The Structure Design Of CdSe@ZnS Quantum Dots-light Emitting Diode And Test Of Photoelectric Performance

With the characteristics of narrow emission spectrum,high luminous efficiency,adjustable spectrum,long fluorescence lifetime and good solution stability,quantum dots are considered as a very promising luminescent material in application of virtual reality?VR?,car desktop monitors,smart phone,tablet personal computers and other display devices.QLED,that is,quantum dots light emitting diodes,which is the application of quantum dots in the field of light-emitting diodes?LEDs?.QLED has the advantages of high brightness,good stability,high color saturation,wide color gamut and so on.It has a strong competitive advantage in the new generation of display technology.The first generation of organic light-emitting diode is a small molecule organic devices,with sandwich structure to form organic double layer structure.But the high efficiency of OLED needs a multilayer structure to balance the carrier transport,ease of exciton composite luminescence.In the late 1990's,structure of organic light emitting diodes become more complex,the carrier injection,multilayer structure of the device including carrier transport layer,exciton composite layer and luminous layer.Multilayer devices can be deposited by vacuum thermal deposition,which has low material utilization,poor scalability,high cost and difficulty in patterning.Solution spin-coating method can reduce the manufacturing cost.With continuous exploration and research,QLED devices assembled by solution spin-coating method have drawn many attentions.The assembly process of solution process greatly simplifies the fabrication process and facilitates making large-area light-emitting devices.According to the different carrier transport layers,the quantum dot light emitting diodes can be divided into inorganic carrier transport layer QLED and organic carrier transport layer QLED,although the inorganic carrier transport layer has certain air stability,But the holes and electrons are not balanced,the electron injection rate is too large,and the hole injection rate is small,this imbalanced carrier transfer rate resulting in quantum dot charge and fluorescence quenching.Therefore,it is important to select the appropriate carrier transport layer.Aiming at the problems of QLED,the following research work is carried out in this paper:?1?CH₃NH₃PbBr₃ quantum dots were prepared by solution method,and DMF was used as a good solvent.CH₃NH₃ PbBr and PbBr₂ were used as precursors,and the mixed solution was injected into the poor solvent toluene quickly.By controlling the temperature of poor solvent toluene to control CH₃NH₃ PbBr₃ nanocrystal size of perovskite quantum dots,and through transforming different surfactants and adjusting the reaction time to control the morphology of perovskite nanocrystals.The quantum yield of the synthesized CH₃NH₃ PbBr₃ quantum dot is 89.6%.The size distribution of quantum dots is uniform and has high fluorescence intensity.?2?Cd Se@Zn S quantum dots with core-shell structure were successfully prepared by microfluidic method.Cd O?TOP and Se were used as precursors,ODE was used as the solvent,respectively.Changing the luminescence spectra in the visible range.Cd Se@Zn S quantum dots solution with high fluorescence lifetime,high quantum yield and environmental stability were abtained.?3?Cd Se@Zn S colloidal quantum dots synthesized by microfluidic method were used as light-emitting layer materials.The ITO/PEDOT:PSS/Poly-TPD/Cd Se@Zn S/PCBM/Li F:Al quantum dot light-emitting diodes were successfully assembled by spin-coating,and I-E performance testing of whole device were acted.The results show that the device has good luminescent properties.?4?Cd Se@Zn S colloidal quantum dots synthesized by the microsomal method were used as the luminescent layer material,the p-type Ni O thin films prepared by hydrothermal method were used as the hole transporting layer.And the ITO/PEDOT:PSS/Ni O/Cd Se@Zn S/PCBM/Li F:Al device were assembly succeeded.The results show that the device has the characteristics of diode,and I-E performance testing of whole device were acted,the testing results clearly show the characteristics of the diode.