<human>:  What are recent developments in the field of solar energy?
<bot>: Recent developments in solar energy include the increased affordability of solar panel systems, advances in battery storage technology, and the development of more efficient solar panels. Other advances in solar energy include the emergence of thin-film solar cells, use of nanotechnology in solar cells, and the development of organic solar cells. Additionally, recent innovations in solar cells include the development of solar panels that are both flexible and transparent.