Towards OCPLEDs: Organic Circularly Polarised Light Emitting Devices

有机发光二极管(OLED)需要位于两个电极之间的有机半导体材料的发光层，其中至少一个电极是透明的。这种设备正在给显示技术带来革命性的变化，使生产灵活且完全透明的设备成为可能。圆偏振电致发光(CPEL)器件在高性能的LCD背光、彩色图像探测和立体显示、光通信和量子计算等光子技术领域具有巨大的应用潜力，但直接产生CPEL的问题至今尚未得到解决。本研究的目的是利用本征的手性、导电性和发光性小分子作为有机发光器件的电致发光层，试图展示高效的共面发光。这类工作将对现有知识产生重大影响，这些知识可在若干翻译领域加以利用。以替代LCD背光为例，当前的技术依赖于偏振滤光片，这种滤光片有效地切断了这些显示器中使用的75%的光。再加上滤色器和设备接口处的吸收，只有4%的所用光被透过。使用偏振光源，再加上可调的颜色成分，将消除这一需求，从而显著提高显示器的能效，显著降低碳足迹。

Organic light emitting diodes (OLEDs) require an emissive electroluminescent layer of an organic semiconductor material located between two electrodes, where at least one of the electrodes is transparent. Such devices are revolutionising display technologies, with the production of flexible and fully transparent devices possible. Devices that emit circularly polarised electroluminescence (CPEL) should have vast translational potential in photonic technology, such as highly improved LCD backlighting, colour-image detection and stereoscopic displays, optical communication, and quantum computing, however to date the problem of directly generating CPEL has not been solved. The goal of this research is to use intrinsically chiral, conductive and luminescent small molecules as electroluminescent layer in OLEDs, in an attempt to demonstrate efficient CPEL. Such work would have significant impact on current knowledge, which could be exploited in a number of translational areas. Taking alternative LCD backlighting as one example of the exploitation of this work, current technologies rely on polarising filters that effectively cut out 75% of the light used in these displays. Combined with absorption by the colour filters and at device interfaces, only 4% of the light used is transmitted. The use of a polarised light source, coupled with tuneable colour components would remove this need, thus leading to significantly more energy efficient displays, with a dramatically lowered carbon footprint.