Investigations towards more performing and more stable solution-processed hybrid perovskite solar cells

In this Ph.D. thesis,I have been focused to investigate optimizations and strategies concerning the electron transportlayer (ETL),the hybrid perovskite active layer, and their interfaces in functional perovskite solar cells. On the investigatior of ETLs, I have performed two works: One is on the comparison of a simplified ETL-free planar perovskite solar cells,architecture to that with a planar TiO2 ETL (described in Chapter 2); Another work is on the comparison of perovskite,solat cells with well-oriented one-dimension TiO2 nanocolumn (NA) ETL to those with a planar TiO2 ETL (Chapter 3).On,the investigations of the perovskite active layer, mixed-cation and mixed-halide perovskite was applied into three,relevant works: (1) I optinized and maximized the grain size of the perovskite active layer (Chapter 2); (2) I studied nano-,structured hybrid perovskite fims and their light-harvesting enhancement (Chapter 6): (3) I investigated the thermal,properties of mixed-cation perovskite thin films to understand their improved thermal stability compared to,methylammonium lead iodide (MAPbi3) perovskite (Chapter 4). In addition, I studied passivation methods to alleviate the interfacial charge recombination and to improve the stability of perovskite solar cells (chapter 5).