Controllable ultra‐broadband visible and near‐infrared photoemissions in Bi‐doped germanium‐borate glasses

Abstract

The design of functional materials with tunable broadband luminescence performance is still of great interest in the fields of lighting, solar cells, tunable lasers, and optical amplifiers. Here, via a melt‐quenching method, a series of bismuth (Bi)‐doped germanium‐borate glasses with composition of 40GeO2–25B2O3–25Gd2O3–10La2O3–xBi2O3 have been prepared, in which multiple Bi active centers can be stabilized simultaneously. Dual‐modulating modes of visible (380‐750 nm) and near‐infrared (NIR) (1000‐1600 nm) broadband photoemissions were effectively controlled under flexible excitation scheme. Photoluminescence (PL) spectra at low temperature 10‐298 K were appropriately employed to interpret such an unusual wide visible emission band. To further illustrate the origin of NIR component, transmission electron microscopy (TEM) measurement was carried out. It is demonstrated experimentally that the visible emission mainly originates from the collective contribution of the 3P1/3P0false→1S0 transitions of Bi3+, while the broadband NIR luminescence should be related to the formation of low valent Bi+ and (or) Bi0 centers. This work may help to enhance the knowledge of the complex luminescence mechanism for the Bi species and it also enables such transparent glass materials to be a promising candidate for the multifunctional tunable light source.

Abnormal Bi3+-Activated NIR Emission in Highly Symmetric XAl12O19 (X = Ba, Sr, Ca) by Selective Sites Occupation

“…Bi 3+ ions can emit various light from blue to red in inorganic compounds. , Moreover, the photoluminescence excitation (PLE) band of Bi 3+ usually locates in the n-UV region, which can effectively avoid the spectral reabsorption phenomenon, thus increasing the luminous efficiency . It was reported that some Bi 3+ -functionalized aluminoborate and germanium-borate glasses can emit broad-band NIR emission (800–1600 nm), − but the low transmittance of glasses limits the large-scale applications. Besides, the NIR emission of Bi 3+ -activated phosphors is seldom reported, except for BaBPO 5 :Bi 3+ phosphors .…”

BiF3 Incorporation in Na/Ba Mixed Network Modifier Fluoride–Phosphate Glasses: Structural Studies by Solid-State NMR and Raman Spectroscopies

“…Glasses containing bismuth have thus far been proposed in applications such as broadband high gain optical amplifiers, tunable lasers, and fibers; , however, Bi 3+ ions can also function as sensitizers to increase the efficiency of energy transfer to rare earth ions for specific photovoltaic applications . Numerous bismuth-containing systems have been prepared on germanate, silicate, phosphate, borate, and oxyfluoride glass bases and characterized with respect to their physical properties.…”

Tunable broadband photoluminescence from bismuth‐doped calcium aluminum germanate glasses prepared in oxidizing atmosphere

“…Thus, Bi 2+ may exist as nonluminescent centers in the glasses discussed in this study. In addition, the lifetime of Bi 3+ in crystals is normally in the range of 10 −5 –10 −8 s. In our previous report, we observed a lifetime of ∼1 μs in Bi‐doped aluminate glasses, which is in the same order of magnitude as the luminescence lifetime of bismuth in germanate glasses and phosphors, especially for aluminate phosphors 70–72 . Thus, we tend to attribute this emission to the 3 P 1 → 1 S 0 transition in Bi 3+ 73 .…”

“…In addition, the lifetime of Bi 3+ in crystals is normally in the range of 10 −5 -10 −8 s. In our previous report, we observed a lifetime of ∼1 μs in Bidoped aluminate glasses, which is in the same order of magnitude as the luminescence lifetime of bismuth in germanate glasses and phosphors, especially for aluminate phosphors. [70][71][72] Thus, we tend to attribute this emission to the 3 P 1 → 1 S 0 transition in Bi 3+ . 73 With the introduction of higher amounts of GeO 2 , the emission intensity of this band continuously decreases, which is accompanied by a blue-shift from about 490 to 410 nm, as seen in Figure 6C.…”