Abstract We present the structural and luminescent properties of Ho3+/Yb3+ co-doped Gd0.5Na0.5MoO4 nano-phosphor synthesized through the facile co-precipitation method at different calcination temperatures. The X-ray diffraction (XRD) patterns of the samples show the pure tetragonal phase formation. The upconversion (UC) spectra recorded on excitation with 980 nm laser show the intense emission bands at 545 nm (green) and 659 nm (red) in which red emission is more intense than green emission. The intense red is suitable for bio-imaging. Under 452 nm excitation, the intense green downconversion (DC) emission is observed. It is observed that with increasing the calcination temperature, the UC/DC emission intensity increases. One of the interesting features explored is the observation of intrinsic optical bistability (IOB). This material may be applicable in various fields such as biological cell imaging, phototherapy, optical switching, display devices, solar cells, etc.

中文翻译：

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Ho3+/Yb3+ 共掺杂钼酸钠钆纳米荧光粉的强烈红色和绿色发射：煅烧温度和本征光学双稳态的影响

摘要 我们介绍了通过简便的共沉淀法在不同煅烧温度下合成的 Ho3+/Yb3+ 共掺杂 Gd0.5Na0.5MoO4 纳米荧光粉的结构和发光特性。样品的 X 射线衍射 (XRD) 图案显示纯四方相的形成。用 980 nm 激光激发时记录的上转换 (UC) 光谱显示了 545 nm（绿色）和 659 nm（红色）的强发射带，其中红色发射比绿色发射更强烈。强烈的红色适合生物成像。在 452 nm 激发下，观察到强烈的绿色下转换 (DC) 发射。观察到随着煅烧温度的增加，UC/DC发射强度增加。探索的有趣特征之一是对内在光学双稳态 (IOB) 的观察。