Executive Summary : | Photon upconversion (UC) is a nonlinear optical phenomenon where sequential absorption of two or more low energy photons leads to high energy emission. UC nanoparticles have numerous applications, including lighting, materials, probes, and bioimaging. However, challenges remain, such as low UC efficiency due to weak and narrowband NIR absorption and the need to create new particles with high absorbance at different wavelengths. Significant advances have been made in synthesizing and multifunctionalizing UCNPs with controlled size, shape, and dissolution properties. However, most works focus on understanding the processes involved in biological systems. Non-specific binding is common with hybrid UCNPs, and dual emission allows for ratiometric measurements at two excitation or emission wavelengths, which eliminates artefacts due to concentration variation, photobleaching, or instrument-related parameters. Integrating different functionalities could provide solutions in molecular detection and bioimaging. The study of hybrid materials consisting of lanthanide-doped NPs and dual fluorescent organic dyes or LRET from UCNPs to such dye has not been done to the best of the investigator's knowledge. Emissions from UCNPs in addition to dual emissions of such dye would offer a broader range of emission, higher tunability of photon emissions, and better scope for ratiometric measurement. This would enhance the benefit of multiplexing, allowing multiple probes to be monitored simultaneously in a single assay. |