摘要:
本文采用固相法在500?C合成了Er3+/Eu3+共掺BiOCl 荧光粉,并通过XRD, SEM,吸收,激发和发射光谱研究了其结构、形貌和发光特性。 XRD和SEM结果表明在500?C下即可成功合成纯四方相片层结构的Er3+/Eu3+共掺BiOCl荧光粉。吸收光谱表明掺杂Er3+/Eu3+离子使BiOCl形成杂质能级；激发光谱显示该荧光粉具有来自于基质BiOCl价带(VB)到导带(CB)跃迁的优异宽带近紫外激发特性。在380 nm近紫外光激发下,同时获得了Er3+离子和Eu3+离子的特征发射峰,其中发光中心位于410 nm (2H9/2→4I15/2),525 nm (2H11/2→4I15/2),554 nm (4S3/2→4I15/2),673 nm (4F9/2→4I15/2)的发射峰来自于Er3+离子的跃迁,而581 nm (5D0→7F0),594 nm (5D0→7F1),622 nm (5D0→7F2),653 nm (5D0→7F3),699 nm (5D0→7F4)的发射峰则来自于Eu3+离子的跃迁。值得注意的是,与传统Er3+/Eu3+掺杂的材料不同,该荧光粉还具有独特高效的紫光(Er3+)和长波红光(Eu3+)发射特性,分析表明这与BiOCl的结构有关；并且通过改变掺杂浓度,实现了发光颜色由黄绿光→黄光→橙红光的调节。研究结果表明Er3+/Eu3+共掺BiOCl荧光粉有望成为一种潜在的近紫外激发白光LED荧光粉。
Abstract:
In this paper, Er3+/Eu3+ co-doped BiOCl phosphors are synthesized by the conventional solid state method at 500?C, which are characterized by XRD, SEM, absorption spectra, excitation spectra and emission spectra. XRD analysis indicates that the samples exhibit pure tetragonal phase BiOCl. In SEM pictures, the samples exhibit smooth plate-like particles. The absorption spectra indicate that Er3+/Eu3+ ion dopants result in an impurity energy level, and the excitation spectra show that the sample has excellent broadband near ultraviolet (NUV)-exciting ability, which is due to the electronic transitions of the BiOCl bandgap. Under at 380 nm excitation, the emission bands located at 410 nm (2H9/2 →4I15/2), 525 nm (2H11/2 →4I15/2), 554 nm (4S3/2 →4I15/2), 673 nm (4F9/2 →4I15/2) of Er3+ ions, and 581 nm (5D0 →7F0), 594 nm (5D0 →7F1), 622 nm (5D0 →7F2), 653 nm (5D0 →7F3), 699 nm (5D0 →7F4) of Eu3+ ions can be observed, respectively. Moreover, contrary to most of the Er3+/Eu3+-activated phosphors, the Er3+/Eu3+ co-doped BiOCl phosphor shows the unique and effective emission of the violet (Er3+) and far-red (Eu3+), which results from the particular structure of BiOCl crystals. The tunability in color of emitted radiation has been visualized by using chromaticity diagram on changing the doping concentration. Results show that the Er3+/Eu3+ co-doped BiOCl is a promising phosphor for near UV white LEDs.
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