Colour tuning in white hybrid inorganic/organic light-emitting diodes
Colour tuning in white hybrid inorganic/organic light-emitting diodes
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DOI：
10.1088/0022-3727/49/40/405103
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发表时间：
2016-10
期刊：
影响因子：
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通讯作者：
J. Bruckbauer;Catherine G. Brasser;N. Findlay;P. Edwards;D. Wallis;P. Skabara;R. Martin
中科院分区：
文献类型：
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作者：
J. Bruckbauer;Catherine G. Brasser;N. Findlay;P. Edwards;D. Wallis;P. Skabara;R. Martin
将一种新型的有机颜色转换器与蓝色无机发光二极管（LED）相结合，制备了白色无机/有机混合发光二极管（LED）。一种有机小分子是专门合成的，作为降频转换器。白色颜色的特征通过改变基于BODIPY单元的有机分子的浓度以及分子和密封剂混合物的体积来控制，所述BODIPY单元嵌入透明基质中。浓度对转换效率有关键影响，即吸收的蓝光中有多少被转换成黄光。随着浓度的增加，转换效率降低。这种猝灭效应是由于有机分子在较高浓度下的聚集。增加转换器的沉积量不会增加黄光发射，尽管吸收了更多的蓝光。在LED制造的15个月期间也观察到有机转换器的退化。角度依赖性测量揭示了蓝色和黄色发射峰的朗伯曲线的轻微偏差，导致“白度”随发射角的小变化。使用不同浓度的转换分子，分别实现了相关色温为2770 K和7680 K的暖白色和冷白色光。虽然需要进一步的工作来改善寿命和较差的显色性，但是与基于磷光体的白色LED相比，这些混合LED显示出作为用于生成白色LED的替代方法的有希望的结果。
White hybrid inorganic/organic light-emitting diodes (LEDs) were fabricated by combining a novel organic colour converter with a blue inorganic LED. An organic small molecule was specifically synthesised to act as down-converter. The characteristics of the white colour were controlled by changing the concentration of the organic molecule based on the BODIPY unit, which was embedded in a transparent matrix, and volume of the molecule and encapsulant mixture. The concentration has a critical effect on the conversion efficiency, i.e. how much of the absorbed blue light is converted into yellow light. With increasing concentration the conversion efficiency decreases. This quenching effect is due to aggregation of the organic molecule at higher concentrations. Increasing the deposited amount of the converter does not increase the yellow emission despite more blue light being absorbed. Degradation of the organic converter was also observed during a period of 15 months from LED fabrication. Angular-dependent measurements revealed slight deviation from a Lambertian profile for the blue and yellow emission peaks leading to a small change in ‘whiteness’ with emission angle. Warm white and cool white light with correlated colour temperatures of 2770 K and 7680 K, respectively, were achieved using different concentrations of the converter molecule. Although further work is needed to improve the lifetime and poor colour rendering, these hybrid LEDs show promising results as an alternative approach for generating white LEDs compared with phosphor-based white LEDs.