Concentrating solar power (CSP) is a mainstream of solar energy utilization, and thermionic emission is a potential way to convert concentrated solar radiation into power with a theoretical efficiency of 50–70%, surpassing both Shockley-Queisser limit and photo-thermal limit. This literature attempts to provide a comprehensive understanding of and an insight into solar thermionic energy conversion. The fundamentals of electron emission from electrodes and electron transport in vacuum gap are presented, as well as the state of the art of solar thermionic energy conversion technologies, including heat-induced thermionics and photon-enhanced thermionics. The former is driven by thermal energy, whereas the latter takes advantage of both quantum photon energy and thermal energy. Burgeoning research indicates that photon-enhanced thermionic conversion is a promising technology for concentrating solar power due to the high efficiency and simple operating mode. Now, it is important to develop novel materials and coating technologies to facilitate electron emission and reduce space charge effect in interelectrode vacuum. Structural design of thermionic converters and top–bottom configuration of solar-electricity systems are suggested for practical applications.

聚光太阳能（CSP）是太阳能利用的主流，热电子发射是将聚光太阳辐射转换为电能的潜在方法，其理论效率为50-70％，超过了肖克利-奎塞尔极限和光热极限。该文献试图提供对太阳能热电子能量转换的全面理解和见解。介绍了从电极发射电子和在真空间隙中进行电子传输的基本原理，以及太阳能热电子能量转换技术的最新技术，包括热感应热电子和光子增强热电子。前者由热能驱动，而后者则利用量子光子能和热能。新兴研究表明，由于效率高和操作模式简单，光子增强型热电子转换是一种有前途的聚光太阳能技术。现在，重要的是开发新颖的材料和涂层技术，以促进电子发射并降低电极间真空中的空间电荷效应。对于实际应用，建议采用热电子转换器的结构设计和太阳能系统的上下结构。