| 英文摘要
| This thesis mainly focuses on two different but related parts, namely defect passivation of crystal-controlled MAPbI3 with polymer ionic liquid for efficient perovskite solar cells (Chapter 3) and low temperature oxygen plasma sintered SnO2 as electron transport layer for planar perovskite solar cells (Chapter 4). The overview of these two applications will be displayed in introduction (Chapter 1). Moreover, the experimental procedures (Chapter 2) includes the chemical reagent, material characterization and the principle of device analysis.
In Chapter 3, we successfully synthesized a new polymer ionic liquid (PIL), poly[vinylidene fluoride-co-hexafluoro propyleneco-vinylideneaminooxomethyl-1-butylimidazolium choloride] denoted as PFICl. Which was grafted of 1-butylimidazolium chloride onto poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP), The PFICl was incorporated into the CH3NH3PbI3 precursor to control the perovskite crystal growth in a one-step spin coating process. The long chain polymer act as the scaffold which assist perovskite crystal growth. Meanwhile the polymer ionic liquid formed hydrogen bond with the nitrogen atoms in methylammonium iodide (MAI), as witnessed by the slow down process of crystallization and NMR peak shift. The result shows that a more compact perovskite film with larger grain size has been prepared. Meanwhile, we found the PFICl passivated the perovskite layer surface, thereby making the charge transfer process more effective. With this method, the solar cell efficiency is enhanced from 14.5 to 17.0%.
In Chapter 4, a low temperature (about 70 °C) oxygen plasma treatment was applied to in fabrication of SnO2 films. This method is a simple photochemical treatment which is simple to operate and can be easily applied to the organic components. In addition, PSCs with oxygen plasma-sintered SnO2 films as ETL were successfully fabricated. The device exhibited excellent photovoltaic performance as high as 16.7%, which is even higher than the value (14.6%) reported for a counterpart device with solution-processed and high temperature annealed SnO2 films as ETL. This ltemperature solution-processed and oxygen plasma-sintered SnO2 films are suitable for the low-cost, large yield solution process on a flexible substrate for optoelectronic devices. |
