Photonic sintering of nanoparticles is a relatively new process for sintering of nanoparticles, deposited on a substrate, into functional solid structures. The working principle of this process is the incidence of large-area broad-spectrum light onto deposited nanoparticles, which results in heat generation in the nanoparticles and their subsequent densification. Key advantages of photonic sintering include rapid, scalable and ambient condition operation. For these reasons there is significant interest in using this process as a manufacturing solution for nanoparticle sintering in emerging applications like RFID tags, flexible electronics, solar cells, and sensors. Despite preliminary demonstrations of photonic sintering, there is little knowledge on the underlying process physics, which results in limited physics-based control of the process. The goals of this work are to (1) expand the state of knowledge on the physics of photonicsintering; and (2) develop a system that can leverage the advantages of photonic sintering for low-cost additive manufacturing using nanoparticle building blocks.Four key topics in photonic sintering are investigated. First, the effects of nanoparticle size on densification and the temperature (of deposited nanomaterial and substrate) are experimentally characterized. Both the temperature and nanoparticle densification are found to be highly dependent on the nanoparticle sizes used. Secondly, a multiphysical model of photonic sintering is developed to link particle size, optically-induced heat generation, resulting temperature rise and consequent interparticle necking. In addition to reflecting experimentally observed trends, the developed model also provides an improved understanding of the underlying physics behind photonic sintering. Thirdly, densification and temperature evolution in photonic sintering of non-metallic nanoparticles is characterized.Lastly, photonic sintering and inkjet deposition are combined into one system to demonstrate the potential of using photonic sintering for a low-cost, multi-material, desktop additive manufacturing system. With further hardware and software development and greater understanding of the physics behind photonic sintering, the developed additive manufacturing system can be further refined. Further development and commercialization of the system developed here has the potential to increase accessibility of low-cost, multi-material additive manufacturing (metals, semi-conductors and ceramics) similar to the currently increased accessibility of polymer 3D printing.