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We report the enhanced photothermal stability of in situ grown FAPbBr3 perovskite nanocrystals in polyvinylidene fluoride by incorporation of Cd2+ ions, which have potential applications in backlight devices.

Mn-doped perovskite nanocrystals have promised new optoelectronic applications due to their unique material properties. In the present study, Mn-doped perovskite nanocrystalline films were prepared in situ in a polymer matrix. The Mn-doped perovskite nanocrystals (PNCs) had good crystallinity and uniform size/spatial distributions in the polymer film. Bright dual-color emission and the long lifetime of the excited state of the dopant were observed from the host exciton and the Mn2+ dopant, respectively. Furthermore, magnetism was observed in the optimal Mn2+ concentration, implying that magnetic coupling was achieved in the Mn-doped perovskite lattice. The Mn-doped perovskite films also showed superior stability against moisture. To demonstrate the practicality of this composite film, a white light emitting device was fabricated by combining a single composite film with a blue light emitting diode; the device showed a high-quality white light emission, and the Commission Internationale De L'Eclairage (CIE) chromaticity coordinate of the white light emitting diode (WLED) (0.361, 0.326) was close to the optimal white color index. In this single-layer WLED, self-absorption among the luminous multilayers in traditional white light emitting diodes can be avoided. The study findings revealed that Mn-doped perovskite nanocrystalline films have many exciting properties, which bodes well for the fundamental study and design of high-performance optoelectronic devices.

A p-type semiconductor candidate of nickel oxide (NiO) desires longer carrier lifetimes with suitable conduction band edge, which holds a unique advantage to drive the hydrogen evolution toward eff...

Lead-free double perovskites are emerging as an excellent candidate material for optoelectronic devices, owing to their unique properties such as widely adjustable band gap and markedly lower toxicity than the lead-halide counterparts. In this work, a series of Mn2+-doped Cs2NaInCl6 (Mn2+:Cs2NaInCl6) DP crystals with tailored Mn2+-doping concentrations are synthesized. The effects of the reaction temperatures and Mn/(In + Na) ratios in the raw materials on the Mn2+ doping concentrations and their photoluminescence (PL) properties are investigated systematically. The resultant DP crystals exhibit well-resolved Mn2+ 4T1 → 6A1 d − d emission with an optimal PL quantum yield of 16% and an extremely long excited state lifetime up to ~ 17 ms, which is the longest one of Mn2+ emission among those of Mn2+-doped II–VI semiconductors or perovskite materials ever reported. Furthermore, the temperature-dependent PL and PL decay are studied in the temperatures range from 120 to 480 K. The decay lifetime decreased monotonously with the rise in temperatures, while the PL intensity gradually reaches a maximum and then keeps nearly constant, followed by a sharp decrease. Such abnormal phenomenon is mainly attributed to the combined effect of intrinsic property of octahedrally coordinated Mn2+ in perovskite lattice and enhanced electron–phonon coupling at elevated temperature.

This paper explores the pros and cons of different algorithm models on the same selection problem, and then uses the combined prediction theory to obtain a new combined prediction model to explore its prediction accuracy. The actual problem to be solved is to help financial institutions to scientifically classify customers who choose financial products. We select the bank data set in the UCI database, which is derived from the survey data of a customer conducted by a financial institution in Portugal for a wealth management product. Decision tree C5.0 algorithm, naive Bayes classification algorithm and binary logit model are individually used to carry out a single model of empirical research on financial product customer classification. Through the empirical analysis of the five combination models, it is concluded that in the model that uses the least squares weighting method to determine the weight, the weight appears negative, which does not conform to the actual situation. The model that is based on the least squares weighting method and the model that is based on the simple weighting method are excluded. In contrast, the arithmetic mean weighted model is better than the reciprocal variance weighted model and the reciprocal mean square model. The accuracy reaches 89.91%, which is 0.43% higher than the accuracy of a single model. It can be concluded that the model that is based on the arithmetic average weighting is a better combination forecasting model.

