Organic-inorganic Hybrid Perovskite Solar Cells

Organic / inorganic hybrid perovskite solar cell has become a research hotspot in the field of photovoltaic due to its high power conversion efficiency,low cost and simple preparation process.Since its inception in 2009,the perovskite solar cell has made great progress.However,some issues remained to be studied intensively because of the short development time.Firstly,the controllable preparation of perovskite is still a challenge and its growth kinetics need to be clarified;Secondly,the perovskite solar cell shows different transport behavior from the traditional device,Such as hysteresis effect,the effect of light pretreatment on the output performance of the device,etc.,the physical mechanism is unclear;Thirly,how to enhance the efficiency of flexible perovskite solar cell by improving the carrier extraction rate is need to be studied intensively.Foused on the above problems,this dissertation carries out the following research work:（1）By adjusting the concentration,immersion temperature and soaking time of CH₃NH₃I solution in two-step immersion method,the diffusion behavior,nucleation density and reaction rate of CH₃NH₃I in PbI₂ were effectively controlled,and the reaction kinetics mechanism was systematically analyzed.The results showed that when the immersion time of 10 min and the concentration of CH₃NH₃I solution was 10 mg / ml,the efficiency of 11% was achieved for the solar cell;（2）The CH₃NH₃PbI₃ thin films were prepared by two-step spin coating method.The influence of CH₃NH₃I concentration on the crystal properties,surface morphology and light absorption properties of the films was systematically analyzed.The results showed that when the concentration of CH₃NH₃I was 70 mg / ml,the surface of CH₃NH₃PbI₃ was dense and the phase purity was high,and the power conversion efficiency of the solar cell was 12.3%;（3）The influence of light pretreatment on the output performance of perovskite solar cell was studied systematically.It was found that the light pretreatment could improve the output performance of the device in the first 3 minutes,but the efficiency of the device was reduced when the light pretreatment time was extended to 7 min.The light induced properties of the perovskite solar cells were analyzed in view of ion movement.（4）One-dimensional CH₃NH₃PbI₃ nanowires were successfully grown on the flexible PET substrate by adding a small amount of DMF in the CH₃NH₃I solution by the modified two-step spin coating method.Interfaced with Zn O,the CH₃NH₃PbI₃ nanowires showed a faster electronic extraction rate compared with the conventional thin films,which would open up a new way to improve the efficiency of flexible perovskite solar cell.