采用溶胶-凝胶法制备了纯的和Mg2+-Ni2+掺杂的LaFeO3, 并对它们在近红外波段的发射率进行了研究和比较。结果表明, 34%(摩尔分数)的Mg2+和23%(摩尔分数)的Ni2+掺杂的LaFeO3即LaMg0.34Ni0.23Fe0.43O3在0.2~2 μm波段的红外发射率达到了0.966, 远高于未掺杂LaFeO3的0.446。Mg2+-Ni2+共掺杂能够显著提高LaFeO3在近红外波段的发射率的原因在于Mg2+、Ni2+进入铁酸镧的晶格中取代Fe3+, 引入了杂质能级, 氧空位浓度增加, 提高了杂质能级吸收以及氧空位吸收, 掺杂引起的晶格畸变使得晶格振动吸收增强; 此外, 电子在Fe3+和Fe4+之间的极化跃迁, 也增强了化合物在相应光谱区域的吸收性能。

Pure and Mg2+-Ni2+ doped LaFeO3 were prepared by sol-gel method, and their emission rates in the near infrared band were studied and compared. The results show that the infrared emission rate in 0.2-2 μm waveband of LaMg0.34Ni0.23Fe0.43O3 (Mg2+ mole fraction of 34%, Ni2+ mole fraction of 23%) is 0.966, much higher than that of undoped LaFeO3(0.446). For Mg2+-Ni2+ co-doped LaFeO3, Mg2+, Ni2+ come into lanthanum ferrite lattice to substitute Fe3+, which introduces the impurity levels and increases the oxygen vacancy concentration. The impurity energy absorption and absorption of oxygen vacancies are improved, and the lattice distortion induced by doping makes the lattice vibration absorption enhance. In addition, the polarized transition of electrons between Fe3+ and Fe4+ greatly enhances the absorption performance of the compounds in the corresponding spectra. So, Mg2+-Ni2+ co-doping can significantly improve the infrared emission rate of LaFeO3.