Recently, lead-free double perovskites of Cs2AgBiBr6 have attracted worldwide attention as a promising candidate for eco-friendly photovoltaics because of their intrinsic environmental stability and highly desired low toxicity in comparison with conventional lead halide counterparts. However, their power conversion efficiency (PCE) is still far lower than that of lead halide perovskites, which is mainly associated with their poor quality films. Herein, we report a facile process via precursor engineering based on the BiBr3(DMSO)2 adduct solution to produce high-coverage and smooth Cs2AgBiBr6 films with large grains. As a result, the as-constructed planar solar cells deliver a champion PCE of 0.73%, which exhibits an enhancement of over 40% in PCE compared to that of the control sample, suggesting their potential to be applied in lead-free bismuth-based optoelectronic devices.

In the present work, we report a strategy for aligned packaging of in situ grown CsPbBr3 nanorods (NRs) within polystyrene (PS) nanofibers (CsPbBr3 NR@PS) based on magnetic field assisted electrospinning for enhanced polarized luminescence properties. The as-constructed CsPbBr3 NR@PS fiber membrane exhibits an improved orientation and increased aspect ratio (AR) of the aligned CsPbBr3 NRs within the PS fibers with the increase of the external magnetic field strength. Consequently, their luminescence polarization ratio (P) can be fundamentally enhanced with the increase of the external magnetic field strength. The P of the sample prepared at a magnetic field of 150 mT reaches 0.23, which is 2.6 times that of the conventional analogue fabricated without a magnetic field, and close to the theoretical emission polarization one (Pem-theory), representing their potential applications in optical devices such as liquid crystal displays.

Currently, the exploration of green tin halide perovskite solar cells (PSCs) based on orthorhombic (γ-) CsSnI3 is fundamentally hindered by its intrinsic bad stability. Herein, based on the first principles calculation, three surface-ligand-passivated configurations having inter-molecular hydrogen bonds are rationally designed and investigated for stabilizing γ-CsSnI3. It is discovered that the inter-molecular hydrogen bond could suppress the distortions of both ligands and the octahedral of perovskites, thus favoring improvement in the stability of γ-CsSnI3, which is closely related to bond strength. Moreover, the existing inter-molecular hydrogen bond could limit the localization of charge density, which helps promote electron transition and mobility with optimized carrier effective masses, thus favoring an enhanced performance of γ-CsSnI3 PSCs. The present work might give some insight on pushing forward the strategy of surface ligand passivation for engineering stabilized γ-CsSnI3 PSCs with high efficiency.

The growth of one-dimensional nanostructured semiconductors with aligned configuration and tunable aspect rations is recognized as one of the critically important and fundamental issues, for exploring polarized light sources as the back lights in liquid crystal display (LCD) with desired optical performance. In the present work, aiming to endow the perovskite nanocrystals (NCs) with enhanced stability and polarized optical performance, we reported the in situ growth of aligned CsPbBr3 nanorods in polystyrene (PS) fibers, which was based on a facile one-step electrospinning technique. It was found that the electrospinning temperatures could have a profound effect on the growth of CsPbBr3 nanorods with various aspect ratios (ARs), enabling their growth in a tailored manner. The mechanism on the tunable growth of aligned CsPbBr3 nanorods in PS fibers was proposed.

Hollow carbon nanofibers with hierarchical porous shells were prepared by NaOH activation of the electrospinning SiCNO fibers, followed by carbonization treatment. By adjusting the carbonization temperature, porous hollow carbon nanofibers with different Brunauer-Emmett-Teller (BET) specific surface areas and total pore volumes are obtained, both of which are explored as electrode materials for supercapacitors. It was found that the obtained products (HCF800) possess the highest BET specific surface area of 2628.10 m

Silicon carbide (SiC) is recognized as one of the most important candidates of third generation semiconductors with totally superior physical/chemical properties and exciting applications in opto/electronic devices. In the present work, we report the exploration of high-performance blue-light photodetectors on both rigid and flexible substrates by using SiC nanoarrays, which are aligned by dielectrophoresis. The rise and decay times of the photodetector assembled on a rigid (i.e., SiO2/Si) substrate are ∼0.39 and 0.56 s, respectively, with an external quantum efficiency of 3394%, which suggested that the SiC nanoarray photodetector has high sensitivity, fast responsivity and excellent reproducibility to light irradiation with a wavelength of 445 nm. Meanwhile, 73% of the maximum photocurrent response can be maintained after 6 months. Furthermore, the as-constructed flexible photodetector based on the polyethylene terepthalate (PET) substrate was highly stable against repeated bending, demonstrating that the as-constructed SiC photodetector was robust with high flexibility and electrical stability.

