Executive Summary : | Fluorescent organic compounds are often used to reveal fingerprints, although they are ineffective in detecting fingerprints on non-porous or reflective surfaces such as glass, compact disc, metallic surfaces etc. Inorganic phosphors were used to tackle the challenges of collecting fingerprints from non-porous/reflective surfaces because they are featured with variable colour emission, afterglow, high chemical stability, and nano-size. Over the past decade, many rare-earth-doped inorganic phosphors have been investigated due to their F→F sharp emission under near-UV excitation. These inorganic phosphors with rare earth elements are now used in fingerprint detection on porous and non-porous surfaces. More research in the field of development of inorganic nano phosphor has increased due to its potential utility in forensic science for detecting hidden fingerprints on all kinds of surfaces. Since we are lacking with rare-earths in our country, the dependency has increased on other countries like China, Australia, etc., which increased the price of such materials. Under self-reliant India, we have proposed rare-earth-free metal vanadate phosphors and their mechanism to improve luminescence of metal vanadate without using rare-earth. Metal vanadates A3(VO4)2 (A = Ca, Sr, Ba, Zn) phosphors are better than many oxide-based host materials with excellent luminescence capabilities. In compared to other oxide materials, these materials have good chemical and physical characteristics. Metal vanadate is a self-activated very good luminescent phosphor that gives better green-yellowish luminescence. Its luminescence property can further be improved via two ways; first by doping of alkali metal like Li+, Na+, K+, transition metal like Zn2+, Mn2+, and Bi3+ . The other way of increasing its luminescence properties is making this in nano-scale. The main objective of our project is to develop cost-effective, rare earth free, environment-friendly, and easy to handle materials for latent fingerprinting. Out of many synthesis processes of preparation of metal vanadate, we may use the auto-combustion method which is very easy and cost-effective. The excitation wavelengths of these phosphors is lying in near UV and visible range and the emission wavelength is in visible range so the utility of near-UV light to visible may be uses for these proposed phosphors. |