Research On Cholesteric Phase Liquid Crystal/fluorescent Materials Doping Impact On The Performance Of Organic Photovoltaic Devices

With the rapid expansion of the world's population,environment pollution and energy consumption are also growing.In order to satisfy the sustainable development and environmental constraints,renewable energy which is able to replace the traditional fossil fuel energy has been concerned by many national institutions because of its clean pollution-free,recreating and sustainable.Because solar energy possesses many advantages which is low cost,easy to obtain,clean pollution-free and never dried up,it has become one of the most important new energy in this century.Photovoltaic devices are able to convert solar energy into electricity directly,and therefore it can help people to solve the problem of environmental pollution and ease the energy crisis.As the first generation of solar cells,silicon-based solar cells occupy an important position in the photovoltaic market.However,its high production costs and complicated manufacture technology limit its further development.Organic solar cells have been widely concerned because of its advantages such as low-cost,simple fabrication techniques,etc.The research content of the thesis includes two parts.Firstly,the device performance of different cholesteric liquid crystal-doped organic solar cells is studied.It is found that the device which is doped cholesteric glycol oleate liquid crystal shows the best energy conversion efficiency of 3.09%.Benefiting for the self-assembly property of liquid crystal materials,the active layer molecules are well-organized to result in reducing of molecular cluster in the active layer and the defects of the thin film and form an efficient carrier-transform channel.Then,by comparing the effect of the doping ratio of cholesteric glycol oleate liquid crystal,it reveals that when the doping ratio is 0.3%,the device gives the best photoelectric property of the conversion efficiency improved from 2.49%?non-doping?to 3.09%.Secondly,the interface modification on fluorescent material addition in the electronic buffer layer Bphen of perovskite solar cell is investigated.In order to optimize the morphology and quality of film,the hybrid material Bphen: Ir?MDQ?₂?acac?is introduced as interface modification layer.The resultsshow that when the fluorescent material ratio is 10%,the device efficiency is improved from 10.77%to 15.87% compared to without doping.The reason is that the modified buffer layer can fill the holes on the surface of the perovskite film,reduce the film surface roughness,promote the carrier transport,and then improve the fill factor and efficiency.