高性能藍(lán)光量子點(diǎn)發(fā)光二極管電子注入特性的研究
發(fā)布時(shí)間：2018-08-31 13:59
【摘要】：因其諸多優(yōu)越的性質(zhì),膠體量子點(diǎn)(QDs)技術(shù)在過去30年里迅猛發(fā)展,逐漸應(yīng)用于生產(chǎn)、科研中的各個(gè)領(lǐng)域。而II-VI族半導(dǎo)體量子點(diǎn)材料具有優(yōu)越的量子產(chǎn)率、色純度與光色可調(diào)性,是制備LED器件的理想材料。從1994年加州大學(xué)的Alivisatos等首次研制出膠體量子點(diǎn)LED(QLED)以來,量子點(diǎn)電致發(fā)光器件在材料、器件結(jié)構(gòu)、制備工藝等方面都有了長(zhǎng)足的進(jìn)步。這些技術(shù)進(jìn)步還伴隨著人們對(duì)量子點(diǎn)電致發(fā)光效應(yīng)背后的相關(guān)物理過程愈加深入的理解。然而,由于QD層的大帶隙引起的電荷注入困難,藍(lán)色QLED的性能目前顯然劣于綠色和紅色的性能。本文中,我們引入了一種部分自然氧化鋁陰極(Al:Al2O3),利用ZnCdS/ZnS核殼結(jié)構(gòu)量子點(diǎn)作為發(fā)光材料,制備了性能優(yōu)良的藍(lán)光量子點(diǎn)LED器件。器件的亮度達(dá)13000 cd/m2,最高電流效率1.1 cd/A,并且有著457 nm的電致發(fā)光峰與20.8 nm的半峰寬,展現(xiàn)出純凈的深藍(lán)發(fā)射光。我們還對(duì)自然氧化制備的Al:Al2O3進(jìn)行了一系列表征分析,證實(shí)了其對(duì)電子注入與激子有效復(fù)合的促進(jìn)作用。這種自然氧化方法工藝簡(jiǎn)單價(jià)格低廉,為QLED中電子注入層/陰極的制備提供了新的思路。在Al:Al2O3陰極的基礎(chǔ)上,本文還將Zn O納米顆粒作為電子傳輸層插入量子點(diǎn)層與陰極之間制備LED器件,并調(diào)節(jié)ZnO層制備的條件,進(jìn)一步提高了器件的性能。通過調(diào)控ZnO層退火的條件控制載流子注入的平衡,我們最終制備出了亮度高達(dá)37000 cd/m2,電流效率4.5 cd/A的高性能藍(lán)光量子點(diǎn)LED器件。據(jù)我們所知,該器件的亮度是目前為止藍(lán)光QLED的紀(jì)錄。比較不同退火條件的ZnO層結(jié)合不同的陰極制備器件的性能,我們確定了ZnO的制備條件對(duì)于其中缺陷態(tài)密度以及電子遷移率的調(diào)整。這種調(diào)控載流子注入的平衡的方法不必改變器件原有結(jié)構(gòu),可以通過簡(jiǎn)單的退火手段使不同器件結(jié)構(gòu)的載流子注入平衡達(dá)到最優(yōu),對(duì)量子點(diǎn)LED器件的相關(guān)后續(xù)研究具有啟發(fā)意義。
[Abstract]:Because of its many superior properties, colloidal quantum dot (QDs) technology has developed rapidly in the past 30 years, and has been gradually applied in various fields of production and scientific research. However, II-VI semiconductor quantum dot materials have excellent quantum yield, color purity and photochromatic tunability, so they are ideal materials for the preparation of LED devices. Since the first development of colloidal quantum dot (LED (QLED) by Alivisatos of the University of California in 1994, quantum dot electroluminescent devices have made great progress in material, device structure and fabrication process. These advances have been accompanied by a deeper understanding of the physical processes behind the quantum dot electroluminescence. However, due to the difficulty of charge injection due to the large band gap in QD layer, the performance of blue QLED is obviously inferior to that of green and red at present. In this paper, we introduce a partial natural alumina cathode (Al:Al2O3) and use ZnCdS/ZnS core-shell structure quantum dots as luminescent materials to fabricate blue quantum dot LED devices with excellent performance. The luminance of the device is up to 13000 cd/m2, the maximum current efficiency is 1.1 cd/A, and the luminescence peak of 457 nm is half width of 20.8 nm, showing pure dark blue emission. A series of characterization and analysis of Al:Al2O3 prepared by natural oxidation have also been carried out, and it has been proved that it can promote the effective recombination of electron injection and exciton. This natural oxidation process is simple and cheap, which provides a new idea for the preparation of electron injection layer / cathode in QLED. On the basis of Al:Al2O3 cathode, the Zn O nanoparticles were inserted into the quantum dot layer and cathode as the electron transport layer to fabricate the LED device, and the preparation conditions of the ZnO layer were adjusted to further improve the performance of the device. By adjusting the condition of annealing in ZnO layer to control the equilibrium of carrier injection, we have finally fabricated a high performance blue quantum dot LED device with a luminance up to 37000 cd/m2, current efficiency of 4.5 cd/A. As far as we know, the brightness of the device is so far the record of Blu-ray QLED. Comparing the properties of ZnO layers with different cathodic fabrication devices under different annealing conditions, we determine the adjustment of the defect density of states and electron mobility for the preparation conditions of ZnO. This method of adjusting the equilibrium of carrier injection does not need to change the original structure of the device, and the carrier injection equilibrium of different device structures can be optimized by simple annealing method. It has enlightening significance for further research on quantum dot LED devices.
