish-orange by changing the Eu3+contents, proposing the applicability of Ba1.3Ca0.7-x-ySiO4:xDy3+/yEu3+phosphors to the solid-state lighting.

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Solid-state lighting (SSL) sources based on light-emitting diodes represent the new generation of highly efficient illumination systems that significantly impact energy-saving. The development of white light-emitting diodes (WLEDs) with a combination of high color rendering index (CRI) and high deep-red color rendering R9 is an important challenge in the field of solid-state lighting. On the other hand, most WLEDs use rare-earth inorganic luminescent materials. The annual demand for rare-earth metals has doubled to 125,000 tons in 15 years, and the demand is projected to reach 315,000 tons in 2030. The explosion in demand for these materials, combined with a monopolistic supply source, represents a real risk for the development of WLEDs in the next few years. Luminescent organic materials are a relevant and promising alternative. Here, we report a WLED with a very high CRI of 95.7 and R9 of 78.7, obtained using a combination of a blue LED chip (excitation source) and two organic luminescent dyes (Coumarin 6 and Lumogen Red) acting as spectral converters in a multilayer remote phosphor configuration. To the best of our knowledge, this is the first rare-earth-free WLED with such high values of CRI and R9.

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GaN-based µLEDs with superior properties have enabled outstanding achievements in emerging micro-display, high-quality illumination, and communication applications, especially white-light visible light communication (WL-VLC). WL-VLC systems can simultaneously provide white-light solid-state lighting (SSL) while realizing high-speed wireless optical communication. However, the bandwidth of conventional white-light LEDs is limited by the long-lifetime yellow yttrium aluminum garnet (YAG) phosphor, which restricts the available communication performance. In this paper, white-light GaN-µLEDs combining blue InGaN-µLEDs with green/red perovskite quantum dots (PQDs) are proposed and experimentally demonstrated. Green PQDs (G-PQDs) and red PQDs (R-PQDs) with narrow emission spectrum and short fluorescence lifetime as color converters instead of the conventional slow-response YAG phosphor are mixed with high-bandwidth blue InGaN-µLEDs to generate white light. The communication and illumination performances of the WL-VLC system based on the white-light GaN-based µLEDs are systematically investigated. The VLC properties of monochromatic light (green/red) from G-PQDs or R-PQDs are studied in order to optimize the performance of the white light. The modulation bandwidths of blue InGaN-µLEDs, G-PQDs, and R-PQDs are up to 162 MHz, 64 MHz, and 90 MHz respectively. Furthermore, the white-light bandwidth of 57.5 MHz and the Commission Internationale de L'Eclairage (CIE) of (0.3327, 0.3114) for the WL-VLC system are achieved successfully. These results demonstrate the great potential and the direction of the white-light GaN-µLEDs with PQDs as color converters to be applied for VLC and SSL simultaneously. Meanwhile, these results contribute to the implementation of full-color micro-displays based on µLEDs with high-quality PQDs as color-conversion materials.

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Phosphor-containing white light-emitting diodes (LEDs) with low color-correlated temperatures (CCTs) and high color rendering indexes (CRIs) are highly desirable for energy-efficient and environmentally friendly solid-state light sources. Here, we report a new and efficient blue light-excited, green-emitting Ce3+-activated CaY2ZrScAl3O12 phosphor, which underpins the fabrication of high-color quality and full-visible-spectrum warm-white LED devices with ultrahigh CRI values (Ra > 96 and R9 > 96). A family of CaY2ZrScAl3O12:Ce3+ phosphors with different Ce3+ dopant concentrations were prepared by high-temperature solid-state synthesis. X-ray diffraction and corresponding Rietveld refinement reveal a garnet structure with an Ia3̅d space group and crystallographic parameters a = b = c = 12.39645(8) Å, α = ß = γ = 90°, and V = 1904.99(4) Å3. Luminescence properties were studied in detail as a function of Ce3+ with the optimal concentration 1% mol. Impressively, CaY2ZrScAl3O12:1%Ce3+ exhibits a broad excitation band from 370 to 500 nm, peaking at ∼421 nm, which is well matched with emission from commercial blue LED chips. Under 421 nm excitation, the CaY2ZrScAl3O12:1%Ce3+ phosphor produces dazzling green light in a wide emission band from 435 to 750 nm (emission peak: 514 nm; full width at half-maximum: 113 nm), with a high internal quantum efficiency of 63.1% and good resistance to thermal quenching (activation energy of 0.28 eV). A white LED device combining a 450 nm blue LED chip with CaY2ZrScAl3O12:1%Ce3+ green phosphor and commercial CaAlSiN3:Eu2+ red phosphor as color converters demonstrates bright warm-white light with excellent CIE color coordinates of (0.3938, 0.3819), low CCT of 3696 K, high CRI (Ra = 96.9, R9 = 98.2), and high luminous efficacy of 45.04 lm W-1 under a 20 mA driving current. New green phosphors enable the design and implementation of efficient luminescent materials for healthy solid-state lighting.

