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.
The n-type tungsten oxide (WO 3 ) polycrystalline thin films have been prepared at an optimized parameters (0.20M, 5 ml and 500 o C) using jet nebulizer spray pyrolysis (JNSP) technique. Such prepared WO 3 films were characterized by XRD, SEM, EDAX, UV-vis from I-V. The XRD pattern of the optimized WO 3 film reveals the monoclinic structure. The SEM and EDAX images shows that the surface morphological variations and elements present were confirmed. The optical properties were recorded by UV-vis spectrum and the maximum band gap value was observed as 3.86 eV for 500°C. The maximum conductivity of the prepared WO 3 was recorded as 1.201 x 10 -8 S/cm from I-V characterization for 500°C.Using J-V plot, the diode parameters of n-WO 3 /p-Si prepared at 500°C with 0.2 M and 5 ml were measured under dark and illumination. The ideality factor (n) and barrier height (Φ b ) values of n-WO 3 /p-Si diode are obtained as 5.8 and 0.80 eV in dark and 3.9 and 0.81 eV under illumination.
Films of CdSe(ZnS) colloidal nanocrystalline quantum dots (NQDs) were deposited on bare silicon, glass and polymer coated silicon using mist deposition. This effort is a part of an exploratory investigation in which this deposition technique is studied for the first time as a method to form semiconductor NQD films. The process parameters, including deposition time, solution concentration and electric field, were varied to change the thickness of the deposited film. Blanket films and films deposited through a shadow mask were created to investigate the method's ability to pattern films during the deposition process. The differences between these deposition modes in terms of film morphology were observed. Overall, the results show that mist deposition of quantum dots is a viable method for creating thin, patterned quantum dot films using colloidal solution as the precursor. It is concluded that this technique shows very good promise for quantum dot (light emitting diode, LED) fabrication.
In this work, the process of mist deposition is explored as a method used to deposit organic semiconductors for applications in organic light emitting diodes (OLEDs). The deposition kinetics of a specially formulated hole transport agent is studied. The results indicate that the mist-deposited organic film thickness varies linearly with precursor concentration, deposition time and substrate potential. Depending upon process parameters, a deposition rate in the range of 50 nm min −1 is readily achievable. Evolution of surface roughness revealed distinct stages in the film formation process. The growth of secondary layers was observed before the formation of a complete initial film layer. A working OLED with the hole transport layer deposited by mist deposition was demonstrated. The luminance of the device was measured to be a maximum of 3000 cd m −2 and the efficiency was 6.7 cd A −1 .
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.