International Research Journal of Engineering and Technology (IRJET) e-ISSN: 2395-0056 Volume: 07 Issue: 08 | Aug 2020 www.irjet.net p-ISSN: 2395-0072 © 2020, IRJET | Impact Factor value: 7.529 | ISO 9001:2008 Certified Journal | Page 544 Light-based Technologies and Materials Innovation: A Review Mohit Kumar Gupta 1 , Shailesh Kumar Singh 2 , 1 Student M.Sc., Monad University 2 Associate Professor K.K University Bihar ---------------------------------------------------------------------***---------------------------------------------------------------------- Abstract - Presents a good opportunity to reflect on the current and future impact of light based technologies and the role of physics in guiding that impact. For example, when we think of light and energy there are two approaches that come to mind: the here and now technologies (Si-based photovoltaics, solar thermal) and the "around the corner", high-risk, high-reward directions awaiting further development. A common link between both approaches is materials innovation and introducing new physics of light- matter interactions. Key Words: materials innovation, light based technologies, Si-based photovoltaics, solar thermal. 1. INTRODUCTION Discovery of new materials: Predictive materials physics:In many ways, the light-based technologies in use today are limited by the performance of materials. This motivates the discovery of new materials, exploring materials physics of existing materials and exploiting new device concepts. Advanced materials share a common attribute: They are complex. Therefore achieving required performance depends on exploiting the many degrees of freedom of materials development including (but not limited to) multiple chemical components, nanoscale architectures, and tailored electronic structures. This introduces enormous complexity in the discovery process, complexity that must be understood and managed. A theory bias here would argue that we do not have the time or resources to explore all the options experimentally. However, our current computational methods confer upon us predictive power to accelerate discovery and innovation in materials. During the past decade, computer simulations based on a quantum-mechanical description of the interactions between electrons and atomic nuclei have had an increasingly important impact on materials science, not only in fundamental understanding but also with a strong emphasis toward materials design for future technologies. While the current theory tools are not perfect, they do provide sufficient information for theory- directed design of new materials and new materials physics. In addition to the computational design of materials for solar cells, artificial photosynthesis, and photochemical pathways to fuels, the need to computationally predict and optimize the light-matter interactions in materials is general and relevant to several light-based technologies including: • Optical circuits • Displays • Solid-state lighting • New light sources A further link between established and to-be-developed technologies is that any new approaches must to some extent be integrable with dominant pervasive technologies and processes. This raises issues such as CMOS compatability and considerations of growth mechanisms, and on a more fundamental level the importance of both interface and volume effects in any new materials. This is particularly pertinent for nanostructured materials due to their increased surface-to-volume ratio. Hence, an adequate description of the physics occurring at interfaces of any new optoelectronic material must be taken into account in materials design and development from the start. In many cases, a single theory method or approach may not be enough. A strategy of multiscale simulations must be used to translate the results of atomistic calculations to real-world scales. Some aspects of this thesis (especially the chapters on ab initio plasmonics) illustrate the need and use of multiscale theory. 2. MATERIALS PHYSICS FOR ENERGY Solar technologies, whether photovoltaic or solar-fuel based, are ultimately limited by the efficiency of the light absorber. One of the primary goals of this thesis has been to investigate new light capture and conversion strategies through materials discovery. Artificial photosynthesis imposes unique demands on the light absorbers, relative to conventional photovoltaics. In artificial photosynthetic devices, either a single material, or two absorbers arranged in a tandem cell format (and currentmatched spectrally), must at minimum provide the thermodynamically required voltage of 1.23 V to split water, and must provide comparable voltages to reduce CO2 to methanol or other fuel. However, very few Earth-abundant materials have been identified that have band-gaps in the 1.5-2.2 eV range and satisfy the requirements for photoabsorbers in a solar fuels device. This presents a unique opportunity for exploring new materials physics especially in context of wide bandgap semiconductors. Optoelectronic properties and relaxation dynamics of these wide bandgap semiconductors would find applications beyond artificial photosynthesis in solid state lighting and photovoltaics.