胶体硒化铅量子点发光二极管的研制及其应用

发布时间：2018-04-25 12:44

本文选题：PbSe量子点 + 荧光粉　；参考：《吉林大学》2016年博士论文

【摘要】：半导体量子点自身具有多种特性,比如量子限域效应、小尺寸效应、表面效应、介电受限效应等。同时,量子点具有吸收光谱覆盖范围广、发光效率高、发光峰窄、稳定性高等优点。所以,它在生物学、光电器件、发光器件、检测等领域都有着非常广阔的应用前景。针对传统近红外光源制作成本高、加工工艺复杂、波长不易调节等不足,本文首次利用近红外Pb Se胶体量子点作为光转换材料,以Ga N发光二极管作为激发光源制作了一种新型的近红外光源。之后利用此光源对几种易燃易爆气体进行了检测并取得了一些创新性应用,具体如下:1.基于Pb Se量子点近红外发光二极管的研制。现有的近红外量子点电致发光二极管由于存在大量非辐射复合,导致其发光效率一直不高,且远落后于可见光的量子点发光器件。所以本文将Pb Se量子点分散在紫外胶水中作为光转换材料,以Ga N发光二极管作为激发光源制作出一种新型结构的单波长近红外光源。通过对光源的性能表征发现:器件的最佳外量子效率可达2.52%;器件的稳定性较好;简单的通过改变量子点尺寸的方式就可以改变器件的发光波长。2.以单波长Pb Se量子点发光二极管作为光源检测乙炔气体。某些气体与量子点表面间的化学反应会使量子点的荧光光谱发生变化,例如荧光淬灭,荧光强度下降等,所以现在使用量子点检测气体的工作大多数都是利用了量子点的这一特点。然而,这种检测方法的灵敏度不高,同时,想要将此技术进行实际应用还有很多问题。为此我们开发了一种新型的使用量子点检测气体的方法,那就是利用Pb Se量子点近红外光源为检测光源,采用直接吸收光谱法对乙炔气体进行检测。该检测系统的检测下限为20ppm,检测精度为2%。3.利用多波长Pb Se量子点发光二极管作为检测光源对多种气体进行同时检测。将4.6、5.1、6.1nm三种尺寸的Pb Se量子点集成在一个Ga N发光二极管芯片上成功制作出一种可以发射1526、1676、1948nm三个波长的近红外光源。利用这个光源作为检测光源,采用直接吸收光谱法对甲烷、乙炔、氨气进行了同时检测。得到的检测下限分别为100,20,20ppm,检测精度为2%,达到了同时检测多气体的目的。4.利用可分别调制的多波长Pb Se量子点发光二极管作为检测光源,采用差分吸收法对两种气体进行同时检测。我们选择了一种带有三个独立芯片的Ga N发光二极管作为激发光源,这三个芯片拥有独立的电极,可以分别进行调制。将2.53、4.83、6.88nm三种尺寸的Pb Se量子点分别集成在三个芯片上就制作出一种三个波长可以分别调制的近红外光源。我们利用此光源采用差分吸收法对乙炔和氨气进行了同时检测。差分光谱法可以消除由于光源不稳定而带来的误差。为了简化检测系统,我们用光探测器替代了光谱仪,光程长度也相应缩短一半。最终,乙炔和氨气的检测下限分别为25和30ppm,检测误差小于2%。
[Abstract]:Semiconductor quantum dots have many properties, such as quantum limiting effect, small size effect, surface effect, dielectric confinement effect and so on. At the same time, quantum dots have the advantages of wide absorption spectrum coverage, high luminescence efficiency, narrow luminescence peak and high stability. Therefore, it has a very broad application prospect in biology, optoelectronic devices, luminescent devices, detection and other fields. Aiming at the disadvantages of the traditional near infrared light source, such as high cost, complex processing technology and difficult to adjust the wavelength, the near infrared Pb se colloidal quantum dots are used as optical conversion materials for the first time in this paper. A novel near infrared light source was fabricated with gan LED as excitation source. Then the light source is used to detect several flammable and explosive gases and some innovative applications are obtained, as follows: 1. Development of near Infrared Light emitting Diode based on Pb se Quantum Dots. Due to the existence of a large number of non-radiative recombination, the existing near-infrared quantum dot electroluminescent diodes have low luminescence efficiency and lags far behind the visible light emitting devices. In this paper, Pb se quantum dots are dispersed in UV glue as optical conversion materials, and gan LED is used as excitation source to produce a new type of single wavelength near infrared light source. It is found that the optimal external quantum efficiency of the device can reach 2.52; the stability of the device is good; simply changing the quantum dot size can change the emission wavelength of the device. 2. Single wavelength Pb se quantum dot light emitting diode is used as light source to detect acetylene gas. The chemical reaction between some gases and the surface of the quantum dot changes the fluorescence spectrum of the quantum dot, such as fluorescence quenching, fluorescence intensity decreasing, etc. So now most of the work of using quantum dots to detect gases is based on this characteristic of quantum dots. However, the sensitivity of this method is not high, at the same time, there are still many problems in practical application. For this reason, we have developed a new method of detecting the gas by using subpoints, that is, using Pb se quantum dot near infrared light source as the detection source, and using direct absorption spectrometry to detect acetylene gas. The detection limit of the detection system is 20 ppm, and the detection accuracy is 2. 3. 3. Multi-wavelength Pb se quantum dot light emitting diode is used as the detection light source for simultaneous detection of various gases. Three PbSe quantum dots of different sizes were integrated into a gan LED chip to fabricate a near infrared light source with three wavelengths of 1526 ~ 1676 ~ 1948 nm. Using this light source as detection source, methane, acetylene and ammonia were detected simultaneously by direct absorption spectrometry. The detection limit is 100 ~ 20 ~ 20ppm and the detection precision is 2, which achieves the purpose of simultaneous detection of multi-gas. A multi-wavelength Pb se quantum dot light-emitting diode (QDs), which can be modulated separately, is used as the detection light source, and the differential absorption method is used to detect the two gases simultaneously. We choose a gan light-emitting diode with three independent chips as the excitation source. The three chips have independent electrodes and can be modulated separately. Three kinds of PbSe quantum dots of different sizes were integrated on three chips to produce a near infrared light source with three wavelengths modulating respectively. We used this light source to detect acetylene and ammonia simultaneously by differential absorption method. The difference spectrum method can eliminate the error caused by the instability of the light source. In order to simplify the detection system, we replaced the spectrometer with photodetectors and cut the optical path length by half. Finally, the detection limits of acetylene and ammonia are 25 and 30 ppm, respectively, and the detection error is less than 2 parts.
【学位授予单位】：吉林大学
【学位级别】：博士
【学位授予年份】：2016
【分类号】：TN312.8

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