Lanthanide doped upconversion nanocrystals with remarkable optical properties have been utilized for many emerging applications. Here, solid solution Na(Gd_xLa_1-x)(MoO₄)₂ nanocrystals are synthesized hydrothermally, and their upconversion photoluminescent and photothermal properties as luminescent host matrix for Yb³⁺/Er³⁺ activators are systematically studied. The effect of La³⁺ doping content on the phase, crystal structure, upconversion luminescence and photothermal conversion are investigated. Rietveld refinements based on XRD data indicate that La³⁺ occupy Gd³⁺ sites substitutionally, and pure phase solid solution Na(Gd_xLa_1-x)(MoO₄)₂ is formed. Due to lattice distortion, lower lanthanide site symmetry and augmented odd-parity crystal field interactions after La³⁺ doping, the 4f-4f transition probabilities of the lanthanide ions are effectively increased. Na(Gd/La)(MoO₄)₂ solid solution hosts exhibit enhanced upconversion luminescence from Er³⁺/Yb³⁺, compared with single-component NaGd(MoO₄)₂ counterparts. What's more, based on the calculated temperatures of the samples derived from the luminescence intensity ratio of states ²H_11/2 and ⁴S_3/2 for Er³⁺, enhanced photothermal conversion efficiency is speculated in solid solution Na(Gd_xLa_1-x)(MoO₄)₂:Yb³⁺/Er³⁺ nanocrystals, which is further confirmed by infrared thermographic images. The underling mechanisms of simultaneously enhanced photothermal effects and luminescence intensity in Na(Gd_xLa_1-x)(MoO₄)₂ solid solution nanocrystals are elucidated. Modulation of composition in solid solution hosts may be an effective method for combating luminescent thermal quenching and/or regulating photothermal conversion and photoluminescence properties simultaneously. Multifunctional solid solution upconversion nanocrystals could be potential for photoluminescent and photothermal applications.

具有显着光学特性的镧系元素掺杂上转换纳米晶体已被用于许多新兴应用。在这里，水热法合成了固溶体Na(Gd _x La _{1- x} )(MoO ₄ ) ₂纳米晶体，并系统地研究了它们作为Yb ³⁺ /Er ³⁺活化剂的发光基质的上转换光致发光和光热性能。研究了La ³⁺掺杂量对相、晶体结构、上转换发光和光热转换的影响。基于 XRD 数据的 Rietveld 细化表明 La ³⁺占据 Gd ³⁺位取代，形成纯相固溶体Na(Gd _x La _{1- x} )(MoO ₄ ) ₂。由于 La ³⁺掺杂后的晶格畸变、较低的镧系元素位点对称性和增强的奇数奇偶晶场相互作用，镧系离子的 4 f -4 f跃迁概率有效增加。与单组分 NaGd(MoO ₄ ) ₂相比，Na(Gd/La)(MoO ₄ ) ₂固溶体主体表现出来自 Er ³⁺ /Yb ^{3+ 的}增强的上转换发光同行。此外，根据由Er ^{3+ 的2} H _11/2和⁴ S _3/2态的发光强度比得出的样品的计算温度，推测在固溶体 Na(Gd _x La _{1 - x} )(MoO ₄ ) ₂ :Yb ³⁺ /Er ³⁺纳米晶体，红外热成像图像进一步证实了这一点。Na(Gd _x La _{1- x} )(MoO ₄) _{2 个}固溶体纳米晶体被阐明。调节固溶体主体中的成分可能是一种有效的方法，可以同时对抗发光热猝灭和/或调节光热转换和光致发光特性。多功能固溶体上转换纳米晶体可能具有光致发光和光热应用的潜力。