**2.1. Preparation of ceramic target, cleaning of substrates and growth of Ca0.5R1-***x***(MoO4)2:***x***Ln3+ nano-thin phosphor films**

To prepare a strong and extremely impenetrable ceramic (molybdate and tungstate) target for laser ablation, the starting precursors such as Na2CO3, La2O3, Y2O3, MoO3 and Ln2O3 (Ln = Eu, Tb, Dy) were taken in stoichiometric ratios along with 0.02 M of alkali chlorides (LiCl, KCl and NaCl), followed by using the agate mortar pestle the powders were grounded for 2 h. The doping concentrations of Ln3+ were optimized in our previous work [15] and kept at constant (0.16 M) for all the Ln3+ ions. Without using any binders, the homogeneously mixed powders were pressed and pelletized in the form of disk (pellet) at a pressure of 6 tons. By eliminating the unstable contaminants, shun pores, crack, and endorse densification, to promote the diffusion in atomic level all through the preparation of target [16]. Furthermore, the asprepared pellet was annealed at 900°C for 3 h to achieve a very strong, stable and thick pellet having a diameter of about 2.5 cm, and thickness of about 0.4 cm is attained. Then, the annealed target is used for laser ablation.

**Figure 1.** Photograph of different experimental methods demonstrating (a) homogeneously pelletized ceramic target, (b) high-temperature annealed target, (c) cleaning of substrates, (d) target loading, (e) loading of substrates, (f) impurities removal in UHV chamber (glow discharge), (g) laser ablation, (h) target after ablation, (i) thin films after deposition.

The procedure for predeposition cleaning of substrates and growth of nano-thin phosphor films were already discussed in detail on our previous work [2].
