Structural and luminescence properties of Dy3+ doped oxyfluoro-borophosphate glasses for lasing materials and white LEDs

Concentration dependent spectroscopic behavior of Sm3+ doped leadfluoro-borophosphate glasses for laser and LED applications

“…formation of M-O-P bonds [9] and further PbO posses dual bonding nature with the network formers such as Pb−O bond is ionic when PbO 6 structural units were seen in the glass network and Pb−O bond is covalent when PbO 4 units were formed [1]. It leads to enhance the mechanical strength, thermal stability, chemical durability and reduces the glass transition temperature of the boro-phosphate glasses and further enhance the radiative transition rates of the RE ions [1].…”

“…In glasses, the conduction band is influenced by the glass forming anions and the cations play an indirect but significant role. The absorption coefficient α(ω) driven from the Mott and Davis theory have been used to establish the relationship between the band gap and absorption coefficient α(ω) and the same is expressed using the below given equation [9,12] (αћω) r = B(ћω−E g )…”

“…such as direct allowed, direct forbidden, indirect allowed and indirect forbidden transitions respectively [9]. The optical band gap values were obtained by extrapolating the linear region of the plot of (αћω) r versus E (i.e.…”

“…Urbach's energy gives the exponential behavior of the absorption coefficient near the band edge (λ e ) and is calculated using the below given Urbach's empirical formula [9] α(ћω) = Cexp(ћω/∆E) (2) where, α is the absorption coefficient, C is the constant and ‫ܧ∆‬ is the Urbach's energy.…”

“…A C C E P T E D (9) where λ p is the emission transition peak wavelength, n is the refractive index of the glass and ∆λ eff is the effective line width of the transition which is calculated using the following equation [12] …”