Photoluminescence and optical transition investigations of europium doped bismuth borate glasses for laser and LEDs applications

The current work present the fabrication and characterization of lithium based bismuth borate glasses doped with different europium contents. The grown samples were evaluated for its structural, physical, optical and luminescence investigations. The structural confirmation were conducted by XRD and FTIR spectra. The Absorption spectrum observed in UV-Vis-NIR region and demonstrate two sharp peaks at 2092 and 2200 nm. The bandgap and Judd-Ofelt parameters Ω2, Ω4, Ω6 were computed from absorption spectrum of LiBBiEu2.0 glass. Under 395-nm excitation five emission bands were discovered in the emission spectra. From photoluminescence emission spectra the radiative properties like branching ratio (83), stimulated emission cross section (590.595 × 10−22 cm2), and radiative transition probability (4087.90 s−1), were determined for 5D0→ 7F2 transition. The high optical gain 1.193 × 10−20 cm2 s of LiBBiEu2.0 glass make it possible to be used as best lasing material. From the 5D0 emission level of decay curve the experimental lifetime were calculated which decreased with rise in Eu3+ contents. The increased in orange-red (R/O) ratio with increase in Eu3+ contents confirm asymmetric environment around Eu3+ ions in the host glasses. Based on these results the developed glasses can be used as promising material in red LEDs and red laser in optical devices.