In the present study, the field emission (FE) behaviors of CsPbI3 nanobelts were reported, which were synthesized via a one-step facile solvothermal method. The obtained CsPbI3 nanobelts were single crystalline in nature with a typical growth direction along [100]. It was disclosed that the valence band maximum (VBM) and conduction band minimum (CBM) vs. vacuum level of the CsPbI3 nanobelts were located at −4.86 and −2.16 eV, respectively, and their work function (Φ) was calculated to be of 3.56 eV. The as-grown CsPbI3 nanobelts exhibited outstanding field emission (FE) characteristics with a low turn-on field (Eto) of ∼2.62 V μm−1 and a high field enhancement factor of 3553, representing their potential applications in field emission display devices.

Inorganic perovskites (IP) CsPbX3 (X = Cl, Br, I) have rapidly emerged as excellent candidate materials for optoelectronic devices due to their superior optical/electronic performances. However, poor stability related to their intrinsic ionic character significantly limits their practical applications. Here, a coaxial electrospinning strategy was reported for in situ growth of IP nanocrystals (NCs) in polymer fibers with core/shell structure. The said strategy was based on one-step electrospinning of core solutions containing IP precursors and polymers while the shell solutions containing polymers only contributed to the coaxial structure. The NCs moving in/out of the surface of the core were encapsulated by the shell layer. Compared with the traditional CsPbBr3@polymer fibers without the shell layer, the obtained coaxial fibers exhibited fundamentally improved water stabilities. Their PL quantum yield (QY) retained >90% of its original value after being immersed in water for 10 days and maintained at >84% after 180 days.

The tunable dual-color emitting Mn2+ doped CsPbCl3-xBrx nanocrystals (NCs) with near-unity photoluminescence quantum yield (PL QY) were synthesized through post-treatment of metal bromide at room temperature for fabrication of efficient warm white light-emitting diodes (WLEDs). Especially, the CdBr2 treated blue-orange emitting Mn doped NCs with various Mn/Pb molar feed ratios exhibit higher PL QY of 97% and longer Mn2+ PL lifetime of 0.9 ms. It is surprisingly found that the X-ray diffraction peak at 31.9° is almost not changed with increasing Br composition, meaning formation of metal alloying due to incorporation of amount of divalent cation in NCs. The strong and stable Mn2+ PL at temperature ranging from 80 K to 360 K are revealed and the temperature-dependent energy transfer efficiencies in Mn2+ doped CsPbCl1.5Br1.5 NCs are obtained. The enhancement mechanism of Mn2+ PL QY was attributed to improved energy transfer from exciton to Mn2+ d–d transition and suppressed defect state density after post-treatment. The efficient warm WLEDs with color rendering index of 90 and luminous efficacy of 92 lm/W at 10 mA were fabricated by combining blue-orange dual-emitting Mn2+ doped CsPbCl3-xBrx@SiO2 and green emissive CsPbBr3@SiO2 NCs with violet GaN chips.

Recently, regardless of numerous works reporting on the instability of metal-halide perovskites against humidity/oxygen/heat, another intrinsic weakness under high-energy electron-beam (e-beam) irradiation has emerged. Here, e-beam irradiation-hard perovskite nanocrystals (NCs) are reported, which are based on a doping strategy. The lifetime of Mn2+-doped perovskite NCs under e-beam irradiation at a high acceleration voltage of 200 keV is 10-fold prolonged, in comparison to that of their undoped counterpart. It is discovered that the stronger Mn–Cl and Pb–Cl bonds triggered by Mn2+ doping provide an enhanced chemical stability to the perovskite NCs. Furthermore, the enlarged tolerance factor of the NCs with Mn2+ dopants improves the phase stability of the perovskites. Consequently, both enhanced chemical and phase stabilities offer a more negative formation energy for perovskite NCs with fundamentally increased stability under e-beam irradiation. The present work offers a new route towards irradiation-hard perovskite nanomaterials.

