【摘要】 采用改进的坩埚下降法成功地生长了Tm/Yb共掺氟化钇锂单晶.该单晶体具有每吸收一个蓝色光子并能发射出2个1000 nm近红外光子的下转换发光效应.测定了样品的激发光谱、发射光谱和荧光衰减曲线.在465 nm蓝光激发下观察到由Yb³⁺:²F_5/2→²F_7/2能级跃迁所致的960¹050 nm波段的发射带,此发光带源于Tm³⁺对Yb³⁺离子的能量下转换过程.应用Inokuti-Hirayama模型,研究了晶体的能量转换过程,结果 表明Tm³⁺向Yb³⁺的能量传递是一个电偶极子相互作用机制过程.当Tm³⁺与Yb³⁺离子的掺杂浓度为0.49mol%与5.99mol%时,单晶的量子剪裁效率达到最大值167.5%.更多还原

【Abstract】 Downconversion（DC） with emission of two near-infrared photons about 1000 nm for each blue photon absorbed was obtained in thulium(Tm³⁺) and ytterbium(Yb³⁺) codoped yttrium lithium fluoride（L1YF4） single crystals grown by an improved Bridgman method.The luminescent properties of the crystals were measured through photoluminescence excitation,emission spectra and decay curves.Luminescence between 960 and 1050 nm from Yb³⁺:²F_5/2→²F_7/2 transition,which was originated from the DC from Tm³⁺ ions to Yb³⁺ ions,was observed under the excitation of blue photon at 465 nm.Moreover,the energy transfer processes were studied based on the Inokuti-Hirayama model,and the results indicated that the energy transfer from Tm³⁺ to Yb³⁺ was an electric dipole-dipole interaction.The maximum quantum cutting efficiency approached up to 167.5%in LiYF₄ single crystal codoped with 0.49mol%Tm³⁺ and 5.99mol%Yb³⁺.Application of this crystal has prospects for increasing the energy efficiency of crystalline Si solar cells by photon doubling of the high energy part of the solar spectrum.更多还原