Here, we report that a reduction in scale leads to an enhancement in the photoluminescence (PL) of Eu³⁺ doped BiOCl nanosheets, challenging the long-standing notion that PL is inevitably suppressed at a scale of tens of nanometers. The oriented depolarization effect of layered ferroelectrics was utilized for the first time to improve the PL efficiency of lanthanide doped nanomaterials. The probing effect of the electric dipole transitions of the Eu³⁺ ions and their PL measurements provides evidence that the depolarization field and the PL of Eu³⁺ ions increase synchronously as the thickness of the BiOCl single-crystalline nanosheets decreases from hundreds to tens of nanometers. We show that the scale-dependent internal electric field (IEF) induced by the depolarization field as well as its excitation field enhancement are responsible for the appearance of an abnormal scale-dependent PL enhancement. This finding may be useful for the development of low-dimensional material systems with enhanced photophysical properties, relevant for use in new nano-optoelectronic devices.

中文翻译：

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在减小的垂直尺寸 下出现了Eu ³⁺掺杂的BiOCl单晶纳米片增强光致发光的现象†

在这里，我们报道规模减小导致Eu ³⁺掺杂的BiOCl纳米片的光致发光（PL）增强，挑战了长期存在的观念，即PL不可避免地被抑制在几十纳米的规模。首次利用层状铁电体的定向去极化作用来提高掺杂镧系元素的纳米材料的PL效率。中的Eu的电偶极跃迁的探测效果³⁺离子及其PL测量提供的证据表明去极化场和Eu的PL ³⁺随着BiOCl单晶纳米片的厚度从数百纳米减小到数十纳米，离子同步增加。我们表明，由去极化场及其激发场增强引起的比例依赖的内部电场（IEF）负责异常比例依赖的PL增强的出现。该发现对于开发具有增强的光物理性质的低维材料系统可能是有用的，这与在新的纳米光电装置中使用有关。