Tunable luminescence from Bi<sup>3+</sup> sensitized La<sub>2</sub>Zr<sub>2</sub>O<sub>7</sub>:Eu<sup>3+</sup> red nanophosphors for display applications
B.V. Naveen Kumar, Kankanala Venkata Rao, Esub Basha Shaik, Y. Nirmal Rajeev, Kokkirapati Ramachandra Rao, Sandhya Cole
Abstract
Abstract Bismuth ion (Bi 3+ ) sensitized, europium ion (Eu 3+ ) activated La 2 Zr 2 O 7 nanophosphors are prepared successfully by simple wet chemical method. Strong blue emission of singly doped La 2 Zr 2 O 7 with Bi 3+ was observed at 310 nm excitation, its wide emission spectrum has a peak maximum at 465 nm ascribed to electronic transition 3 P 1 → 1 S 0 of Bi 3+ . The recorded photoluminescence spectra of y at% Eu 3+ codoped La 2 Zr 2 O 7 , when excited at 285 nm, the emission spectrum exhibits maximum peaks at wavelength values 615 nm, 646 nm and 665 nm which are ascribed to 5 D 0 → 7 F 2 , 5 D 0 → 7 F 3 and 5 D 0 → 7 F 4 transitions of Eu 3+ respectively. The chromaticity coordinates for the optimized sample were found to be (0.519, 0.329). Sensitizing with Bi 3+ can affect the luminescence properties of La 2 Zr 2 O 7 :Eu 3+ phosphors. With reference to the change in Eu 3+ concentration from Y = 1, 2, 3, 4 and 5%, color tunable luminescence from blue to orange, red of La 2 Zr 2 O 7 :Bi 3+ ,Eu 3+ phosphors are observed. The lifetime decay values, energy level description and CIE chromatic color coordinates for Bi 3+ , Eu 3+ in La 2 Zr 2 O 7 :Bi 3+ ,Eu 3+ codoped sample was discussed. The spectral overlap between sensitizer, activator ions confirms the efficient energy transfer from Bi 3+ to Eu 3+ in La 2 Zr 2 O 7 :Bi 3+ ,Eu 3+ codoped sample and is via a dipole‐quadruple mechanism.