采用高温固相法制备了系列的荧光粉样品:Ca₂GdSbO₆∶xMn⁴⁺(x=0.001～0.006)和Ca₂GdSbO₆∶0.003Mn⁴⁺,yF^-(y=0.001～0.006)。X射线衍射(XRD)测试结果表明,少量Mn⁴⁺和F^-的掺杂没有改变Ca₂GdSbO₆材料的晶体结构。在330nm的激发下,Ca₂GdSbO₆∶Mn⁴⁺荧光粉的发射光谱呈现一个峰值为675nm的宽发射带,属于Mn⁴⁺的 ²E_g→⁴A_2g能级跃迁。在675nm监测下,荧光粉的最强激发峰位于330nm,属于 ⁴A_2g→⁴T_1g能级跃迁,还有一个位于265nm的肩峰归属于O^2-→Mn⁴⁺电荷转移带。Ca₂GdSbO₆∶xMn⁴⁺(x=0.001～0.006)样品的荧光发射光谱数据表明,Mn⁴⁺的最佳掺杂量x为0.003。Ca₂GdSbO₆∶0.003Mn⁴⁺,yF^-(y=0.001～0.006)的光谱数据表明,电荷补偿后的荧光粉样品相比于没有掺F^-的样品,其发光强度、荧光寿命以及热稳定性都有所提升,原因是Mn⁴⁺异价取代Sb⁵⁺产生的氧空位会捕获发光中心并抑制发光,而引入与O^2-离子半径相近的F^-作为电荷补偿剂可有效填补氧空位、减少晶格缺陷、降低声子能量并提高辐射跃迁概率。综上,Ca₂GdSbO₆∶Mn⁴⁺荧光粉是一种可用于植物生长的红色LED发光材料,通过F^-的电荷补偿,可很好地改善材料的发光性能。

A series of phosphor samples were prepared via high-temperature solid-state method:Ca₂GdSbO₆∶xMn⁴⁺(x=0.001 to 0.006) and Ca₂GdSbO₆∶0.003Mn⁴⁺,yF^-(y=0.001 to 0.006).X-ray diffraction (XRD) test results indicated that the doping of a small amount of Mn⁴⁺ and F^- did not alter the crystal structure of the Ca₂GdSbO₆ material.Under 330nm excitation,the emission spectrum of the Ca₂GdSbO₆∶Mn⁴⁺ phosphor exhibited a broad emission band with a peak at 675nm,corresponding to the energy level transition of Mn⁴⁺ from ²E_g to ⁴A_2g.When monitored at 675nm,the strongest excitation peak of the phosphor was located at 330 nm,corresponding to the energy level transition from ⁴A_2g to ⁴T_1g,with an additional shoulder peak at 265nm,indicating a charge transfer band between O^2- and Mn⁴⁺.The fluorescence emission spectral data of the Ca₂GdSbO₆∶xMn⁴⁺(x=0.001 to 0.006) samples suggested that the optimal doping amount of Mn⁴⁺ was x=0.003.The spectral data for Ca₂GdSbO₆∶0.003Mn⁴⁺,yF^-(y=0.001 to 0.006) indicated that the luminescence intensity,fluorescence lifetime,and thermal stability of the phosphor samples were improved after charge compensation compared to the samples without F^- doping.This improvement stemmed from the oxygen vacancies generated by substitution of Mn⁴⁺ for Sb⁵⁺,which could capture luminescent centers and suppress luminescence.Introducing F^- ions with ionic radii similar to O^2- as charge compensators effectively filled oxygen vacancies,reduced lattice defects,decreased phonon energy,and increased radiative transition probability.In summary,the Ca₂GdSbO₆∶Mn⁴⁺ phosphor was a red LED luminescent material suitable for plant growth,and its luminescent properties could be significantly improved through F^- charge compensation.