Defect Sate Control In Organic Hybrid Perovskite Film And Used For Solar Cell

Organometal trihalide perovskites have been demonstrated as one of the most excellent light harvesters for high-efficiency photovoltaic applications. Perovskites have believed to be one of the substitutions of silicon industry due to its abundant element resource, simple fabrication process, and high power conversion efficiency ?PCE?. Though the PCE has boomed to over 20% by now, there are still great challenges to obtain non-toxic and stable solar cells. Thus, here we start to consider the problems of widely existed defect in perovskite films and to find a simple method to obtain high quality perovskite in order to fabricate an high performanc perovskite solar cell. Besides, device structure optimization is also a very important portion to be concerned. In this thesis, we firstly investigate the effection to perovskite and its devices by ambient. Then introduce a double layer method to solve the low fill factor ?FF? problem of perovskite device with CuI as a single hole-transport layer. Finally we mainly illustrate two different additives incorporation, CuI and alkyl halide such as iodomethane ?CH₃I?, into perovskite precursor solution. We demonstrate significantly improvement of CH₃NH₃PbIxCl3-x perovskite film grain crystallization and orientation, along with enhancement of film optical properties, achieving photoluminescence ?PL? lifetimes up to 4 ?s which is the record ever reported. We propose the huge improvement is due to the reduction of trap states in CH₃NH₃PbIxCl3-x perovskite along with the increase of exciton and its diffusion length in the film. Both additives enhance perovskite solar cell performance. CuI mainly affects the V_oc which obtains 1 V and PCE improve to 14.28% while CH₃I improves all device parameters of V_oc, JSC and FF, achieving a highest PCE of 16.18%.