Electroluminescence Of Quantum Dots Doping With Organic Polymer

Quantum dots is a kind of ideal fluorescent material because of its wide range of excitation spectrum and continuous, narrow and symmetric photoluminescence spectra, emitting light colors can be adjusted, good photochemical stability, high electron mobility. Quantum dots have great application potential in electroluminescent devices. The study of quantum dots and organic polymer composite electroluminescent has important theoretical significance and application value.In this paper, red-emitting dots and MEH-PPV composite electroluminescent devices, blue-emitting quantum dots and PVK composite electroluminescent devices, and red-emitting quantum dots and PVK composite electroluminescent devices, were researched. We observed some phenomenena:the red-emitting quantum dots emit red light at higher voltage after MEH-PPV’s electroluminescence at lower voltage in red-emitting quantum dots and MEH-PPV composite electroluminescent devices; blue-emitting quantum dots and PVK composite electroluminescent devices emitting saturate blue light at a relatively low doping concentration of quantum dots; A slight red-shift of emitting peak occurs in the electroluminescenct spectra among the devices with different doping concentration. We provide some reansonable explanation for these phenomena:Firstly, the red-emitting quantum dots play a role of electron trap in red-emitting quantum dots and MEH-PPV compsite electroluminescenct devices; Secondly, blue-emitting quantum dots have a good phase separation with PVK after spin-casting process, the thickness of quantum dots layer has a obvious influence on the electroluminescenect spectra of blue-emitting quantum dots and PVK composite electroluminescent devices; Thirdly, red-shift occurs because of the closer distance between quantum dots give rise to FRET (fluorescence resonance energy transfer).Studing the electronic process and spectra which change with the driving voltage and quantum dots’ doping concentration, could provide important guidance and reference to achieve quantum dots and organic polymer composite electroluminescent devices with good processability and stable physical and chemical properties.