The rapid adoption of electric vehicles (EVs) has intensified the need for sustainable charging infrastructure. Conventional grid-based charging systems remain constrained by fossil-fuel dependence, geographic unavailability, and grid overloading risks. Solar photovoltaic (PV)-based EV charging has emerged as a compelling alternative, offering zero-emission operation, energy independence, and long-term cost viability. This paper synthesizes findings from seven peer-reviewed studies spanning standalone PV designs, simulation-based performance analyses, smart grid-integrated frameworks, and IoT-enabled architectures. Key parameters including energy yield, battery state of charge, converter configurations, and economic payback are analyzed and compared. Recurring challenges such as high initial cost, weather dependency, and infrastructure gaps are critically examined, and future directions including AI-based energy management, Vehicle-to-Grid (V2G) technology, and policy-driven deployment are outlined. The findings confirm that solar EV charging is technically proven, economically sound over its operational lifetime, and essential for achieving low-carbon transportation.