Absorption Properties of Er³⁺/Nd³⁺ Co-Doped Magnesium Phosphate Glasses

Abstract

Magnesium phosphate glasses co-doped with Er3+/Nd3+ concentration were prepared using melt quenching technique and thermal annealing process was proposed to control any defects found in the glass samples. The physical and optical properties of the samples were investigated. The amorphous nature of the samples were confirmed using X-ray diffraction pattern. It shows that all samples are in amorphous state. The optical band gaps and Urbach energies were obtained from the optical absorption spectra. The studyshows that the optical band gap energy,Eopt isincreasingas the Nd2O3 content increased. Meanwhile, Urbach energies, ΔE decreased due to increase of Nd2O3 content. The results obtained from this study shows that the optical band gap, Eopt and the Urbach energy, ΔE are intherange of 3.95 –3.98 eV and 0.367 –0.437 eV respectively.

Photophysical Characterization of Er3+ doped and Er3+/Nd3+ co-doped Gd(OH)3 Nanocrystals: the Impact of Hexamethylenetetramine utilization for Morphology Engineering

“…Upconversion Luminescence Result Upconversion (UC) luminescence for all synthesized samples were obtained via 980 nm laser excitation source at room temperature. The synthesized Gd(OH)3:Er0x (x = 0.01, 0.02, 0.03 mol ratios) nanocrystals without HMTA show grouped emission bands around 500 -575 nm (560 nm), 645 -700 nm (660 nm), 750 -780 nm (758 nm), and 780 -950 nm (875 nm) (Figure 12a) corresponding to the 4 S3/2 → 4 I15/2, 4 F9/2 → 4 I15/2, 2 H11/2 → 4 I15/2, and 4 S3/2 → 4 I13/2 transitions, respectively of Er 3+ ion [20,78,[78][79][80][81]. This work is reporting the emissions at 758 nm and 875 nm in Er 3+doped into Gd(OH)3 host for the first time.…”

“…This work is reporting the emissions at 758 nm and 875 nm in Er 3+doped into Gd(OH)3 host for the first time. The emissions from Er 3+ are known to be strongly host dependent [80] and this why the 4 S3/2 → 4 I13/2 transition is seldomly observed in some host. Moreover, the 4 I13/2 state been slightly higher than the 4 I15/2 ground state makes electrons at this state ( 4 I13/2) relatively unstable than the electrons at the ground state in some host.…”

“…Moreover, the 4 I13/2 state been slightly higher than the 4 I15/2 ground state makes electrons at this state ( 4 I13/2) relatively unstable than the electrons at the ground state in some host. However, in certain special host matrixes, some electrons at this 4 I13/2 level may be stable [80]. These special host matrixes could be those with low phonon energies ≤ 500 cm -1 .…”

“…All ions at the 4 F7/2 populated energy level relax via fast multiphonon de-activation to lower lying 2 H11/2 and 4 S3/2 levels from where some of the ions fall back radiatively to the ground state ( 4 I15/2) releasing photons at 560 nm. This process is known to compete with the thermalization processes since the relative population of these levels is said to depend on temperature in accordance with Boltzmann distribution [80].…”

“…Since the ESA involves a single ion, it is the prevalent mechanism in nanocrystals with low dopant concentration [49], giving the green luminescence from the relaxation from the 2 H11/2 or 4 S3/2 level to the ground state. The red emission may be caused by energy transfer process (ET2) involving the following pair states; ( 4 I13/2, 4 I11/2) → ( 4 I15/2, 4 F9/2) (17) Similarly, the emissions at NIR region (758 nm and 875 nm) are said to originate from 2 H11/2 and 4 S3/2 levels, respectively and terminated at 4 I13/2 level [80]. The pair 2 H11/2 and 4 S3/2 are among the three thermally coupled levels in Er 3+ used for temperature sensing (luminescence thermometry).…”