Currently, silicon nanoparticles (SiNPs) are of great interest due to their potential applications in various fields such like optoelectronics, microelectronics, photonics, photovoltaics, chemical, and biologic sensors. SiNPs Become the most important and well-known semiconductor because Si-based devices have dominated microelectronics for many decades. Indeed, the production of smart SiNPs materials to enhance absorption and light scattering is currently the most convenient approach.<p> </p>Recently, plasmonic fractal-like structures have been determined to enhance photovoltaic device performances; indeed, through an efficient coupling of the incident light at different frequency bands into both the surface plasmon modes and the cavity modes, a broadband absorption enhancement can be accomplished.<p> </p>Silicon nanoparticles exhibit fluorescence deriving from Si quantum dot structures which are produced during chemical etching, and it can be synthesized with unique optical reflectivity spectra. These unique characteristics allow porous silicon to exhibit a signal that is affected in a expected way when exposed to environmental changes, presenting possibilities for the development of advanced functional systems that incorporate sensors for therapeutic functions or diagnostic.<p> </p>In order to prevent rapid degradation after administration and to increase their blood half life, biocompatible polymers coating was performed on silicon nanoparticles. Different type of biocompatible polymers (chitosan, polylactic acid, PMMA, or dextran,) can be used.<p> </p>However, several methods have been developed for the synthesis of silicon nanoparticles such as chemical etching, sol-gel technique, laser ablation, sputtering process; hot-wire synthesis, ball milling process, and microemulsion.<p> </p>The main objective of this research is to develop a new technique for coating or encapsulation of Nanoparticles to modify their surface properties by using different polymers. Furthermore, polymers are non-toxic, non-flammable, relatively inexpensive and recyclable.
Engineering a low-cost graphene- based opto-electronic device is a challenging task to accomplish via a single-step fabrication process. Recently scientists have started focusing on the development and use of a laser-based method for efficient reduction of graphene oxide (GO) films at low-temperature. Our proposed technique utilizes a laser beam for non thermal reduction of solution processed GO layers onto film substrates. Compared to other reduction techniques, it is a single-step, facile, time consuming, non-contact operation, environment-friendly, patternable, low cost, and can be performed at room temperature in ambient atmosphere without affecting the integrity of either the physical properties or the lattice of graphene. Laser scribed reduced graphene (LSRG) is shown to be successfully produced and selectively patterned from the direct laser irradiation of graphite oxide films under ambient conditions. In addition, by varying the laser's intensity, power, and irradiation treatments, the electrical properties of LSRG can be accurately attune over five orders of magnitude of conductivity. Feature has proven difficulty with other methods. This credible, scalable approach is mask-free, does not require certain expensive chemical reduction agents, and can be performed at ambient conditions starting from aqueous graphene oxide flakes. The non thermal nature of this method combined with its scalability and simplicity, makes it very attractive for the manufacturing of future generation large-volume graphene-based opto/electronics.
Localized Surface Plasmon Resonance (LSPR) that occur in plasmonic nanoparticles due to interaction with electromagnetic waves at wavelengths larger than the nanoparticles themselves has been exploited in many application like solar cells, cancer treatment and spectroscopy due to the enhanced scattering and absorption cross sections that LSPR provides. Being able to control the resonance peaks of scattering in real time using light can be a valuable tool for sensing-related applications as well especially if it happens in the near and Mid-IR spectrum where most of the biological molecules can be sensed as such spectrum contains strong characteristic vibrational transitions of many important molecules . In this work presented here, we used silicon nanoparticles and increased the concentration of free excess carriers in the nanoparticles by light generation until the free carrier concentration was large enough to cause LSPR similar to what we get with nanoparticles made of Noble metals. The LSPR generated by Si nanoparticles with high concentration of free carriers caused the resonance peak to happen in near and mid IR. Depending on the level of carrier concentration which can be changed dynamically in real time, we can control the scattering resonance peak characteristics and position as shown in our work. Successful fabrication of the Silicon nanosphere is demonstrated as well.