Probing the Photophysics of Er- and Ce-Doped MoSe ₂ via Cathodoluminescence and Photoluminescence Excitation Spectroscopy

In this study, the cathodoluminescence (CL) and photoluminescence (PLE) excitation spectra are investigated thoroughly in hydrothermally synthesized erbium- and cerium-doped MoSe 2 in powder form in a specific concentration of dopants. Cathodoluminescence spectra show the 5d–4f transition of the Ce ion in Ce-doped MoSe 2, making this 2D host an efficient UV-luminescent material. Similarly, the exhibition of intra “F” and “I” electron transition of Er ion in Er-doped MoSe 2 confirms the visible and NIR luminescence ability of the material. All the CL results pay an excellent tribute to UV–visible spectroscopy and photoluminescence and simultaneously produce excitonic peaks of MoSe 2 and dopants without any excitation-dependent restrictions. Furthermore, the photoluminescence excitation spectra (PLE) reflect the complete UV absorption band of the Ce ion in Ce-doped MoSe 2 for all the corresponding emission peaks under UV and blue excitations. Again, PLE spectroscopy shows evidence of all visible and NIR absorption bands of the Er ion for up-conversion (UCL) and down-conversion photoluminescence (DC) in Er-doped MoSe 2, with corresponding emission peaks under NIR excitation. It also gives a direct reflection of the mechanistic processes involved in UCL and DC emission among the Er energy level. Finally, the PLE spectra show how the excitation band of MoSe 2 plays the role of displaying the characteristics and excitonic emission peaks of MoSe 2 along with the doping effect.