Research Of Metallic Nano-particles Based On Surface Plasmon And High Efficiency HIT Solar Cells

Currently, the two biggest problems in development of solar cells are improvingthe conversion efficiency and reducing the cost, which are also the importantprocesses in promoting the PV industry gradually. As an indirect band gapsemiconductor, silicon has a weak light absorption near the band gap. For traditionalsilicon-based solar cells, it can’t meet the requirements of high conversion efficiency.New research results show that the metal nanoparticles have a significant surfaceplasmon resonance effect. Owing to its unique properties of light scatteringenhancement, it is possible to improve the conversion efficiency in thin film solarcells by this method. As the size, shape and structures of nanoparticles (NPs) willinfluent the intensity and position of surface plasmon, it is meaningful for applicationsto optimize metallic nanostructures of different size and shape to achieve moreefficient solar cells. In this paper, surface plasmon optical properties of two kindsdifferent nano-structures have been discussed. The main results are summarized asfollows:1、 Ag NPs were prepared by magnetron sputtering method in differentconditions. The sputtering time and annealing temperature are two importantparameters affecting the Ag nanoparticles. We can distinctly observe Ag nanoparticlesurface plasmon resonance characteristics by the transmittance measurement. Theparticle size, shape, and spacing of Ag particles both impact the resonant absorptionpeak location.2、 The localized surface plasmon properties of Ag NPs and Ag@Al2O3coreshell NPs with core radii ranging from20~120nm were analyzed by Miescattering theory. Using numerical simulations, we show that an increasing shellthickness for core-shell NPs results in a red-shifted plasmon resonance peakcompared to Ag core NPs. An averaged scattering efficiency under AM1.5illumination is used to characterize the scattering abilities of different NPs. ForAg@Al2O3core-shell structures, the averaged scattering efficiency increases andsubsequently decreases with increasing shell thickness due to the competinginfluences of plasmon hybridization and phase delay. For larger radii NPs, such asR>100nm, the scattering abilities of core-shell structures are superior to those of spherical Ag NPs.3、 The β-FeSi2/c-Si(p)/μc-Si(p+) heterojunction solar cells was analyzed anddesigned by AFORS-HET software. The influences of the characters of emitter andback surface field (BSF) on the conversion efficiency of solar cell were discussed.The simulation results show that the increase of the thickness of the emitter willdecrease the short-current density and affect the conversion efficiency of solar cell.The emitter doping concentration is another key parameter of heterojunction solarcells. We can’t ignore the influence of the interface states density. MicrocrystallineBSF can increase conversion efficiency compared with solar cell with no BSF.