Optimized Design Of Plasmonic Nanoparticles For Light Absorption Enhancement In Organic Thin Film Solar Cells

The massive exploitation of fossil fuels has caused a series of serious environmental problems such as global warming and air pollution.Therefore,finding suitable alternative energy is an important topic.Photovoltaic(PV)technology can convert solar energy into clean energy by designing and preparing efficient solar cells.Photovoltaic devices have been developed to three generations from traditional silicon-based solar cells to date.At present,organic thin-film solar cells are one of the research focuses of the third-generation photovoltaic devices,however,the weak intrinsic absorption of the active layer limits further improvements in efficiency of cells.The full utilization of sunlight is one of the necessary conditions for the realization of high efficiency solar cells.By using local surface plasmon resonances(LSPRs),the incorporation of metal nanoparticles into the active layer of organic thin film solar cells can effectively improve the light absorption capacity without increasing the extra thickness of the cells.In order to optimize the metal nanoparticles incorporated into solar cells for obtaining the maximum light absorption,we systematically studied the effect of metal particles on the light absorption of the active layer by finite element methods(FEM).Finally,it was found that the dosage of plasmonic metals is an important factor for light absorption enhancement in thin-film OSCs.When the total plasmonic dosage remains unchanged,an almost equivalent enhancement effect is achieved regardless of high concentrations of small NPs or low concentrations of large NPs.The physics behind is attributed to the spatial averaging of plasmonic near-field enhancement effects.In addition,metal materials tend to react with the medium in experiments,which is detrimental to the cells’ long-term operation.In order to maintain the stability,a thin dielectric protective coating is usually coated on the surface of the metal particles.However,the introduction of dielectric coating reduces the effective volume of the active layer,which may result in the decrease of absorption enhancement.Therefore,the effect of dielectric coating on absorption enhancement is simulated numerically.Our results show that the absorption enhancement decreases more slowly when the dielectric coating of high refractive index is used than that corresponding to the low index materials.The physics behind is addressed within classic electrodynamics.These series of results extend our knowledge of plasmonic solar cells and help to achieve more efficient organic solar cells.