【學(xué)位授予單位】：華北電力大學(xué)(北京)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2017
【分類號(hào)】：TN312.8
本文編號(hào)：2215205
[Abstract]:Because of its many superior properties, colloidal quantum dot (QDs) technology has developed rapidly in the past 30 years, and has been gradually applied in various fields of production and scientific research. However, II-VI semiconductor quantum dot materials have excellent quantum yield, color purity and photochromatic tunability, so they are ideal materials for the preparation of LED devices. Since the first development of colloidal quantum dot (LED (QLED) by Alivisatos of the University of California in 1994, quantum dot electroluminescent devices have made great progress in material, device structure and fabrication process. These advances have been accompanied by a deeper understanding of the physical processes behind the quantum dot electroluminescence. However, due to the difficulty of charge injection due to the large band gap in QD layer, the performance of blue QLED is obviously inferior to that of green and red at present. In this paper, we introduce a partial natural alumina cathode (Al:Al2O3) and use ZnCdS/ZnS core-shell structure quantum dots as luminescent materials to fabricate blue quantum dot LED devices with excellent performance. The luminance of the device is up to 13000 cd/m2, the maximum current efficiency is 1.1 cd/A, and the luminescence peak of 457 nm is half width of 20.8 nm, showing pure dark blue emission. A series of characterization and analysis of Al:Al2O3 prepared by natural oxidation have also been carried out, and it has been proved that it can promote the effective recombination of electron injection and exciton. This natural oxidation process is simple and cheap, which provides a new idea for the preparation of electron injection layer / cathode in QLED. On the basis of Al:Al2O3 cathode, the Zn O nanoparticles were inserted into the quantum dot layer and cathode as the electron transport layer to fabricate the LED device, and the preparation conditions of the ZnO layer were adjusted to further improve the performance of the device. By adjusting the condition of annealing in ZnO layer to control the equilibrium of carrier injection, we have finally fabricated a high performance blue quantum dot LED device with a luminance up to 37000 cd/m2, current efficiency of 4.5 cd/A. As far as we know, the brightness of the device is so far the record of Blu-ray QLED. Comparing the properties of ZnO layers with different cathodic fabrication devices under different annealing conditions, we determine the adjustment of the defect density of states and electron mobility for the preparation conditions of ZnO. This method of adjusting the equilibrium of carrier injection does not need to change the original structure of the device, and the carrier injection equilibrium of different device structures can be optimized by simple annealing method. It has enlightening significance for further research on quantum dot LED devices.
【學(xué)位授予單位】：華北電力大學(xué)(北京)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2017
【分類號(hào)】：TN312.8
【參考文獻(xiàn)】
相關(guān)期刊論文 前1條
1 柳楊;劉志偉;卞祖強(qiáng);黃春輝;;高效、穩(wěn)定Ⅱ-Ⅵ族量子點(diǎn)發(fā)光二極管(LED)的研究進(jìn)展[J];無機(jī)化學(xué)學(xué)報(bào);2015年09期
，本文編號(hào)：2215205
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