The major problem that limits solar cells’ efficiency is their insensitivity to the whole solar spectrum which is the so-called spectral mismatch. Therefore, several mechanisms have been explored based on photoluminescence (PL) to convert the solar cell spectrum where the spectral response of the solar cell is low to regions where the spectral response of the solar cell is high. Downconversion, up-conversion (UC) and downshifting are some of the mechanisms that may be applied to improve the spectral response. Upconversion nanoparticles (UCNPs) have shown some promising possibilities to be considered in this respect, however, low UC efficiency of UCNPs is still the most severe limitation of their applications. This study reports on the PL and cathodoluminescence (CL) behaviour of different phosphors. The vastly studied lanthanide pairs in UC are Er³⁺, Ho³⁺ and Tm³⁺ with Yb³⁺ as a sensitizer. Whereas, very few UC studies have been carried out for Yb³⁺/Tb³⁺ and Yb³⁺/Eu³⁺ pairs. The reason behind these two categories of lanthanides is the way they transfer their energies. Er³⁺, Ho³⁺ and Tm³⁺ co-doped with Yb³⁺ can be excited by ground state absorption (GSA), excited-state absorption (ESA) and energy transfer up-conversion (ETU) mechanisms whereas the energy transfer from Yb³⁺ to Tb³⁺/Eu³⁺ is due to co-operative energy transfer (CET). Since, Tb³⁺ and Eu³⁺ do not have energy levels which can absorb the near infra-red (NIR) light directly, Yb³⁺ is the best choice in order to obtain the UC luminescence in Tb³⁺/ Eu³⁺ doped system. Yb³⁺ has a single electronic transition within the 4f subshell. The transition from the lower level through ground state absorption can be easily achieved by using NIR radiation, and resulting energy from two or more excited Yb³⁺ ions can be utilized in the excitation of a single Tb³⁺ or Eu³⁺ ion, for gaining improved UC emission. Doping different host materials with these lanthanide pairs were investigated and tested for possible increase in solar cell efficiency. Power tuneable visible UC and infrared emissions were detected upon excitation with a 980 nm diode laser.