Ce,Gd∶YAG单晶复合K_2SiF_6∶Mn^(4+)红色荧光粉的制备及其光电性质的研究

Preparation and Optoelectronic Properties of Ce,Gd∶ YAG Single Crystal Compounded with K_2SiF_6∶Mn^(4+) +Red Phosphor

采用提拉法生长共掺Ce和Gd的钇铝石榴石单晶(Ce,Gd∶YAG),开展了白光LED用新型YAG单晶复合K_2SiF_6∶Mn^(4+)荧光粉材料的制备和光谱性能研究。检测到Ce,Gd∶YAG单晶在激发波长为460 nm处有强烈的激发带,可证实存在能量传递。发现当Y^(3+)部分被Gd3+取代后,发射峰向长波长方向移动。研究了Ce∶YAG单晶厚度的变化对其色坐标、亮度、发光效率和色温的影响,发现Ce,Gd∶YAG单晶制备的LED器件发光中红光成分还是不够。为了缓解白光LED用Ce,Gd∶YAG单晶仍然缺少红光的问题,采用丝网印刷法将红色荧光粉K_2SiF_6∶Mn^(4+)印刷在Ce,Gd∶YAG单晶衬底上制备白光LED。研究了不同含量的K_2SiF_6∶Mn^(4+)红色荧光粉对其色坐标、亮度、发光效率和色温的影响。研究发现,随着含量的增加,器件的发光由冷白光逐渐向暖白光区域移动,色温有所降低,显色指数上升。Ce,Gd∶YAG单晶复合红色荧光粉的思路可以对LED照明发暖白光有所参考。

Ce,Gd∶YAG single crystal was grown by Czochralski method,and the compounds of Ce,Gd∶YAG single crystal and K2SiF6∶Mn^4＋＋for white light emitting diode was developed to study the preparation and spectral performance. Excitation spectra collected at Ce,Gd ∶ YAG single crystal shows an intense excitation at 460 nm, which is confirmed the energy transfer. The launch peak moves in a long wavelength direction when the Y^3＋were replaced by Gd^3＋. Additionally,we found that the lack of red light in the LED device based on the Ce,Gd∶ YAG single crystal when studied the different thicknesses of Ce,Gd∶ YAG single crystal on the color coordinates,luminance,luminous efficacy and correlated color temperature. In order to alleviate the problem of red light,the red fluorescent powder K2SiF6∶Mn^4＋ ＋were printed in Ce,Gd ∶ YAG single crystal substrate by screen-printing technology. As the red phosphor concentrations increasing,the chrominance of the white LED shift from cool light to warm light area,correlated color temperature gradually reduced and color rendering index gradually rised. Those results demonstrate that the developed red phosphor coated on Ce,Gd ∶ YAG single crystal has potential applications for high-power white LED.