A dual‐phase all‐inorganic composite CsPbBr3‐CsPb2Br5 is developed and applied as the emitting layer in LEDs, which exhibited a maximum luminance of 3853 cd m–2, with current density (CE) of ≈8.98 cd A–1 and external quantum efficiency (EQE) of ≈2.21%, respectively. The parasite of secondary phase CsPb2Br5 nanoparticles on the cubic CsPbBr3 nanocrystals could enhance the current efficiency by reducing diffusion length of excitons on one side, and decrease the trap density in the band gap on the other side. In addition, the introduction of CsPb2Br5 nanoparticles could increase the ionic conductivity by reducing the barrier against the electronic and ionic transport, and improve emission lifetime by decreasing nonradiative energy transfer to the trap states via controlling the trap density. The dual‐phase all‐inorganic CsPbBr3‐CsPb2Br5 composite nanocrystals present a new route of perovskite material for advanced light emission applications.
C-axis vertically aligned ZnO nanorod arrays were synthesized on a ZnO thin
film through a simple hydrothermal route. The nanorods have a diameter
of 30–100 nm and a length of about several hundred nanometres. The gas
sensor fabricated from ZnO nanorod arrays showed a high sensitivity to
H2
from room temperature to a maximum sensitivity at
250 °C
and a detection limit of 20 ppm. In addition, the ZnO gas sensor also exhibited excellent responses
to NH3
and CO exposure. Our results demonstrate that the hydrothermally grown vertically
aligned ZnO nanorod arrays are very promising for the fabrication of cost effective and high
performance gas sensors.
Single crystal zinc oxide nanocombs were synthesized in bulk quantity by vapor phase transport. A glucose biosensor was constructed using these nanocombs as supporting materials for glucose oxidase ͑GO x ͒ loading. The zinc oxide nanocomb glucose biosensor showed a high sensitivity ͑15.33 A/cm 2 mM͒ for glucose detection and high affinity of GO x to glucose ͑the apparent Michaelis-Menten constant K M app = 2.19 mM͒. The detection limit measured was 0.02 mM. These results demonstrate that zinc oxide nanostructures have potential applications in biosensors.
In this letter, the authors report a dye-sensitized solar cell (DSSC) using a ZnO-nanoflower film photoanode, which was grown by a hydrothermal method at 95°C. The dye used was cis-bis(isothiocyanato)bis(2,2′-bipyridyl-4,4′-dicarboxylato)-ruthenium(II) bis-tetrabutylam-monium (N-719). At AM1.5G irradiation with 100mW∕cm2 light intensity, the DSSC based on ZnO-nanoflower film showed an energy conversion efficiency of 1.9%, which is much higher compared to that (1.0%) of the control device constructed using a photoanode of upstanding ZnO-nanorod array fabricated by hydrothermal method as well. The better performance of ZnO-nanoflower DSSC was due to a better dye loading and light harvesting of the ZnO-nanoflower film. The results demonstrate potential application of ZnO-nanoflower array for efficient dye-sensitized solar cells.
We reported an efficient inverted bulk-heterojunction ͓regioregular of poly͑3-hexylthiophene͒: ͑6,6͒-phenyl C 61 butyric acid methyl ester͔ solar cell with a highly transparent sol-gel derived ZnO film as electron selective layer and MoO 3 as hole selective layer. By modifying the precursor concentration of sol from 0.75 to 0.1M, the optical transmittance of ZnO film increases from 75% to 95%. This improvement in transmittance increases the short-circuit density of inverted solar cell from 5.986 to 8.858 mA/ cm 2 without sacrificing the open-circuit voltage and fill factor of the device. We also demonstrated that the device incorporated with MoO 3 has a larger open-circuit voltage and fill factor than the device without MoO 3. Power conversion efficiency of 3.09% was achieved under simulated AM 1.5G illumination of 100 mW/ cm 2 .
Organometal halide perovskite has recently emerged as a very promising family of materials with augmented performance in electronic and optoelectronic applications including photovoltaic devices, photodetectors, and light-emitting diodes. Herein, we propose and demonstrate facile solution synthesis of a series of colloidal organometal halide perovskite CH3NH3PbX3 (X = halides) nanoparticles with amorphous structure, which exhibit high quantum yield and tunable emission from ultraviolet to near-infrared. The growth mechanism and photoluminescence properties of the perovskite amorphous nanoparticles were studied in detail. A high-efficiency green-light-emitting diode based on amorphous CH3NH3PbBr3 nanoparticles was demonstrated. The perovskite amorphous nanoparticle-based light-emitting diode shows a maximum luminous efficiency of 11.49 cd/A, a power efficiency of 7.84 lm/W, and an external quantum efficiency of 3.8%, which is 3.5 times higher than that of the best colloidal perovskite quantum-dot-based light-emitting diodes previously reported. Our findings indicate the great potential of colloidal perovskite amorphous nanoparticles in light-emitting devices.
High‐quality InP/ZnS core–shell nanocrystals with luminescence tunable over the entire visible spectrum have been achieved by a facile one‐pot solvothermal method. These nanocrystals exhibit high quantum yields (above 60%), wide emission spectrum tunability and excellent photostability. The FWHM can be as narrow as 38 nm, which is close to that of CdSe nanocrystals. Also, making use of these nanocrystals, we further demonstrated a cadmium‐free white QD‐LED with a high color rendering index of 91. The high‐performance of the resulting InP/ZnS NCs coupled with their low intrinsic toxicity may further promote industrial applications of these NC emitters.
We report herein a glucose biosensor based on glucose oxidase (GOx) immobilized on ZnO nanorod array grown by hydrothermal decomposition. In a phosphate buffer solution with a pH value of 7.4, negatively charged GOx was immobilized on positively charged ZnO nanorods through electrostatic interaction. At an applied potential of +0.8V versus Ag∕AgCl reference electrode, ZnO nanorods based biosensor presented a high and reproducible sensitivity of 23.1μAcm−2mM−1 with a response time of less than 5s. The biosensor shows a linear range from 0.01to3.45mM and an experiment limit of detection of 0.01mM. An apparent Michaelis-Menten constant of 2.9mM shows a high affinity between glucose and GOx immobilized on ZnO nanorods.
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