Research Of Perovskite Solar Cells Based On Compact Layer

In these years,perovskite solar cells（PSCs）have developed rapidly,and the highest photoelectric conversion efficiency（PCE）has been certified to 22.1%,which shows great prospects in the field of photovoltaic.In PSCs,a compact layer is usually required to prevent the direct contact between FTO and perovskite active layer.However,on the one hand,the low electron mobility of c-Ti02 always lead to the charge accumulation on the interfaces,which would result in hysteresis in the PSCs;On the other hand,the c-TiO₂ typically need high-temperature processed,which may limit the roll-to-roll manufacturing of low-cost PSCs on flexible substrates.In this thesis,efforts were mainly devoted to investigate the compact layer materials based on the printable PSCs,for further improving the hysteresis and simplifying the fabrication process in the PSCs.Achievements had been made as follows:（1）Hole-conductor-free printable PSCs based on SnO₂ compact layer（c-SnO₂）were designed and researched.C-SnO₂,which prepared by spray pyrolysis using a solution of dibutyltin bisacetylacetonate in ethanol,was demonstrated to be an excellent alternative compact layer for efficient hole-conductor-free printable MPSCs.The best device with such a c-SnO₂ has achieved a PCE of 13.77%.Furthermore,J-V curves from forward and reverse sweeps at different sweep rates for the MPSCs based on c-SnO₂ and c-TiO₂ were measured,and their hysteresis index values were calculated.It is interesting to find that the PSC based on c-SnO₂ showed a lower hysteresis index than that of the device with c-Ti02.PL spectroscopy and EIS data proved that highly efficient charge extraction is important to suppress hysteresis effects.（2）Compact-layer-free,hole-conductor-free printable PSCs were designed and researched.The best device presents a PCE of over 13%,which is comparable to that of the device with a TiO₂ compact layer（c-TiO₂）.PL spectroscopy and EIS data indicate that the elimination of c-TiO₂ is a feasible scheme in the structure of fully printable triple layer PSC.The different wettability of the perovskite precursor solution on the surface of FTO and TiO₂ possess a significant effect on realizing efficient PSCs.The innovation points of the work include the following two aspects:on the one hand,c-Sn02 was demonstrated that it could reduce charge accumulation at the interface;on the other hand,a compact-layer-free PSC was prepared and the "cavity theory" was put forward.