The microstructure evolution of FeCuNbSiB amorphous alloys during stress nanocrystallization has been investigated by in situ synchrotron XRD and ex situ TEM. It is found that the average grain sizes in the stress-annealed samples (SA) and without stress (FA) are 8.6 nm and 10.9 nm, respectively. The volume fraction of the α-Fe(Si) phase increases from 7% to 64% for the SA sample and from 1% to 62% for the FA sample after the soaking stage of the annealing process. The grain size also decreases with increasing tensile stress for the different stress-annealed samples. These results reveal that the tensile stress during annealing reduces Gibbs free energy which promotes nucleation rate, resulting in significantly smaller crystallite sizes.

Molybdenum disulfide (2H-MoS2) based low-dimensional nanostructure materials have great potential for applications in electronic and optoelectronic devices. However, some of the properties such as the origin of the native n-type electrical conductivity (EC) observed in these materials still remain elusive. Here, the defect properties in the 2H-MoS2 bulk system are systematically investigated by first-principles calculation to address these issues. We find that the S vacancy VS with low formation energy cannot be the origin of n-type EC owing to its deep defect levels within the valence band region. All other donor defects such as antisite MoS or Mo interstitial MoI also have deep levels that can trap electrons leading to depressed EC. SMo and SI could be the origin of the p-type EC in 2H-MoS2, but the concentrations are expected to be rather low due to their high formation energies and can only be enhanced under S-rich/Mo-poor conditions. These results provide the underlying insights on the defect properties 2H-MoS2 and explain well the experimental observations.

Currently, all-inorganic CsPbX3 (X = Br, I, Cl) perovskite nanocrystals (NCs) are shining stars with exciting potential applications in optoelectronic devices such as solar cells, light-emitting diodes, lasers, and photodetectors, due to their superior performance in comparison to their organic–inorganic hybrid counterparts. In the present work, we report a general strategy based on a microwave technique for the rapid production of low-dimensional all-inorganic CsPbBr3 perovskite NCs with tunable morphologies within minutes. The effect of the key parameters such as the introduced ligands, solvents, and PbBr2 precursors and microwave powers as well as the irradiation times on the production of perovskite NCs was systematically investigated, which allowed their growth with tunable dimensionalities and sizes. As a proof of concept, the ratio of OA to OAm as well as the concentration of PbBr2 precursor played important roles in triggering the anisotropic growth of the perovskite NCs, favoring their growth int...

Low turn-on fields together with boosted stabilities are recognized as two key factors for pushing forward the implementations of the field emitters in electronic units. In current work, we explored superior flexible field emitters based on single-crystalline 3C-SiC nanowires, which had numbers of sharp edges, as well as corners surrounding the wire body and B dopants. The as-constructed field emitters behaved exceptional field emission (FE) behaviors with ultralow turn-on fields (Eto) of 0.94–0.68 V/μm and current emission fluctuations of ±1.0–3.4%, when subjected to harsh working conditions under different bending cycles, various bending configurations, as well as elevated temperature environments. The sharp edges together with the edges were able to significantly increase the electron emission sites, and the incorporated B dopants could bring a more localized state close to the Fermi level, which rendered the SiC nanowire emitters with low Eto, large field enhancement factor as well as robust current e...

In this work, we reported the growth of cadmium-free Ag-doped Zn–In–S nanocrystals (NCs) with effective photoluminescence (PL) via a hot-injection strategy. The effects of the nucleation temperatures, reaction times, and Ag-doping concentrations on the PL properties of Ag-doped Zn–In–S NCs were investigated systematically. The as-synthesized NCs exhibit color-tunable PL emissions covering a broad visible range of 472–585 nm. After being passivated by a protective ZnS shell, the PL quantum yield (QY) of the resultant NCs was greatly improved up to 33%. With the increase of the Ag-doping level, the PL is significantly intensified due to the improved concentration of Ag ions which provides more holes to recombine with electrons from the bottom of the conduction band. This also makes the emission via the dopant energy level become a powerful, competitive advantage for the NCs with higher Ag-doping levels, resulting in a longer lifetime and higher PL QY. These results suggest that tailoring the Ag-doping level can be a powerful strategy to control the optical properties of Ag-doped Zn–In–S NCs.