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We have synthesized sulfonamide based nano-composites of SiO2 and TiO2 for selective and sensitive determination of toxic metal ion Hg2+ in aqueous medium. Nano-composites (11) and (12) were morphologically characterized with FT-IR, solid state NMR, UV-vis, FE SEM, TEM, EDX, BET, pXRD and elemental analysis. The comparative sensing behavior, pH effect and sensor concentrations were carried out with fluorescence signaling on spectrofluorometer and nano-composites (11) and (12), both were evaluated as "turn-on" fluorescence detector for the toxic Hg2+ ions. The LODs were calculated to be 41.2 and 18.8 nM, respectively of nano-composites (11) and (12). The detection limit of TiO2 based nano-composites was found comparatively lower than the SiO2 based nano-composites.

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Cesium lead halide perovskite nanocrystals have recently become emerging materials for color conversion in visible light communication (VLC) and solid-state lighting (SSL), due to their fast response and desirable optical properties. Herein, perovskite nanocrystal-polymethyl methacrylate (PNC-PMMA) films with red and yellow emission are prepared. The PNC-PMMA films, with optical properties such as a short lifetime and air stability, are used to make broadband color converters based on a high-bandwidth 75 µm blue micro-LED (µLED) for VLC. The yellow-emitting CsPb(Br/I)3 PNC-PMMA has a high bandwidth of 347 MHz, while the red-emitting CsPbI3 PNC-PMMA exhibits a higher modulation bandwidth of 822 MHz, which is ∼65 times larger than that of conventional phosphors. After fixing the two PNC-PMMA films in front of the µLED, a qualified warm white light is generated with a correlated color temperature of 5670 K, a color rendering index of 75.7, and a de L'Eclairage (CIE) coordinate at (0.33, 0.35). Although the color conversion of the blue light sacrifices some received power and slightly reduces the overall bandwidth from 1.130 to 1.005 GHz, a maximum real-time data rate of 1.7 Gbps is still achievable using the non-return-to-zero on-off keying modulation scheme, which is ∼6 times higher than that of the previous record. This study provides a practical approach to develop a considerably high-bandwidth white-light system for both high-speed VLC and high-quality SSL.

