Alcohol-Soluble CdSe Quantum Dots Based On Light Emitting Diodes

As one of the most widely used quantum dots,CdSe quantum dots exhibit high photoluminescent quantum yield,narrow line width,high stability and mature synthesis technology.Although the electroluminescent devices based on CdSe quantum dots have approached the commercial level in the lab,the unbalanced charge injection and low device efficiency inhibit its commercialization.In order to solve these problems,we use the alcoholsoluble CdSe quantum dots rather than oil-soluble CdSe quantum dots as emissive layer in electroluminescent devices.From the aspect of surface ligands of quantum dots,we performed ex-situ ligand exchange strategy,6-mercaptohexanol with short chains is used to replace traditional oleylamine ligand with long chains.Then,inverted electroluminescent devices were fabricated through all solution processed method.The main progress we obtained are summarized as follows:(1)Alcohol-soluble CdSe quantum dots are dispersed in polar solvents such as isopropanol.Since isopropanol and chlorobenzene are the orthogonal solvent,the quantum dot film is less damaged during the deposition of TFB,and then improve the machinability of inverted devices;(2)We made performance Comparison of Electroluminescent Devices based on alcoholsoluble CdSe quantum dots and oil-soluble CdSe quantum dots.Electroluminescent devices based on alcohol-soluble CdSe quantum dots have lower turn on voltage,higher maximum luminance and higher efficiency than those based on oil-soluble CdSe quantum dots.The HOMO level of the quantum dots increases by 0.1 eV,indicating reduced potential barrier between TFB and the quantum dots,and accelerated rate of hole injection.(3)Transparent devices were constructed with alcohol-soluble CdSe quantum dots.