Downshifting and up-conversion luminescent properties of triple molybdate NaCaLa(MoO_4)_3:Tb~(3+)/Yb~(3+) phosphor for solar cell application

摘要

The insufficient utilization of incident solar radiation in UV and IR region by existing single-junction photovoltaic devices restrict their efficiency. The triple molybdate NaCaLa(MoO_4)_3:Tb~(3+)/Yb~(3+) phosphor was synthesized by solid state method in order to harness the unutilized part of solar spectrum. The structural and optical studies such as X-Ray diffraction (XRD), Photoluminescence (PL), Up-conversion (UC) and UV-Vis diffuse reflectance characterizations were carried out to examine the prepared sample. The structural refinement of XRD powder data of prepared phosphor was also performed with space group I4_1a(88). The sample was characterized by dual excitation i.e. UV and IR radiation that shows green emission corresponds to ~5D_4-~7F_5 transition of Tb~(3+) ions. The obtained results indicate that synthesized material can be used as spectral converter to convert unutilized incident solar photons into the energies that are more effectively absorbed by the solar cell, hence efficiency can be improved.