Upconversion luminescence of Gd2O3:Er3+ and Gd2O3:Er3+/silica nanophosphors fabricated by EDTA combustion method

Preparation and Characterization of Gd2O3: Er3+ Nanosphere Particles Combinated with Chitosan Gd2O3: Er3+@CS

“…The PL spectrum observed the characteristic emission of Er 3+ ions, in which the green and strong green emissions of the Gd 2 O 3 :Er 3+ NSPs are assigned to the transitions of 2 H 11/2 → 4 I 15/2 (548 nm and 538 nm), 4 S 3/2 → 4 I 15/2 (562 nm and 553 nm), and weak red transition 4 F 9/2 → 4 I 15/2 , respectively. 20,21 We observed a higher green emission efficiency than that of red emission.…”

“…The PL spectra of Gd 2 O 3 :Er 3+ @CS samples consist of a weak intense at 660 nm, a robust green peak at 562 nm, and some weaker emissions at 553 nm, 548 nm, and 537 nm, which correspond to the characteristic transitions of 4f → 4i, 4s → 4i, and 2 h → 4i energy levels of Er 3+ in Gd 2 O 3 crystal, namely 4 F 9/2 → 4 I 15/2 , 4 S 3/2 → 4 I 15/2 , 2 H 11/2 → 4 I 15/2 , respectively. [20][21][22] The most substantial green emission band in Fig. 4b arises from the 4 S 3/2 → 4 I 15/2 transition.…”

“…Note that the UCL emission of Gd 2 O 3 :Er 3+ NSP samples with and without chitosan-coated obtained enhancement of the red emission compared with other NSP samples prepared by the combustion procedure. 20 This reason suggests that the relationship between the location and population of the 4 F 9/2 transition was exited. The strong UCL emission of the Gd 2 O 3 :Er 3+ @CS sample might be used for applications in biomedicine, photodynamic therapy, and drug delivery.…”

“…This absorption process is assigned to two-photon excitation, which agrees well with previous reports. [20][21][22] We also clearly investigate and obtain the energy diagram for Gd 2 O 3 :Er 3+ @CS structure in up-and down-conversion emissions, as shown in Fig. 8.…”

Upconversion Luminescence Properties of Gd₂O₃: Er³⁺ Nanospheres and Gd₂O₃: Er³⁺@Silica Nanocomposites

“…11) We have also previously studied the UCL processes of Gd 2 O 3 : Er 3+ monoclinic crystal and Gd 2 O 3 : Er 3+ @Silica nano phosphors fabricated by EDTA combustion synthesis method. 12) In the last years, there are studies of the UCL spectra of Er 3+ in gadolinium oxide. 13,14) Some laboratories reported Gd 2 O 3 nanoparticles codoped Yb and Er.…”