Aluminum nanocrystals (Al NCs) are sustainable plasmonic nanomaterials with unique localized surface plasmonic resonance (LSPR) in the ultraviolet (UV) region. Chemical synthesis of sub-100-nm Al NCs remains a considerable challenge due to the lack of effective ligands to control their growth. Here, we describe a precise size-controlled synthesis of small colloidal Al NCs (25–100 nm) with strong and tunable LSPR peak from 250 to 372 nm in the UV spectral region by the use of poly(ethylene oxide) (PEO) as a polydentate surface ligand. The LSPR band matched well with the numerical simulation results. Additionally, the molecular weight of the PEO played an essential role in tuning the size of Al NCs. The PEO showed a strong affinity with Al {111} crystal facets, resulting in octahedral- and prism-shaped Al NCs. Owing to the passive oxide layer generated on the surface of Al NCs, their LSPR peak positions showed negligible changes after storage in tetrahydrofuran for 4 months. The passivation layer also impeded the metal Al core to react with deionized water. Further, the use of biocompatible PEO ligand and the subsequent generation of the sub-100-nm size of the Al NCs pave a path for bioapplications of such NCs.

中文翻译：

---

聚环氧乙烷介导的用于深紫外等离子体纳米材料的100 nm以下纳米铝晶体的合成

铝纳米晶体（Al NCs）是可持续的等离子体纳米材料，在紫外线（UV）区域具有独特的局部表面等离子体共振（LSPR）。由于缺乏有效的配体来控制其生长，因此亚100 nm Al NCs的化学合成仍然是一个巨大的挑战。在这里，我们描述了通过使用聚环氧乙烷（PEO）作为UV光谱区域中250至372 nm的强且可调LSPR峰的小型胶体Al NCs（25–100 nm）的精确尺寸控制合成。多齿表面配体。LSPR频带与数值模拟结果非常吻合。此外，PEO的分子量在调整Al NCs的尺寸方面起着至关重要的作用。PEO显示出与Al {111}晶面的强亲和力，从而产生八面体和棱柱形的Al NC。由于在Al NCs表面产生的钝化氧化物层，在四氢呋喃中保存4个月后，其LSPR峰位置的变化可忽略不计。钝化层还阻止金属铝芯与去离子水反应。此外，生物相容性PEO配体的使用以及随后产生的Al NCs的小于100nm尺寸为此类NCs的生物应用铺平了道路。