Research On Fabrication And Stability Of FeS₂Nanocrystals/Polymer Hybrid Solar Cell

Nanocrystals/polymer solar cells have the advantages of low-cost, simple process and flexible manufacturing. However, presently the solar cells based on nanocrystals have issues of low photovoltaic convertion efficiency (PCE) and poor stability. FeS2nanocrystal has special optical absorption in visible and near-infrared region, which can overcome the defects that organic polymer absorption confined to visible region and improve active layer absorption spectrum to be in coincide with solar irradiation spectrum, thus enhance the performance of solar cell greatly.In this thesis, high quality FeS2nanocrystals were prepared via solvothermal method. FeS2nanocrystals/polymer solar cells were fabricated in inverted structure. Optimization of fabrication process was carried out to enhance PCE of solar cells. Moreover, the discussion on the concentration of FeS2nanocrystals adding to polymer was conducted with contrastive analysis, and the stability of FeS2nanocrystal polymer solar cell was investigated. The achieved results are listed as following:(1) Based on the facile solvothermal method, pure FeS2nanocrystals were synthesized with sphere shape around40nm in diameter. It has strong absorption at750nm, which is in high coincidence with the solar spectrum.(2) The optimization of the fabrication of TiO2layer and active layer showed that TiO2nanocrystal was better to transport electron; the active layers prepared at spin speed of1500rpm with the thickness of80nm, which could shorten the distance of electron transmission, effectively reduce the possibility of electron composite. The preferable temperature for annealing treatment was150℃, in order to remove organic ligands and reduce gain boundary defects in solar cells.(3) The solar cells incorporated FeS2nanocrystals with concentration of1.25mg/ml showed PCE of3.0%. The device also had high stability; remaining83.3%of its original PCE after15weeks, and its performance kept almost the same at20-80℃. With irradiation intensity ranging from500W/m2to2000W/m2, PCE fluctuation magnitudes were not more than20.8%, showing more stable than quantum-dot-sensitized solar cells.