Highly color-stable solution-processed multilayer WOLEDs for lighting application
Highly color-stable solution-processed multilayer WOLEDs for lighting application
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DOI：
10.1039/b924968k
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发表时间：
2010-04
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通讯作者：
Anne Köhnen;Mayra Irion;M. Gather;Nina Rehmann;P. Zacharias;K. Meerholz
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文献类型：
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作者：
Anne Köhnen;Mayra Irion;M. Gather;Nina Rehmann;P. Zacharias;K. Meerholz
白色有机发光器件，特别是聚合物发光器件（WPLED）由于其提供成本有效且制造简单的固态光源的潜力而受到特别关注。国际照明委员会（CIE）坐标的最大可接受变化通常被规定为Δ x，y <0.01，用于一般照明目的，甚至被汽车工业规定为Δ x，y <0.005。在过去的几年中，关于OLED的颜色稳定性已经取得了很大的进展。在第一批出版物中报道了大约Δ x，y = 0.2，0.1的大色移。目前的出版物提出了具有小至Δ x，y = 0.02、0.02或更好的CIE变化的器件，甚至对于聚合物OLED也是如此。在这里，我们提出了一个高度颜色稳定的白色荧光多层OLED组成的两层（黄色EML/蓝色EML）堆栈。器件显示出白色发射，CIE值为0.324、0.346。由于其电子和空穴分布非常平衡，这些器件在100和10 000 nit之间的CIE值（± 0.009，0.006）几乎没有变化。该范围内的亮度可以在低电压（4 - 8 V）下获得，同时提供6 cd A − 1的高效率。此外，由于发射的宽光谱宽度，该器件表现出84的显色指数。该值符合环境照明的实际要求。在初始亮度为100 cd m − 2时，外推的半亮度寿命超过1000 h。所有系统都包括光化学或热交联每层，以实现溶液处理的复杂多层OLED结构。
White organic and especially polymeric light emitting devices (WPLEDs) have received particular attention due to their potential to provide cost-effective and simply manufactured solid-state light sources. The largest acceptable variation of Commission Internationale de L'Eclairage (CIE) coordinates is typically specified as Δx,y < 0.01 for general illumination purposes and even down to Δx,y < 0.005 by the automotive industry. Over the last few years great progress has been made regarding color-stability of OLEDs. In the first publications large color shifts of about Δx,y = 0.2,0.1 were reported. Current publications present devices with CIE variations as small as Δx,y = 0.02,0.02 or better, even for polymeric OLEDs. Here, we present a highly color-stable white fluorescent multilayer OLED consisting of a two-layer (yellow EML/blue EML) stack. The devices show white emission with CIE values of 0.324,0.346. Because of their extremely well-balanced electron and hole distribution, these devices show nearly no change in their CIE values (± 0.009,0.006) between 100 and 10 000 nits. Brightness in that range can be obtained at low voltages (4–8 V), at the same time providing a high efficiency of 6 cd A−1. In addition, due to the broad spectral width of the emission the devices exhibit a color rendering index of 84. This value complies favourably with actual demands for ambient lighting. The extrapolated half-brightness lifetime at an initial brightness of 100 cd m−2 exceeds 1000 h. All systems include the crosslinking of each layer either photo-chemically or thermally to enable the solution-processed complex multilayer OLED-structures.