The Controllabe Synthesis Of CdTe Quantum Dots And Their Luminescent Properties

We are mainly focus on the controllable synthesis of CdTe quantum dots and its luminescent properties.Firstly,we synthesize the quantum dot with different sizes by controlling synthesis temperature and growth time.We carried out doped process(europium)of CdTe quantum dot in order to improving their luminescence property.Finally,Inkjet printing method was employed to fabricate light emitting diodes(LEDs)using as-synthesized quantum dots as the active layer.The brief content of the thesis as follows:The CdTe QDs were synthesized by solvothermal technique and the effect of synthesis temperature and growth time on the luminescence properties of as-synthesized QDs were studied systematically.Interestingly,the synthesis temperature and reaction time would great influence on the luminescence properties of QDs.In brief,we found that the elevated temperature would increase the rate of quantum dot' growth.When the temperature is below 170? the synthesized QDs would emit the green luminescence and while the temperature is higher than 200?,orange and yellow emission quantum dot would be dominant.However,extension of the reaction time,the emission peak and absorption peak shows the red shift,but the movement of absorption peak is slower than the emission peak which result in the larger stoke shift.The europium doped CdTe QDs(E-CdTe)were synthesized by optimizing the temperature and reaction time.It is observed that europium would obviously promote the growth rate and improve the homogeneous growth of quantum dot which make us to synthesis 650nm emission quantum dot more quickly and simple.The effect of europium concentration on the luminescence properties of CdTe QDs was studied.It can be conclude that the higher ratio of europium,would enhance the red emission.Finally,the as synthesized QDs were dissolved in octane to prepare the ink for injet printer.The structure of device is Al/ZnO/QDs/PVK/TPD/PEDOTPSS/ITO.All the layers were spin coated except the QD later.The quantum dot light emission diode prepared by quantum dot film was running at the voltage of 3 V.When the voltage increase to 9V,the device's luminance reach to the maximum luminescence,the luminance was 1940cd/m2,and the current efficiency was 3.74cd/A.This has great significance of inkjet printing method apply on device prepared in the future.In this thesis,we synthesized yellow and green emission quantum dot by controlling the heating time,the heating temperature.And we synthesized crimson emission quantum dot by doping europium,then we successful prepared quantum dot light emission diode by using ink-jet printing method.Thus,this thesis has some innovative and practically to certain extend.