We report a multilayer solution-processed blue light-emitting diode based on colloidal core/shell CdS/ZnS nanocrystal quantum dots (QDs). At a low-operating voltage of 5.5 V, the device emits spectrally pure blue radiation at 460 nm with a narrow full-width-at-half-maximum bandwidth of 20 nm and high brightness up to 1600 cd/m2. Broad-band, long-wavelength emission from the polymer components and deep traps in the QDs are minimized to less than 5% of the total emission.

In this letter, we report a mist-deposition process for the assembly and patterning of nanocrystal quantum dots (NQDs) during the fabrication of quantum dot light emitting diodes (QD-LEDs), which allows for tight controls over the thickness, surface morphology, composition, and resolution of NQD emissive layers. A defect-free featuring uniform brightness QD-LED containing a mist-deposited emissive CdSe(ZnS) NQD layer was demonstrated. Additionally, the technique of successive mist deposition of multicolor NQDs through a set of registered shallow masks was employed to create a 6×6 matrix of alternating pixels composed of 5nm diameter CdSe(ZnS) NQDs (green) and 8nm diameter CdSe(ZnS) NQDs (red) on the same substrate. The results obtained demonstrate the potential of mist-deposition technology in the future development of full-color QD-LED displays.

A Si-based quantum-dot light-emitting diodeWe report the demonstration of mechanically flexible quantum dot light emitting diodes ͑QD-LEDs͒ of all three primary colors ͑red, green, and blue͒. The QD-LEDs have been fabricated over poly͑ethylene-terephthalate͒ substrates and exhibited high brightness, saturated colors, and pronounced flexibility with a critical bending radius of ϳ5 mm. The efficiencies of the flexible QD-LEDs are comparable with the devices fabricated on rigid substrates, suggesting the intrinsic flexibility of quantum dot-based optoelectronic devices.

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Reduced pressure etching of thermal oxide in anhydrous HF gas with three different alcoholic solvent vapors is studied. Thermal oxide etch rates as functions of temperature, pressure, time, and HF partial pressure are presented for methanol, ethanol‐water azeotrope (95.6% ethanol, 4.4% water), and 2‐propanol (isopropyl alcohol). The etch rates are interpreted in terms of alcohol vapor pressure, HF ionization, and reaction product desorption. The efficient desorption of reaction products compared to vapor HF/H2O is believed to be responsible for both the wider process window for alcoholic solvents and the alleviation of the solid residue formation problem. Among the alcoholic solvents studied, methanol has the best potential while 2‐propanol can also be useful in selected applications.