Broadband photoluminescence of Bi₂O₃–GeO₂binary systems: glass, glass-ceramics and crystals

Abstract

Ultra-broadband emission covering 1000-1800 and 1800-3020 nm of Bi 2 O 3 -GeO 2 binary system materials, from glass to glass-ceramics to crystals, is presented in this paper. This is the first time, to our best knowledge, that broadband photoluminescence of BGO crystals (including Bi 4 Ge 3 O 12 and Bi 12 GeO 20 ) in the range of 1800-3020 nm has been realized. HRTEM, XPS and XANES have been used to investigate the effects of the valence states and the structure environment of bismuth on the emission properties of Bi 2 O 3 -GeO 2 binary system materials. Bi 2+ and Bi + are proposed as the emission centers of the photoluminescence peaks at 1060 and 1300 nm, respectively. The broadband emission from 1800 to 3020 nm originates from bismuth clusters. Bi 2 O 3 -GeO 2 binary system materials could be promising laser materials in the field of full-band optical fiber communication amplifiers, ultra-fast lasers and diode pumped solid state lasers, due to their broadband emission spectra and their feasibility of synthesis and drawing into fibers.

Origin of near-IR luminescence in Bi_2O_3–GeO_2 and Bi_2O_3–SiO_2 glasses: first-principle study

“…1(a)). The luminescence in the 1.8-3 µm range observed in annealed Bi 2 O 3 -GeO 2 glasses [14] and in Bi 4 Ge 3 O 12 and Bi 12 GeO 20 crystal [15] in the absence of the 1.2-1.3 µm luminescence may be caused by = Bi · · · Bi = center, an O vacancy between two Bi atoms ( Fig. 1(b)).…”

“…In binary Bi 2 O 3 -GeO 2 systems, however, distinctly different luminescence occurs. The luminescence in the 1.2-1.3 µm range excited at 0.5, 0.8 and 1.0 µm was observed in [12][13][14][15] and x ≈ 0.01 [16] [15]. Annealing glasses in oxidative atmosphere [12][13][14][15] or adding oxidant (CeO 2 ) in glass [19] led to a decrease in the luminescence intensity evidencing convincingly oxygen-deficient character of the luminescence centers.…”

“…The luminescence in the 1.2-1.3 µm range excited at 0.5, 0.8 and 1.0 µm was observed in [12][13][14][15] and x ≈ 0.01 [16] [15]. Annealing glasses in oxidative atmosphere [12][13][14][15] or adding oxidant (CeO 2 ) in glass [19] led to a decrease in the luminescence intensity evidencing convincingly oxygen-deficient character of the luminescence centers. In Bi 2 O 3 -Al 2 O 3 -GeO 2 glasses [20,21], in Bi 2 O 3 -GeO 2 glass prepared in alumina crucible [16] 2 and SiO 2 (namely, O vacancy and twofold coordinated Si or Ge atoms), but as well similar ODCs containing Bi atoms (BiODCs), namely, = Bi · · · Ge ≡, = Bi · · · Si ≡, = Bi · · · Bi = vacancies and twofold coordi-nated Bi atoms.…”

Does the low optical band gap of yellow Bi3YO6 guarantee the photocatalytical activity under visible light illumination?

“…It may be concluded that electroactivity recorded on the cyclic voltammetry curves is related to the changes of Bi species on the surface of the electrode. Thus, cathodic polarization of the electrode leads to the formation of the BBi suboxides^ [57,58] as the increase of the intensity of the peak related to the reduced form of Bi is observed.…”

Produção e caracterização de guias de onda dopados com terras-raras contendo nanopartículas semicondutoras.

“…Foram utilizados vidros ao invés de filmes, pois no caso dos vidros a concentração de bismuto é mais facilmente controlada (apenas pela proporção entre os óxidos de germânio e bismuto) do que nos filmes. , Neste caso, a emissão deve migrar para a região do infravermelho médio, por volta de 3000 nm [101]. Foram feitas medidas de luminescência em tais vidros e de fato a curva de emissão situada no infravermelho próximo se desloca nas amostras com alta concentração de bismuto.…”