It　is　well　known　the　efficiency　of　photovoltaic　(PV)　modules　decreases　with　an　increase　in　operating　temperature.　In　this　paper,　we　have　investigated　this　phenomenon　through　classification　of　the　flat　plate　photovoltaic/thermal　(PV/T)　collector　into　four　configurations　(air-type,　water-type,　nanofuid-type　and　bi-fluid-type),　according　to　the　media　used　for　operation.　Benefits　of　using　the　different　operation　media　were　assessed　and　an　optimum　for　high　overall　efficiency　of　the　PV/T　collector　was　achieved.　Considering　different　variation　trends　in　electrical　and　thermal　efficiency　of　the　PV/T　collector,　the　effects　of　operation　media,　structural　designs　and　climatic　conditions　on　performances　of　flat　plate　PV/T　collectors　were　discussed　in　consideration　of　relevant　literature　reports.　Results　demonstrated　that　the　overall　efficiency　of　a　water-type　PV/T　collector　was　greater　than　an　air-type　PV/T　collector,　benefitting　from　the　higher　specific　heat　capacity　of　water　yet　with　a　complex　structure.　The　nanofluid-type　PV/T　collector　presented　a　higher　overall　efficiency　than　the　others,　due　to　the　high　thermal　conductivity　of　dispersing　nanoparticles　in　a　base　fluid　and　the　colloidal　stability　of　the　nanofluid.　Furthermore,　the　glass　cover　(with　or　without),　absorber　structure　and　relative　location　between　the　absorber　and　the　fluid　influenced　the　overall　performance　of　the　PV/T　collector.　In　addition,　the　primary　climatic　conditions　to　influence　performance　were　solar　radiation　and　environmental　temperature,　with　a　dependence　on　the　geographical　installation　region.　Future　studies　were　considered　through　progression　of　advanced　PV/T　technologies,　when　the　PV/T　collector　could　be　integrated　with　residential　and　public　buildings.