The commercial solar cells are currently less efficient in converting solar radiation into electricity. During electric power convention, most of the absorbed energy is dissipated to the surroundings. In order to improve energy efficiency, many efforts have been made to investigate and develop hybrid photovoltaic and thermal collector systems. A photovoltaic–thermal (PV/T) system does both the generation of electric power and collection of thermal energy at the same time. Thus, the overall efficiency of the photovoltaic–thermal (PV/T) system can increase accordingly. In this work, we attempt to summarize various research works on technologies like flat–plate PV/T systems and concentrator type PV/T systems, using different kinds of working fluids under a variety of environmental conditions. The purpose of this review is to define the appropriate environmental conditions and applications for different kinds of PV/T systems. Besides, it is also presented that the applications and developments of the PV/T systems. In order to develop novel PV/T systems, more effort is needed in accurate modeling, exploration of novel materials, enhancement of PV/T system stability and the design of a supporting energy storage system .