Photovoltaic-thermal (PV-T) solar air/water collectors have received increasing attention in recent years. Efficiency is the most important parameter usually considered in PV-T technologies. The present paper expressed energy efficiency and thermal-electrical exergy of PV-T collectors, and compared the studies of researchers on the performance of these systems. The figures are provided to give an overview of how PV-T performance is improved. Changes in heat transfer fluid play a major role in electrical and thermal efficiency. A brief overview of the most promising fluids used in PV-T is reported in this article. Nowadays, improving PV- T performance by optimizing the adsorbent plate and cooling fluid and using nanofluid has been considered by researchers. The application of these schemes in implementation, especially in agriculture, can help significantly in increasing the efficiency of solar radiation. Therefore, future work should be aimed at increasing efficiency and reducing costs to increase their competitiveness and use as a renewable and environmentally friendly energy device