A series of Na3YSi3O9:Ce3+ phosphors have been synthesized via a conventional high temperature solid-state reaction. Each crystal structure was characterized by X-ray diffraction (XRD) and refined by the Rietveld method. Luminescence properties of Na3YSi3O9:Ce3+ phosphors such as emission red shifts, fluorescence decay curves, thermal stability, and CIE values were systematically investigated. Upon 300 nm excitation, the emission peaks of Na3YSi3O9:Ce3+ phosphors red shift from 385 nm to 415 nm with Ce3+ concentration increasing from 0.002 to 0.11. Moreover, this red-shift phenomenon also occurs with an excitation wavelength from 270 nm to 340 nm as the Ce3+ concentration determined, which has been explained using the centroid shift and crystal field splitting. The quenching concentration of Ce3+ in the host Na3YSi3O9 is determined to be about 3 mol% and the critical distance is calculated to be about 16.623 A. The energy dispersion mechanism between Ce3+ ions was verified to be a dipole–dipole interaction. Temperature-dependent luminescence of Na3YSi3O9:0.03Ce3+ from 25 °C to 250 °C was evaluated, and the corresponding activation energy ΔE is 0.277 eV. Not only crystal field splitting but also centroid shift plays an important role in the red-shift of the Na3YSi3O9:Ce3+ phosphors, which may contribute to future research in designing novel solid phosphors by modifying composition of the host lattice to affect crystal field splitting and centroid shift, and then adjusting emission wavelengths to match the purposed application.

A novel electrode material, three-dimensional (3D) hierarchical Ni(PO3)2 nanosheet arrays, is explored via a rational topotactic strategy combining hydrothermal growth with subsequent phosphorylation treatment. The as-synthesized Ni(PO3)2 nanosheet arrays self-supported on activated carbon cloth (Ni(PO3)2@ACC) exhibit superior electrochemical capacitive behaviors to a Ni(OH)2 analogue with similar structural characteristics. The areal and mass specific capacitances of the arrays are as high as 4.43 F cm−2 at a current density of 2 mA cm−2 and 2237 F g−1 at ∼1 A g−1, respectively, which is comparable to the best reported results for Ni-based and Me-POx battery-type electrodes. Furthermore, even at a high rate of 10 mA cm−2, the arrays maintain ∼90% charge retention after 2000 cycles, suggesting their robust stability and their very promising applications for energy storage.

Improving the photocatalytic efficiency of TiO2 semiconductor is crucially important and highly desired for its practical applications. In the present work, aiming to broaden the photoresponse window and limit the photocatalyst aggregation, we reported the exploration of N-doped TiO2 thoroughly mesoporous nanofibers with high purity in morphology via a foaming-assisted electrospinning strategy. The foaming agents and urea were introduced in the raw materials to create the mesopores and incorporate the N dopants into the conventional solid TiO2 nanofibers, respectively, which could be accomplished simultaneously over one-step calcination process. The synergetic combination of N dopants and one-dimensional mesoporous nanostructure allow the TiO2 fibers to exhibit significantly enhanced visible-light photocatalytic activity toward the Rhodamine B and hydrogen evolution, as compared to those of N-doped solid and intrinsic thoroughly mesoporous counterparts, suggesting their promising applications in water purification and energy supply.

Dual emission quantum dots (QDs) have attracted considerable interest as a novel phosphor for constructing ratiometric optical thermometry because of its self-referencing capability. In this work, the exploration of codoped Zn–In–S QDs with dual emissions at ≈512 and ≈612 nm from intrinsic Cu and Mn dopants for ratiometric temperature sensing is reported. It is found that the dopant emissions can be tailored by adjusting the Mn-to-Cu concentration ratios, enabling the dual emissions in a tunable manner. The energy difference between the conduction band of the host and Cu dopant states is considered as the key for the occurrence of Mn ion emission. The as-constructed QD ratiometric temperature sensor exhibits a totally robust stability with a fluctuation of ≈ICu/Itot versus times lower than 1% and almost no hysteresis in cycles over a broad window of 100–320 K. This discovery represents that the present cadmium-free, intrinsic dual-emitting codoped QDs can open a new door for the synthesis of novel QDs with stable dual emissions, which poise them well for challenging applications in optical nanothermometry.

