Herein, we report a new series of Ba_1+xSr_1−xGa₄O₈:Bi³⁺ (x = 0–0.7) phosphors that exhibit extremely broadband emission, covering almost the entire visible region and extending to the deep-red region, when excited by ultraviolet light. BaSrGa₄O₈:Bi³⁺ exhibits two emission bands located at 470 and 570 nm originating from different emission centers. With the gradual substitution of Ba for Sr, both of the emission bands show a red-shift, from 470 to 510 nm and from 570 to 630 nm, respectively. The corresponding full width at half maximum (FWHM) increases from 192 to 283 nm, which is attributed to a superposition of multiple emission centers via crystal field regulation. As a result, the emission can be tuned from cyan to orange across the warm white light region in Ba_1+xSr_1−xGa₄O₈:Bi³⁺ (x = 0–0.7) systems. Simultaneously, this series of phosphors presents good thermal stability (97% intensity at 150 °C for the Ba_1.5Sr_0.5Ga₄O₈:Bi³⁺ sample) and the thermal quenching will decrease with the formation of a solid solution due to the increasing rigidity of the lattice structure. Interestingly, the two emission bands in the representative Ba_1+xSr_1−xGa₄O₈:Bi³⁺ (x = 0–0.7) sample exhibit different thermal responses to increasing temperature, thus an optical thermometer with color discrimination and good sensitivity is designed. The maximum relative sensitivity (S_r) is 1.295% K⁻¹ in the temperature range of 7–400 K. The corresponding emission color can be tuned from blue-cyan to orange, including white light. This work presents a rational design strategy for controllable ultra-broadband emission tuning across the white light region and to further explore potential optical sensor applications.

中文翻译：

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超宽带蓝绿色到橙色发射Ba1 + xSr1-xGa4O8：Bi3 +荧光粉：发光控制和光学温度感测

在此，我们报告了一系列新的Ba _{1+ x} Sr _{1− x} Ga ₄ O ₈：Bi ³⁺（x = 0–0.7）荧光粉，这些荧光粉具有极高的宽带发射能力，几乎覆盖了整个可见光区域，并延伸至深部。红色区域，当被紫外线激发时。BaSrGa ₄ O ₈：Bi ³⁺展示了来自不同发射中心的两个发射带，分别位于470和570 nm。随着Ba逐渐取代Sr，两个发射带都显示出红移，分别从470 nm到510 nm和570 nm到630 nm。相应的半峰全宽（FWHM）从192 nm增加到283 nm，这归因于通过晶场调节将多个发射中心叠加在一起。结果，可以在Ba _{1+ x} Sr _{1- x} Ga ₄ O ₈：Bi ³⁺（x= 0–0.7）系统。同时，这一系列的荧光粉具有良好的热稳定性（对于Ba _1.5 Sr _0.5 Ga ₄ O ₈：Bi ³⁺样品，在150°C时97％的强度），并且由于形成固溶体，热猝灭将减少。晶格结构的刚性增加。有趣的是，代表Ba _{1+ x} Sr _{1− x} Ga ₄ O ₈：Bi ³⁺（x= 0–0.7）样品对升高的温度表现出不同的热响应，因此设计了具有颜色识别和良好灵敏度的光学温度计。在7–400 K的温度范围内，最大相对灵敏度（S _r）为1.295％K ^-1。可以将相应的发射颜色从蓝青色调整为橙色，包括白光。这项工作提出了一种合理的设计策略，用于在白光区域内进行可控的超宽带发射调谐，并进一步探索潜在的光学传感器应用。