Dissertation > Mathematical sciences and chemical > Physics > Semiconductor physics > Semiconductive Theory > Semiconductor quantum theory

Optical Properties of Zn-based Quantum Dots and Application in LED

Author HuangQingSong
Tutor LiZuo;ZhangXiaoSong;XuJianPing
School Tianjin University of Technology
Course Condensed Matter Physics
Keywords Quantum dots Fluorescence decay Photoluminescence Electroluminescent
CLC O471.1
Type Master's thesis
Year 2010
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Semiconductor quantum dots because of their unique physical and chemical properties as well as biomedical and optoelectronic devices great application prospects, has developed into one of the most active in areas such as physics, chemistry, material research. The synthesis of high-quality quantum dots, and in-depth study of the nature of their optical, electrical, and other very important significance, an important prerequisite for their applications in optoelectronic devices. The thesis ZnS and Mn ions doped ZnS quantum dots as the main object of study, a systematic study of the precursors, coated and temperature on ZnS quantum dots and doping ion optical performance; while in turn zinc oxide and sulfide as a light-emitting layer, the finishing layer is applied to the electroluminescent device, and its photoelectric properties. The specific contents are as follows: 1, the basis of this preliminary work, the use of aqueous phase co-precipitation method synthesized precursor [S 2 - ] / [Zn 2 than ZnS and Mn ions doped ZnS quantum dots using XRD, HRTEM, UV absorption spectroscopy, and fluorescence spectroscopy, fluorescence decay spectroscopy to the characterization and analysis. Characterization results show that by controlling the precursor [S 2 - ] / [Zn 2 ] ratio, effectively control sample was prepared in particle diameter, color coordinate and color temperature; The study found that the With [S 2 - ] / [Zn 2 ] than the increase in the index of ZnS the matrix Mn ions life are attenuation and renders the regular change, analysts believe that the ZnS matrix and Mn ions around the defect with [S 2 - ] / [Zn 2 ] caused changes. To study the effects of test temperature on the Mn ions doped ZnS quantum dot fluorescence and fluorescence decay. The results found that as the temperature increases, Mn ions associated emission intensity showing the temperature quenching effect, and its fluorescence decay becomes faster. 2, TGA coated Mn ions doped ZnS quantum dot fluorescence and fluorescence decay. The study found that the emission intensity of the Mn ions is reduced with the increase in the proportion of TGA coated This is mainly due to a TGA in the S group with Zn ions (or S-ion) is formed between the S-Zn key (or S-Mn bond ) lead to a quantum dot excited state electron transfer to the TGA cause. At the same time, we take advantage of Fluorescence Spectroscopy confirms this conclusion. Preliminary exploration of different solvents on ZnS: Mn quantum dots dispersed, film-forming impact basis ZnS: Mn quantum dots as light-emitting layer modified layer prepared single-layer and multilayer electrical electroluminescent devices, and to explore the photoelectric performance. The results showed that, when of ZnS: Mn as a luminescent layer, MN + emission at 597 nm at, compared with the PL spectra redshift 5nm; as the finishing layer, as compared with the single-layer organic devices IV curve and emission spectra has been reduced. The analysis results show that the adding of the quantum dot layer, not only modification of the surface of the ITO uneven, balanced by the mobility of the carrier energy is passed, but also as a light emitting layer, thereby to some extent improve the organic electroluminescent device electrical The approximately spherical ZnS quantum dots with 380nmInGaN chip bonding performance and the luminous intensity with LSS synthesized, a white light emitting diode was prepared, color coordinates of (0.29, 0.30), can be used for white illumination fields.

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