Color-tunable luminescence, energy transfer behavior and I–V characteristics of Dy3+,Eu3+ co-doped La(PO4) phosphors for WLEDs and solar applications

Abstract

In the present investigation, different concentrations of Dy³⁺,Eu³⁺ doped and co-doped La(PO₄) phosphors were synthesized via the solid-state synthesis route. Furthermore, their structural, morphological, vibrational features, thermal stability, spectroscopic behavior, energy transfer mechanism, photometric results, I–V characteristics and spectral response in solar cells were investigated in detail. The XRD pattern of the synthesized phosphor confirmed the successful preparation of Dy³⁺,Eu³⁺ doped and co-doped La(PO₄) phosphors. Using their XRD data, Rietveld refinement was performed and structural behavior was studied. Dy³⁺ activated La(PO₄) phosphors exhibit blue (482 nm) and yellow (571 nm) emission under different UV and blue excitations (350 nm, 364 nm, 388 nm and 454 nm). Whereas, Eu³⁺ activated La(PO₄) phosphors show emission in the orange (593 nm) and red (618 nm) region. In this investigation, excitation spectra of Eu³⁺ and emission spectra of Dy³⁺ overlapped each other. On the basis of spectral overlapping, energy transfer behavior was investigated. The synthesized co-doped phosphors show blue and yellow emissions with some red emission. Further, the synthesized co-doped phosphors were coated on solar cells and their I–V characteristics were investigated. The I–V characteristics and spectral response of the solar cell suggested that our synthesized phosphors may be useful for enhancing solar cell efficiency. The color tunable features also suggested that synthesized phosphors have good potential for white LED applications.