Published online by Cambridge University Press: 15 February 2016
All inorganic quantum dot light emitting devices with solution processedtransport layers are investigated. The device consists of an anode, a holetransport layer, a quantum dot emissive layer, an electron transport layer and acathode. Indium tin oxide coated glass slides are used as substrates with theindium tin oxide acting as the transparent anode electrode. The transport layersare both inorganic, which are relatively insensitive to moisture and otherenvironmental factors as compared to their organic counterparts. Nickel oxideacts as the hole transport layer, while zinc oxide nanocrystals act as theelectron transport layer. The nickel oxide hole transport layer is formed byannealing a spin coated layer of nickel hydroxide sol-gel. On top of the holetransport layer, CdSe/ZnS quantum dots synthesized by hot injection method isspin coated. Finally, zinc oxide nanocrystals, dispersed in methanol, are spincoated over the quantum dot emissive layer as the electron transport layer. Thematerial characterization of different layers is performed by using absorbance,Raman scattering, XRD, and photoluminescence measurements. The completed deviceperformance is evaluated by measuring the IV characteristics,electroluminescence and quantum efficiency measurements. The device turn on isaround 4V with a maximum current density of ∼200 mA/cm2 at9 V.