A series of Er³⁺‐doped magnesium aluminium layered double hydroxides (Er³⁺‐doped, MgAl‐LDHs) with different Mg²⁺/(Al³⁺+Er³⁺) molar ratios were synthesized using the hydrothermal method. Compositional and structural analyses suggest that the Er³⁺‐doped MgAl‐LDHs kept a hexagonal structure while the Mg²⁺/(Al³⁺+Er³⁺) molar ratio was at 1.0–4.1. The downconverted emission spectra of the Er³⁺‐doped MgAl‐LDHs showed a red emission at 650 nm and strong infrared emissions at 720, 780, and 850 nm. These infrared emissions were hardly observed in previous downconverted emission spectra of Er³⁺‐doped materials. In the analysis of the Er³⁺ energy levels and in relevant published literature, the energy transfer diagram for Er³⁺‐doped in MgAl‐LDHs is described, and infrared emissions at 720, 780, and 850 nm may be attributed to ⁴F_7/2→⁴I_13/2, ²H_11/2→⁴I_13/2, and ⁴S_3/2→⁴I_13/2 transitions of Er³⁺, respectively. Er³⁺‐doped MgAl‐LDHs could have potential application as marking and targeting agents in the processes for drug delivery in consideration of the strong near‐infrared Er³⁺emissions, as well as the special layered structure of MgAl‐LDH.

中文翻译：

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掺Er3 +的MgAl层状双氢氧化物的新近红外发射和能量转移。

使用水热法合成了一系列摩尔比不同的Mg ²⁺ /（Al ³⁺ + Er ³⁺）的Er ³⁺掺杂的镁铝层状双氢氧化物（Er ³⁺掺杂的MgAl-LDHs）。成分和结构分析表明，掺Er ^3+的MgAl-LDHs保持六方结构，而Mg ²⁺ /（Al ³⁺ + Er ³⁺）的摩尔比为1.0-4.1。Er ³⁺的下转换发射光谱掺杂的MgAl-LDHs在650 nm处显示红色发射，在720、780和850 nm处显示强烈的红外发射。在先前的Er ³⁺掺杂材料的下变频发射光谱中几乎没有观察到这些红外发射。在对Er ³⁺能级的分析和相关的公开文献中，描述了掺在MgAl-LDHs中的Er ³⁺的能量转移图，并且720、780和850 nm处的红外发射可能归因于⁴ F _7/2 → ⁴我_13/2，² ħ _11/2 → ⁴我_13/2，和⁴ š _3/2 → ⁴予Er ^3+的_13/2跃迁。考虑到强烈的近红外Er ³⁺排放以及MgAl-LDH的特殊分层结构，掺Er ^3+的MgAl-LDHs可能在药物输送过程中作为标记和靶向剂。