Boron nitride nanosheets (BNNSs), as one of the typical two dimensional (2D) few-layered nanomaterials with a structure similar to graphite, have been widely explored and developed due to their unique properties. Recently the temperature sensor based on BN stimulates people’s research interest due to its chemical stability especially at high temperature. In this work, an improved top-down approach was adopted to prepare BN quantum dots (BNQDs) using ultrathin BNNSs as precursors. Strong blue and blue-green photoluminescence (PL) are observed for BNNSs and BNQDs with quantum yields (QYs) of 15.4% and 10%, respectively. Furthermore, for the first time, the temperature-dependent PL of the BNQDs was also researched. Based on this, the activation energy for thermal quenching/population and variation of energy gap with temperature were investigated to understand the PL origin and mechanism. The results show that the broad PL band of BNQDs is related to the strong electron−electron interactions and weak electron−phonon interactions. Meanwhile, the good correspondence between the PL intensity and temperature suggests that BNQDs can be exploited for temperature sensors. The photostability and storage stability as well as excellent reversibility ensure the BNQDs especially suitable for stable and wide-range PL intensity-based temperature sensors.

The intrinsic poor stability of MAPbI3 hybrid perovskites in the ambient environment remains as the major challenge for photovoltaic applications. In this work, complementary first-principles calculations and experimental characterizations reveal that metal cation alloyed perovskite (MABaxPb1–xI3) can be synthesized and exhibit substantially enhanced stability via forming stronger Ba–I bonds. The Ba–Pb alloyed perovskites remain phase-pure in ambient air for more than 15 days. Furthermore, the bandgap of MABaxPb1–xI3 is tailored in a wide window of 1.56–4.08 eV. Finally, MABaxPb1–xI3 is used as a capping layer on MAPbI3 in solar cells, resulting in significantly improved power conversion efficiency (18.9%) and long-term stability (>30 days). Overall, our results provide a simple but reliable strategy toward stable less-Pb perovskites with tailored physical properties.

Molybdenum disulfide (2H-MoS

In the present work, we reported the current emission from P-doped SiC nanowire field emitters, which were synthesized via catalyst-assisted pyrolysis of polysilazane precursors. Directed by F–N theory for enhanced field emission (FE) behaviors, the emitters were grown into nanostructures with two desired characteristics, namely with an ultrahigh aspect ratio as well as incorporated P dopants, which brought profound enhancements to the field enhancement factor (β) and turn-on field (Eto). The as-grown SiC nanowires (SiCNWs) exhibit an aspect ratio over 1500 with a uniform spatial distribution of P dopants. The FE measurements exhibit that the SiCNWs possessed a field enhancement factor up to 11657 and an ultralow Eto of 0.47 V μm−1, which was little achieved among the reported studies. The current emission fluctuations are ∼±4.0% over 5 h, suggesting their good electron emission stability. We mainly attributed the totally excellent FE performances to the ultra-high aspect ratio and the incorporated P dopants of the obtained SiCNWs, which could synergistically cause a significant increase of the field enhancement factor and a decrease of the work function.

A novel and highly efficient visible-light-driven photocatalyst with robust stability, made up of thoroughly mesoporous TiO2/WO3/g-C3N4 ternary hybrid nanofibers, has been fabricated through a foaming-assisted electrospinning process followed by a solution dipping process. These fibers, without the assistance of a noble metal, yielded a high visible-light-driven photocatalytic H2 release rate of ∼286.6 μmol h−1, which was 65 times greater than that displayed by the pure TiO2 counterparts.

Recently, Cu-doped ternary chalcogenide quantum dots (QDs) have attracted extensive attention due to their large Stokes shift and tunable photoluminescence (PL) behavior in the visible and near-infrared (NIR) spectral range, and particularly for their remarkably lower toxicity than their Cd-based counterparts. However, there still remain material- and fabrication-related obstacles in realizing high-performance Cu-doped QDs, which limit their promising applications in light-emitting devices and bio-labeling. In the present study, we report the facile synthesis of high-qualified Cu-doped Zn–In–Se QDs via a hot injection approach, using a heterogeneous dispersion of Se in octadecene (ODE) as a “green” Se precursor. With variation of the ratios of Zn to In, the obtained Cu-doped Zn–In–Se QDs exhibited composition-tunable PL emissions over the most visible spectral window (ca. 565–710 nm) with a PL quantum yield (QY) up to 38% after coating ZnSe shells, which is the highest one ever reported in this system. Furthermore, we report, for the first time, the exploration of QD light-emitting diodes (QD-LEDs) based on the Cu-doped Zn–In–Se QDs as the active layer, which had a maximum luminance of 320 cd m−2 and a luminous efficiency (LE) of 0.97 cd A−1 (at 98 cd m−2), suggesting their promising potential for application in optoelectronic devices.

