Research And Application Of Organic Solar Cell Graphene Interface Material

In recent years,more and more attention has been paid to the issue of energy.So organic solar cells with high efficiency and low cost have become one of the research hot spots.The power conversio n efficiency of single-junct ion organic solar cells in the literature has exceeded 16%.However,the energy conversio n efficiency and st a-bilit y of organic solar cells st ill need to be fu rther improved before they can be gen-erally commercialized.At present,organic solar cells st ill have the following pro b-lems:1.In the process of device preparat ion,most of the toxic organic solvents are used,which pollutes the environment and increase s the cost;2.There is a potent ial barrier between the electrode material and the act ive layer because of the energy level mismatching,so the interface layer needs to be introduced.However,the commo nly used anode interface layer,PEDOT:PSS,affects the stabilit y of the device due to its acidit y and hygroscopicit y.Due to its special structure,graphene has many excellent propert ies,such as good light transmittance,high conduct ivit y,high carrier mobilit y at room temperature,etc.,which determines tha t it can be used as an anode interface layer in organic solar cells.In response to the above problems,this paper proposes the following sol ut ions:1.In this paper,modified graphene was used as the anode interface layer in the trans device of organic so lar cells.In order to reduce the use of organic solvents,we designed and prepared sulfonic acid-based graft-modified water/alcohol-dispersible graphene,in two size of the graphite powder as raw material,intercalat ing the grap h-ite powder with an intercalat ing agent,and ultrasonic stripping.Finally we obtained two sizes of graphene.Then the obtained graphene was analyzed by infrared spe c-troscopy（FT-IR）,thermogravimetric analysis（TGA）,laser Raman spectroscopy（Raman）,X-ray diffract ion（XRD）,atomic force microscope（AFM）and scanning electron microscope（SEM）.Comparing the qualit y of two kinds of size of graphene,the results show that large size graphene 1 is bet ter,with size of micron level,a thickness of 1.5nm and a few layers.It has better dispersio n in water/alcohol and can be processed in solut ion in subsequent applications.2.In order to meet the condu ct ivit y of the interface material and the energy level matching between the act ive layer and the electrode material,the graphene material was further modified with quaternary ammo nium salt,and tested by cyclic volta m-metry（CV）,and using the CV curve to calculate the modification of graphene mat e-rials HOMO energy level.The results show that the quaternary ammo nium salt can improve the HOMO energy levels of graphene materials,and improve electrical con-duct ivity,which is the theoret ical basis for the preparation of high efficiency and low cost of organic solar cells.3.Modified graphene is used in organic solar device.The anode interfa ce using modified graphene/MoO₃ double-layer structure,compared with the single structure of MoO₃ device,quaternary ammonium salt modification of graphene make short circuit current increased by 5%,fill factor is increased by 30%,and the energy con-version efficiency increased by 36%,indicating that the modified graphene can be used as the anode interface layer of organic solar cells to improve the device performance.