The stimulation and ultimately control of excitons and phonons in nanoscale electronic materials under real-world operating conditions are critically important to the realization of solutions that address our energy needs now and into the future. The Electronic Materials Program pursues the understanding and manipulation of excitons and phonons in nanoscale electronic materials under real-world operating conditions that are critically important to the realization of solutions addressing our energy needs now and into the future. The program advances the state-of-the-art knowledge of i) photoscience in low-dimensional materials at room temperature and ii) thermal science of engineered semiconductors. It elucidates the mechanisms underlying photoluminescence quantum yield, phonon transport, light-matter interactions, and other fundamental processes enabling to push the performance limits of materials relevant to energy applications. Through a combination of materials theory, advanced spectromicroscopies, and materials synthesis, it will perform fundamental studies on the role of defects and strain fields on carrier recombination, exciton dynamics, and phonon transport. The program develops materials in which structural as well as electronic phases are designed to achieve control of radiation and thermal transport beyond what is currently available.