Efficient near-infrared emission at 1070 nm in (Eu3+/Nd3+) ions pair activated NAFBT glasses by CET process for improving the silicon solar cell efficiency

Present work reveals the luminescent downconversion (LDC) process in a series of new sodium-aluminumfluoro borotellurite (NAFBT) glasses by co-doping Nd3+ concentrations (0.1, 0.5, 1.5, and 2.0 mol%) with a constant (2.0 mol%) Eu3+ content. The X-ray diffractogram and IR spectral studies have shown the amorphous like structure and functional groups of the fabricated NAFBT glasses. The fabricated glasses’ physical properties like density and molar volume, and their absorption in the 300–780 nm (UV-Visible) and 800–2300 nm (NIR) ranges were studied. The LDC effect via co-operative type energy transfer (CET) in NAFBT:(Eu3+/Nd3+) glasses was tested with the stimulation at 463 nm of Eu3+, showing a prominent 614 nm (visible) photon of Eu3+ and 907, 1070, and 1339 nm photons (NIR) of Nd3+ ions. The variation in percentage (%) of the integrated intensity at 1070 nm (Nd3+) and 614 nm (Eu3+) was studied as a function of Nd3+ concentration at a fixed Eu3+ content. The multipolar interactions between Nd3+ and Eu3+ ions in NAFBT glasses were studied by Reisfeld and Dexter energy transfer (ET) process. The decline of PL decay from 1.91 to 0.38 ms was represented by dipole-quadrupole interaction in NAFBT glasses. Asymmetric ratio and photometric parameters such as correlated color temperatures (∼1020 K), and (x, y) color coordinates nearly (0.65, 0.34) of red emission were also evaluated for NAFBT glasses. The intense NIR (1070 nm) emission matches well with the silicon solar spectrum and an increase of conversion efficiency (ηQE) from 125% to 199% demonstrate the potential application of NAFBT glass materials in crystalline silicon (c-Si) solar cells.