Key Laboratory of Chemical Biology and Traditional Chinese Medicine Research (Ministry of Education of China) and Key Laboratory of Sustainable Resources Processing and Advanced Materials of Hunan Province College , Hunan Normal University , Changsha 410081 , China.
School of Chemistry and Chemical Engineering , Hunan Institute of Engineering , Xiangtan 411104 , China.
Inorg Chem. 2019 Oct 7;58(19):13481-13491. doi: 10.1021/acs.inorgchem.9b02555. Epub 2019 Sep 24.
Photoluminescence quantum efficiency (QE) and thermal stability are important for phosphors used in phosphor-converted light-emitting diodes (pc-LEDs). Hydroxyapatite, Ca(PO)OH, is generally not used as host for phosphors, because the OH group in the host will lead to a high vibrational frequency around the activators and reduces the luminescent efficiency or even quenches the emission. In this work, strong blue emission at 450 nm appears after introducing boron atoms into Ce-doped hydroxyapatite under excitation of a UV light. Analyses suggest that B atoms enter into the host structure, which lead to the modification of crystal structure and the formation of vacancies of O and H to compensate charge mismatch. The decrease of OH groups around Ce ion on Ca (3) site is responsible for the appearance of strong blue emission. The absolute QE value of the best blue-emitting phosphor is ∼92%, and the emission intensity at 150 °C remains 81% of that at room temperature. The emission peak and International Commission on Illumination (CIE) coordinates hardly change upon increasing temperature. The results suggest that boron-modified hydroxyapatite phosphor could be a candidate for UV-LED-pumped white phosphor-converted LEDs. This strategy may provide a new insight into the exploration of phosphors' hosts and other functional materials.
光致发光量子效率（QE）和热稳定性对于用于荧光粉转换发光二极管（pc-LED）的荧光粉很重要。羟基磷灰石，Ca(PO)OH，通常不作为荧光粉的基质使用，因为基质中的 OH 基团会导致激活剂周围的振动频率很高，从而降低发光效率，甚至猝灭发射。在这项工作中，在紫外光激发下，硼原子被引入 Ce 掺杂的羟基磷灰石后，会出现 450nm 处的强蓝色发射。分析表明，B 原子进入到宿主结构中，这导致了晶体结构的修饰和 O 和 H 空位的形成，以补偿电荷失配。在 Ca(3)位上 Ce 离子周围的 OH 基团的减少是出现强蓝色发射的原因。最佳蓝色发射荧光粉的绝对 QE 值约为 92%，在 150°C 时的发射强度保持室温时的 81%。随着温度的升高，发射峰和国际照明委员会（CIE）坐标几乎没有变化。结果表明，硼修饰的羟基磷灰石荧光粉可能是 UV-LED 激发的白色荧光粉转换 LED 的候选材料。该策略可能为荧光粉基质和其他功能材料的探索提供新的思路。
