Based on the author's own work and results obtained by renowned cosmologists, this short book provides a concise introduction to the relatively new research field of cosmological thermodynamics. Starting with a brief overview of basic cosmology and thermodynamics, the text gives an interesting account of the application of horizon thermodynamics to the homogeneous and isotropic Friedmann-Lemaitre-Robertson-Walker (FLRW) model, the inhomogeneous (Lemaitre-Tolman-Bondi) LTB model, and the gravitationally induced adiabatic particle creation scenario which is considered to be a viable alternative to the concordance Lambda-CDM model of the Universe. Both seasoned and new researchers in this field will appreciate the lucid presentation and the rich bibliography.

Present century is the era of nanotechnology with its exciting and versatile field of applications towards mankind. In unison, over the past decades, nanophosphors have been extensively investigated due to its enormous application potential for various high-performance novel displays devices, in non-linear optics and also in fast optical switching. Consistently, discovery of many rare earth materials played a prominent role to develop highly efficient luminescence materials. Surprisingly enough, intentional doping of these impurities (rare earth ions) in quantum confined (nanomaterial) regime explicitly enhances the emission efficiency of the phosphor materials. Thrust is still going on to find better nanophosphors, having high brightness and colour purity with lower excitation energy. Charge compensation by Li+ co-doping in the rare earth doped phosphors is one of the attractive and convenient tools to improve their brightness with high colour purity. So our sole interest is to enhance the brightness of nanophosphors; we contributed a little in this regard by co-doping Li+ in MgAl2O4: Eu3+ nanophosphor.