**2. Experimental details**

on community their novel optical and electronic properties. To synthesize novel thin film materials such as molybdates [1, 2], tungstates [3], vanadates [4], and fluorides [5], copious prominent techniques are extensively adopted, for example chemical bath deposition (CBD), successive immersion layer adsorption reaction (SILAR), polymerization, electrodeposition, sputtering, metal-organic chemical vapour deposition (MO-CVD), molecular beam epitaxy (MBE), atomic layer deposition (ALD), pulsed laser deposition (PLD). In the midst of all, PLD is a multitalented method to prepare multiconstituent thin film materials in which raster examining of high-energy pulsed laser ablates the target material and produces the plasma plume [6, 7]. In recent times, the PLD technique has created a widespread usage with an exceptionally astonishing result in materials preparation and fabrication of a device in the optoelectronics field. Albeit the fabrication of optical quality of the thin films and waveguides using PLD technique with various technical hitches and burning issues, till date, these issues have undeniably been lucratively conquered, and quite a few good-quality thin films were grown by

34 Applications of Laser Ablation - Thin Film Deposition, Nanomaterial Synthesis and Surface Modification

In contrast to conventional incandescent and fluorescent lamps, white light emitting diode (w-LEDs) is seemed to be an optimistic solid-state light source with a good-quality energy conversion luminescence device [8]. By coalesce into the GaN blue LED chip with yellow emitting phosphor YAG:Ce3+ which yield a white light emission using the conventional technique [9–11]. Nevertheless, the deficient of red emission cog ends with low colour rendering index (CRI) and luminous efficacy of radiation (LER) which restricts their pertinence towards a few ambits [9, 12]. To conquer this hindrance, red or orange-red emitting ion such as Pr3+, Sm3+, Cr3+ and Mn2+ is co-doped with YAG:Ce3+ [10]. The other one is combining YAG:Ce3+ with red or orange-red phosphors such as nitrides (M2SiN8:Eu2+), sulphides (CaS:Eu2+), oxynitrides (MSi2O2N2:Eu2+) (where M = Ca, Sr) [10]. Furthermore, the enhancement of intense emission in the host material can be engendered by co-doping of alkali metalchloride results in strong emission, which may possibly be an opportune and a generally suitable approach to acquire the phosphors with sufficient intensity and excellent efficiency are a great essential deal for prospective solid-state lighting devices [2]. Therefore, it is necessary to discover a suitable phosphor material with a sufficient chemical permanence with enhanced efficiency. Rare earth-doped phosphor materials are paying attention towards the research problems based on its applications in all the prospects of science and technology. Molybdates and tungstates with metallic elements form an essential class of phosphor materials. They belong to the scheelite family having a space group I41/a. In both molybdate and tungstate family, the alkaline earth-based rare-earth-activated double molybdates are very much highly significant efficient materials on the basis of its unique structural, optical properties have come across profound applications in technological aspects. Alkaline rareearth-activated tungstates having a general formula ARE (MoO4)2 (RE = Y, La; A = Ba, Ca, Sr) are considered as better luminescent hosts investigated significantly for various purposes such as photocatalysts [11], displays [8] and acquire substantial hydrolytic and thermal permanence. Furthermore, the electroluminescent devices in the form of thin films from these micro/ nano-architectures are to be built for the white light emitting diode applications. Among the

PLD.

**1.1. Recent research scenario**

By employing the PLD technique, for the first time, the nano-thin phosphor films of Ca0.5R1-*x*(MoO4)2:*x*Ln3+ (*x* = 0.16 M) (R3+ = Y, La), (Ln3+ = Eu, Tb, Dy) with co-doping of alkali metal chlorides (0.02 M of LiCl, KCl, NaCl) were effectively coated on the quartz substrates by maintaining the substrate temperature of 600°C under oxygen atmospheric pressure (∼300 mTorr). **Figure 1a**–**i** shows the images of different experimental procedures engaged for the growth of thin films.