Aqueous Ag:ZnCdS quantum dots (QDs) with pure, color-tunable fluorescence were prepared based on co-nucleation doping strategy by using a highly reactive S powder precursor, which was reduced by NaBH 4 at high temperature of 180 °C in a closed hydrothermal autoclave. For a meaningful comparison, thiourea as a relatively low reactive precursor was employed to test the advantages of this highly reactive S powder precursor in synthetic chemistry. The influences of various experimental variables, including the Zn/Cd ratio and Ag-doping concentration, on the optical properties of Ag:ZnCdS QDs were systematically investigated. The color-tunable quarternary Ag:ZnCdSeS QDs were also successfully prepared via the variation of Se/S precursor ratio based on the similar reactivity of the Se and S powder precursors. Further, the highly efficient Ag:ZnCdS/ZnS and Ag:ZnCdSeS/ZnS core/shell QDs were constructed by the deposition of the ZnS shell around the crude Ag:ZnCdS and Ag:ZnCdSeS core QDs. The results indicated that this facile synthetic route would provide a versatile approach for preparation of other aqueous multinary metal chalcogenide QDs.

Currently, all-inorganic CsPbX

In the present work, we reported the synthesis of Mn2+-doped Zn–In–S quantum dots (QDs) with high optical performance in a controlled manner. The effects of the temperature, the introduced ODE-S amount and Zn/In ratios in the raw materials, as well as the Mn2+ doping concentrations on the photoluminescence (PL) properties of Mn2+-doped Zn–In–S QDs were investigated systematically. The resultant QDs exhibit tunable bandgaps ranging from 2.9 to 3.7 eV, well-resolved Mn2+ d–d emission with a PL quantum yield (QY) of 56% and a surprisingly long excited state lifetime up to ∼4.2 ms, suggesting their excellent PL properties. Meanwhile, the initial high PL QY of the obtained Mn2+-doped Zn–In–S QDs in organic solvents could be preserved very well once they were transferred into aqueous media via ligand exchange. Furthermore, the as-synthesized QDs exhibit excellent thermal stability up to 200 °C in a crude solution.

High-quality, pure, and color-tunable Ag:ZnCdS quantum dots (d-dots) are prepared by optimization of the experimental conditions including Ag-doping concentration and Zn/Cd precursor ratio. Highly emissive Ag:ZnCdS/ZnS core/shell d-dots with photoluminescence quantum yield (PL QY) as high as 58% are constructed in situ by the growth of a ZnS shell around the crude Ag:ZnCdS solution, which is the highest PL QY reported to date for Ag-based semiconductor d-dots. The emission color of a Ag:ZnCdS d-dot can be tuned toward a larger red region by simple Se treatment at high temperature (220–260 °C). With Se treatment, Ag:ZnCdS alloyed d-dots are transformed into Ag:ZnCdSSe alloyed d-dots, and the corresponding optical changes of d-dots in this process are investigated systematically. This strategy provides a versatile approach for the preparation of other multinary semiconductor nanocrystals.

Colloidal ZnO nanoparticle (NP) films are recognized as efficient electron transport layers (ETLs) for quantum dot light-emitting diodes (QD-LEDs) with good stability and high efficiency. However, because of the inherently high work function of such films, spontaneous charge transfer occurs at the QD/ZnO interface in such a QD-LED, thus leading to reduced performance. Here, to improve the QD-LED performance, we prepared Ga-doped ZnO NPs with low work functions and tailored band structures via a room-temperature (RT) solution process without the use of bulky organic ligands. We found that the charge transfer at the interface between the CdSe/ZnS QDs and the doped ZnO NPs was significantly weakened because of the incorporated Ga dopants. Remarkably, the as-assembled QD-LEDs, with Ga-doped ZnO NPs as the ETLs, exhibited superior luminances of up to 44 000 cd/m2 and efficiencies of up to 15 cd/A, placing them among the most efficient red-light QD-LEDs ever reported. This discovery provides a new strategy for ...