This fact sheet describes a next-generation thermionic solar energy conversion project awarded under the DOE's 2012 SunShot Concentrating Solar Power R&D award program. The team, led by Stanford University, seeks to demonstrate the feasibility of photon-enhanced, microfabricated thermionic energy converters as a high-efficiency topping cycle for CSP electricity generation. With the potential to double the electricity output efficiency of solar-thermal power stations, this topping cycle application can significantly reduce the cost of solar-thermal electricity below that of the lowest-cost, fossil-fuel generated electricity.