Study On The Application Of Graphene Quantum Dots In Silicon Based Hybrid Solar Cells

Generally speaking,the utilization of solar energy includes photoelectric conversion,photothermal transformation,and photochemical utilization,photoelectric conversion is the most important way of current solar energy utilization.Solar cell device is the basis of photoelectric conversion,its conversion efficiency,cost,stability and applicable environment determine the potential and prospect of the whole photovoltaic industry.Traditional silicon solar cell technology is complex.Both photoelectric conversion efficiency and production cost run into the bottlenecks,and its production process is accompanied by serious environmental pollution.Silicon based hybrid solar cells can combine organic materials which have the advantages of low cost,easy modification and good conductivity and the silicon based materials which the surface is easy to prepare micro-nano structure.However,a large reduction of silicon material in the silicon based hybrid solar cells makes the light absorption capacity of the battery weaker.The weaker conductivity of the organic layer affects the efficiency of the carrier delivery,resulting in its low photoelectric conversion efficiency.In the device,we design and prepare effective light management structure,improve its optical absorption performance,improve the conductivity of organic layer,and introduce new functions,which are the two main directions to improve the efficiency of hybrid solar cells.In recent years,the introduction of graphene quantum dots into organic layers and the preparation of micro nano structures on silicon surface have shown good prospects for the development of high efficiency solar cell devices.In this paper,in view of the three aspects of controllable preparation of uniform graphene quantum dots,optimization of fabrication technology of silicon surface micro nano structure,and optimization of silicon based hybrid solar cell device performance,research work of the system has been carried out,and the main contents are as follows:(1)The homogeneous and homogeneous graphene quantum dots were prepared by high temperature strong acid solution stripping method,and the controllable preparation process was explored,and its influence on the device parameters was characterized.By adjusting the time of the high temperature reaction and the subsequent optimization and purification process,the quantum dots of graphene with uniform size of 5 nanometers are prepared.It provides the basis for the efficiency of the subsequent silicon based organic-inorganic hybrid solar cells.(2)The preparation of micro nano structure on silicon surface and the preparation of ultrathin monocrystalline silicon wafer have been studied.The micro nano structure of silicon surface with different morphologies was prepared by metal assisted etching,and ultra-thin silicon with 20 microns thickness was prepared by alkaline solution etching.According to the performance of solar cells witch own different silicon micro and nano structure,the optimal silicon micro nano structure size was determined.A flat silicon based hybrid solar cell device with mechanical flexibility is prepared based on ultra-thin monocrystalline silicon wafer.(3)The graphene quantum dots are applied to three kinds of surface structure organic-inorganic hybrid solar cells.The graphene quantum dots are also applied to the flexible ultrathin silicon based hybrid solar cells.We fabricated three kinds of Si based hybrid cells,namely,flat silicon/PEDOT:PSS/GQDs,surface Pyramid/PEDOT:PSS/GQDs and silicon nanowire/PEDOT:PSS/GQDs,and analyzed their performances.Among all kinds of battery components,the performance of the silicon nanowire/PEDOT:PSS/GQDs battery device has reached 11.91%.The ultrathin flexible graphene quantum dot hybrid solar cells were prepared,and a flexible battery device with an efficiency of 7.03%was prepared.