Solar panels are made using chemistry. There are huge opportunities in eliminating toxic chemicals and fugitive emission from the manufacturing process, while reducing costs. The wafer processing needed to make the solar cells, the adhesives used to seal the solar panels, and the methods of electrically connecting the cells together are all major opportunities to improve solar panels. Then there are totally different and new chemistry being developed for new type of solar cells and panels such as thin film.
Renewable energy requires solar, wind, and wastes converted to oil and gas. Waste conversion to oil and gas, and hydrocarbons for reserve generators, long haul and chemical feed stocks is some intense chemical processing. Fischer–Tropsch, gassification, pyrolysis, fractional distillation and condensation , and many new processes as well. I consider waste to hydrocarbons to be the underdeveloped piece of the whole renewable energy future. Research investment in it is growing as people realize the potential, but there are very few operating plants in the world.
Now you need to research and see which ones interest you the most, then what job opportunists there are.
Have fun, do great work!