碳点-纤维素复合红色发光材料制备及性能

Preparation and Properties of Carbon Dots-cellulose Composite Red Emitting Phosphors

白光LED器件作为新一代绿色固态照明光源,已广泛应用于照明、液晶背光等领域,也与智能照明、物联网技术等高新科技产业密切相关。常用的蓝光芯片复合黄光YAG∶Ce^(3+)(Y 3Al 5O 12∶Ce^(3+))荧光粉的白光器件由于缺少红色光谱的成分,导致器件光谱较窄,显色指数较低,色温偏高。因此,红色荧光粉对改善白光LED的光色品质起到了重要作用。本文首先制备了红色碳点(量子效率28%),通过把红色碳点与纤维素复合,制备了红色荧光粉(量子效率为18%)。该红色荧光粉与黄光YAG∶Ce^(3+)荧光粉混合,封装得到暖白光。结果表明,相较于只有黄光YAG∶Ce^(3+)荧光粉封装的LED,红色荧光粉掺杂之后,在460 nm蓝光芯片的激发下,白光LED的色坐标由(0.30,0.33)变化到(0.33,0.35),色温从7396 K下降到5714 K,显色指数从78.2升高到82.9,实现了由色温高、显示指数低的冷白光向色温低、显色指数高的暖白光的调节。

As a new generation of green solid-state lighting source,white light-emitting diode(LED)devices not only have been widely used in lighting,liquid crystal display(LCD)backlighting and other fields,but also are related to intelligent lighting,the Internet of Things technology and other high-tech industries.White light devices consisting of yellow emitting YAG∶Ce^(3+)(Y 3Al 5O 12∶Ce^(3+))phosphors and blue chip are commonly used but lacking the components of red spectrum,resulting in the device s narrow spectrum,low color rendering index(CRI)and high correlated color temperature(CCT).Therefore,red phosphors play an important role in improving the color quality of white LED.Herein,red carbon dots with 28%quantum yield(QY)are synthesized and then combined with cellulose to form red phosphors(QY≈18%).Red phosphors are mixed with commercial YAG∶Ce^(3+)(Y 3Al 5O 12∶Ce^(3+))to obtain warm white LED.Compared to the LED encapsulated with YAG∶Ce^(3+)phosphors,the CIE color coordinate of the LED which is encapsulated with YAG∶Ce^(3+)phosphors and red phosphors changes from(0.30,033)to(0.33,0.35),the CCT declines from 7396 K to 5714 K and the CRI raises from 78.2 to 82.9 under the excitation of 460 nm emitting blue chip.It achieves that cold white light-emitting diodes(WLED)with high CCT and low CRI were adjusted to warm WLED with low CCT and high CRI.