Study On The Photoelectric Performance Of Graphene-Based Organic Solar Cells

With the increasing pursuit of clean energy,it is urgent to seek for renewable clean energy which can replace fossil energy.As a kind of clean energy,dye-sensitized solar cells(DSSCs)have attracted the attention of many energy researchers because of their good compatibility with rigid and flexible semiconductors and easy matching of conduction band energy levels.In addition,as the nanoscale manufacturing technology is becoming more and more mature,nanomaterials have been gradually applied in various industries.Therefore,the purpose of this work is to explore the feasibility of the application of nanometer graphene materials in DSSCs.First of all,we explore the effect of graphene quantum dots(GQDs)to fill the photosensitive layer.The multibranched dye JH-1 as the photoactive layer material was used to analyze the non-negligible role of graphene quantum dots from the perspectives of optimized structure,electrochemical parameters,optical properties,nonlinear optical(NLO)switch,and external electric field.Secondly,we investigate the effects of a graphene layer between the photosensitive layer and semiconductor substrates on the electron transport performance of dye-sensitized solar cells from the perspective of intramolecular arrangement and interfaces.The benzothiadiazole sensitizer YKP-88 is used as the photosensitive layer,and the influence of the graphene layer on the short-circuit current density(Jsc)and open-circuit voltage(Voc)is also discussed by exploring the frontier molecular orbitals,intramolecular charge transfer,weak interaction,interfacial electron dynamic propagations and other microscopic parameters after the anchoring of the graphene layer.The results demonstrated that the graphene quantum dots not only improve the optical properties of solar cells but also control the electron transfer in the photosensitive layer molecules under the manipulation,of a specific external electric field.When the external electric field intensity is below 20×10-4 au,the excess electron orbital does not change.When the external electric field reaches 25×10-4 au,the excess electron orbital on the graphene quantum dots evolves.This discovery allows the electron transfer from the photosensitive layer,which should be controlled by the NLO switch.In addition,the graphene layer can accelerate the electron injection of dye molecules into the semiconductor substrate,which not only has a qualitative reduction in injection time,but also has a qualitative change in the increase of the injection amount,thus increase the Jsc and Voc of solar cells.Therefore,nanometer graphene materials can be used as a new way to improve the photoelectric performance of DSSCs.