Preparation Of Triangular Silver Nanoplates And Their Applications In SERS And Polymer Solar Cells

Under the irradiation of incident light,noble metal nanomaterials will undergo intense charge accumulation and oscillation effects.The generated surface plasmon or local surface plasmon will form surface localization and near-field enhancement effects,which can be applied in many fields.Electron oscillation is sensitive to the change of physical parameters such as material size and shape.The excellent optical regulatable properties of triangular silver nanoplates due to their morphological and dimensional changes have attracted much attention and have been widely used in surface enhanced Raman scattering(SERS).By adding triangular silver nanoplates into polymer solar cells,local field enhancement induced by surface plasmon resonance(LSPR)can be utilized to capture solar energy efficiently into the active layer of polymer solar cells,thus effectively improving the light absorption and photoelectric conversion efficiency of the cells.In this paper,we focus on the application of triangular silver nanoplates in polymer solar cells and SERS.The main contents are divided into the following three parts:1.Preparation of triangular silver nanoplates.Seed growth method and ligand-assisted reduction method were used to prepare triangular silver nanoplates,and the influence of different experimental conditions on the size of silver nanoplates was explored.The results showed that the optimal mole ratio of reactants in ligand-assisted reduction was:AgNO3:TSC:H2O2:NaBH4=35:225:64:250.The triangular silver nanoplates obtained under this condition have side length of about 45 nm,thickness of 4.5 nm,good triangular state and complete tips.The optimal mole ratio of reactants for the synthesis of triangular silver nanoplates by seed growth method was:AgNO3:TSC:NaBH4=5:72:6 in seed solution and AgNO3:TSC:PVP:C6H8O6=30:450:102:125 in growth solution;under these conditions,the formed triangular silver nanoplates were in good shape and proved to be stable after repeated experiments.Triangular silver nanoplates prepared by seed growth method has better microscopic morphology,yield and stability than those prepared by the ligand-assisted reduction method,and the wavelength of LSPR can be easily regulated in the range of 500-900 nm.2.The application of triangular silver nanoplates in SERS.It was found that the triangular silver nanoplates system prepared by ligand-assisted reduction method had a high baseline,which would mask the characteristics of Raman signal;however,triangular silver nanoplates prepared by seed growth method had no such shortcoming.Silver nanoplates used as suspension aggregates and solid aggregates substrate in SERS detection could greatly improve the minimum detection limit of Rhodamine 6G.(10-11 M and 3.125x10-7 M,respectively),and there is a good linear relationship between Raman peak intensity and Rhodamine 6G concentration.In addition,when the wavelength of the excitation light coincides with the LSPR peak of the silver nanoplates,the surface plasmon resonance will be excited to the utmost extent,and the enhanced electromagnetic field maximizes the Raman scattering.Further,by compounding the graphene hydrogel in the solid aggregate,adding PEG-SH to the suspension aggregate,the SERS were optimized.3.The application of triangular silver nanoplates in polymer solar cells.By embedding silver nanoplates between the ITO and ZnO layers of the polymer solar cell,the near-field enhancement effect caused by the LSPR characteristics and the scattering of the incident light by the nanoplates are used to increase the light absorption of the device,thereby improving the photoelectric conversion efficiency(PCE)of the solar cell.To PTB7:PC71BM inverted polymer solar cell,the short circuit current density reached 9.16 mA/cm2,the open circuit voltage was 0.696 V,the FF was 57.03%,and the PCE reached 3.64%.Compared with the device without triangular silver nanoplates,the PCE was improved by 156%.