Abstract Newly explored two-dimensional (2D) materials have shown promising optical properties, owning to the tunable band gap of the layered material with its thickness. A widely used method to achieve tunable light emission (or photoluminescence) is through thickness modulation, but this can only cover specific wavelengths. This approach limits the development of tunable optical devices with high spectral resolution over a wide range of wavelengths. Here, we report wideband tunable light emission of exfoliated black phosphorus nanosheets via a pulsed thermal annealing process in ambient conditions. Tunable anisotropic emission was observed between wavelengths of 590 and 720 nm with a spectral resolution of 5 nm. This emission can be maintained for at least 11 days when proper passivation coupled with adequate storage is applied. Using hyperspectral imaging X-ray photoelectron spectroscopy (i-XPS), this tunable emission is found to be strongly dependent on the level of oxidation. We finally discuss the underlying mechanism responsible for the observed tunable emission and show that tunable emission is only observed in nanosheets with thicknesses of (70–125 nm) ± 10 nm with the maximum range achieved for nanosheets with thicknesses of 125 ± 10 nm. Our results shed some light on an emerging class of 2D oxides with potential in optoelectronic applications.

中文翻译：

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脉冲热退火层状黑磷的室温宽带可调光致发光

摘要 新探索的二维 (2D) 材料由于层状材料的带隙及其厚度可调，显示出良好的光学性能。一种广泛使用的实现可调光发射（或光致发光）的方法是通过厚度调制，但这只能覆盖特定波长。这种方法限制了在很宽的波长范围内具有高光谱分辨率的可调谐光学器件的开发。在这里，我们报告了在环境条件下通过脉冲热退火过程剥离的黑磷纳米片的宽带可调光发射。在 590 和 720 nm 的波长之间观察到可调谐的各向异性发射，光谱分辨率为 5 nm。如果采用适当的钝化和适当的储存，这种排放可以保持至少 11 天。使用高光谱成像 X 射线光电子能谱 (i-XPS)，发现这种可调发射强烈依赖于氧化水平。我们最后讨论了导致观察到的可调发射的潜在机制，并表明可调发射仅在厚度为 (70-125 nm) ± 10 nm 的纳米片中观察到，最大范围是厚度为 125 ± 10 nm 的纳米片。我们的研究结果揭示了一类具有光电应用潜力的新兴二维氧化物。我们最后讨论了导致观察到的可调发射的潜在机制，并表明可调发射仅在厚度为 (70-125 nm) ± 10 nm 的纳米片中观察到，最大范围是厚度为 125 ± 10 nm 的纳米片。我们的研究结果揭示了一类具有光电应用潜力的新兴二维氧化物。我们最后讨论了导致观察到的可调发射的潜在机制，并表明可调发射仅在厚度为 (70–125 nm) ± 10 nm 的纳米片中观察到，最大范围是厚度为 125 ± 10 nm 的纳米片。我们的研究结果揭示了一类具有光电应用潜力的新兴二维氧化物。