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Nowadays, solid-state white light-emitting diodes (wLEDs) have attracted remarkable attention for applications in general lighting, displays and numerous electronical devices due to their eminent efficiency, longer lifetime and higher mechanical durability compared to traditional incandescent and fluorescent lights. In current commercial wLEDs, a combination of Y3Al5O12:Ce3+yellow phosphor with blue LED chip and epoxy resin is generally used to generate white light. However, there are some considerable frailties mostly originated from phosphor and resin such as, degradation upon heat, and moisture, inhomogeneous spectral distribution, and poor color rendering capability. Therefore, phosphor embedded glass-ceramics have been developed as a promising way to obtain durable solid-state lighting devices. However, in these methods, there is a greater risk of reactions between the phosphor material and the glass host. At this point, lanthanide-doped luminescent glasses have drawn great attention as a new generation phosphor and/or epoxy free white-light-emitting source owing to their favorable properties including high thermal and chemical stability, high transparency, and easy manufacturing process. This review article aims to comprehensively summarize the recent progress in singly (i.e., Dy3+, Eu2+), doubly (i.e., Dy3+/Eu3+, Dy3+/Tm3+, Dy3+/Ce3+, Ce3+/Sm3+, Ce3+/Tb3+) and triply (i.e., Ce3+/Tb3+/Mn2+, Eu3+/Tb3+/Tm3+, Ce3+/Tb3+/Eu3+, Tm3+/Tb3+/Sm3+, Ce3+/Dy3+/Eu3+, Ho3+/Tm3+/Yb3+, Er3+/Tm3+/Yb3+) lanthanide-doped glasses for solid-state lighting applications through down-shifting and up-conversion emissions. Theoretical background including energy transfer mechanisms, glass synthesis methods, radiative and colorimetric properties are given in details. Finally, various effective strategies are highlighted that minimize the critical challenges associated with lanthanides-such as providing energy transfer from quantum dots or nanoparticles to lanthanides, and doping lanthanides in low phonon energy glass-to improve the white light emission of luminescent glasses and broaden their application areas.

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White-light-emissive organic micro/nanostructures hold exotic potential applications in full-color displays, on-chip wavelength-division multiplexing, and backlights of portable display devices, but are rarely realized in organic core/shell heterostructures. Herein, through regulating the noncovalent interactions between organic semiconductor molecules, a hierarchical self-assembly approach of horizontal epitaxial-growth is demonstrated for the fine synthesis of organic core/mono-shell microwires with multicolor emission (red-green, red-blue, and green-blue) and especially organic core/double-shell microwires with radial red-green-blue (RGB) emission, whose components are dibenzo[g,p]chrysene (DgpC)-based charge-transfer (CT) complexes. In fact, the desired lattice mismatching (≈2%) and the excellent structure compatibility of these CT complexes facilitate the epitaxial-growth process for the facile synthesis of organic core/shell microwires. With the RGB-emissive substructures, these core/double-shell organic microwires are microscale white-light sources (CIE [0.34, 0.36]). Besides, the white-emissive core/double-shell microwires demonstrate the fascinating full-spectrum light transportation from 400 to 700 nm. This work indeed opens up a novel avenue for the accurate construction of organic core/shell heterostructures, which provides an attractive platform for the organic integrated optoelectronics.

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Precession electron diffraction (PED) was used to measure the long-range order parameter in lattice-mismatched AlInP epitaxial films under investigation for solid-state-lighting applications. Both double- and single-variant films grown at 620, 650 and 680 °C were analysed in TEM cross-section. PED patterns were acquired in selected-area-diffraction mode through external microscope control using serial acquisition, which allows inline image processing. The integrated peak intensities from experimental patterns were fit using dynamical simulations of diffraction from the ordered domain structures. Included in the structure-factor calculations were mean atomic displacements of the anions (P) due to ordering, which were found by valence-force-field calculations to have a nearly linear dependence on order parameter. A maximum order parameter of S = 0.36 was measured for a double-variant specimen grown at 650 °C.

Compound semiconductors play a central role in current light-emitting diodes (LED) technology, but improvements in the red- and amber-emitting components are needed. The semiconductor alloy AlInP offers advantages over incumbent materials by making use of an arrangement in the crystal structure, called 'atomic ordering', that occurs spontaneously under certain deposition conditions. Quantitative measurement of the extent to which the ordering phenomenon occurs is needed to fully exploit the properties of the ordered material. Transmission electron diffraction offers a means to directly probe the ordered structures, but the quantification of electron-diffraction data has been a long-standing challenge, due to multiple scattering processes, referred to as 'dynamical' diffraction. The method of precession electron diffraction (PED) addresses this problem and has found numerous applications in crystallography. We have applied PED to ordered AlInP films, using computer-controlled acquisition to perform alignments and construct data sets during collection. A model of the microscopic, ordered domain structure was developed to compare the diffraction data to simulations. Samples grown at different temperatures, and ordered along either one or two directions, were evaluated. The strongest ordering was observed in a sample grown at 650 °C with ordering along two directions.