LSPR Regulation Of Core-shell Gold Nanoparticles And Its Application In Polymer Solar Cells

Due to the depletion of traditional fossil energy,the continuous deterioration of the environment and people's increasing awareness of environmental protection,the demand for alternative energy is increasing day by day.More and more attention has been paid to polymer heterojunction organic solar cells because of their low cost and environmental protection.In polymer solar cells,the absorption of photons,the generation and separation of excitons,and the transport and collection of carriers all occur in the active layer of the heterojunction or in the interface between the active layer and the electrode.In order to improve the performance of polymer solar cells,it is very important to control and optimize the morphology of the heterojunction.In addition,how to effectively enhance light absorption through interface design and regulation without increasing the thickness of the active layer has become the key to the preparation of polymer solar cells.In this paper,PTB7:PC₇₁BM was used to prepare a series of photovoltaic devices by introducing dopamine-coated core-shell gold nanoparticles?Au@PDA?.The modification of electron transport layer?ETL?by Au@PDA and its influence on device performance were discussed.Firstly,gold nanoparticles?Au NPs?with a particle size of about 30 nm were prepared by Frens reduction method,and the core-shell structure material Au@PDA was obtained by dopamine?DA?self-polymerization on the Au NPs surface.PDA can effectively modify the surface of Au NPs to improve its stability and regulate spectral response.Adjust the thickness of the PDA shell by changing the aggregation time of DA.Then,by changing the proportion of donor material?PTB7?and acceptor material(PC₇₁BM),adjusting the thickness of active layer,regulating the annealing condition,changing the preparation method of Zn O electron transport layer,etc.,the suitable preparation process of PTB7:PC₇₁BM polymer solar cell was explored:the Zn O ETL was prepared by sol-gel method,the ratio of donor and acceptor was 1:1.5,the active layer was spun at 1200 RPM and anneal was conducted at 120? for 10 min.Under this condition,the short current density of the device reaches 11.14 m A/cm²,and the power conversion efficiency reaches 4.64%.Finally,Au@PDA was used to modify the surface of ETL.Due to the local surface plasmon resonance effect,the introduction of Au@PDA can increase the absorption of light by the active layer without increasing the thickness of the active layer.In addition,PDA can effectively combine with Zn O ETL to reduce its surface defects and improve the contact between the interface layer and the active layer.When the DA polymerization time was 1h,the short current density of the modified polymer solar cell reached 13.98 m A/cm²,and the power conversion efficiency reached 6.03%,which was 130% of the device without the Au@PDA.