| During the past decade,nanotechnology has drawn considerable attention of researchers by designing new nanostructures which can enhance the performance of solar cells.The synthesis of metallic nanostructures that support surface plasmon resonance(SPR)with improved light trapping efficiency has gained much consideration owing to their strong scattering and near-field enhancement.In this thesis,the preparation of gold nanoparticles(AuNPs)by rapid annealing of gold film was studied.The gold nanoparticles were coupled to the surface of the solar cell by rapid annealing of gold film and boiling gold colloidal nanoparticles on the surface of the solar cell.The effect of gold nanoparticles on the solar cell efficiency was investigated.The morphology and distribution of as synthesized gold nanoparticles were studied by the interaction of gold film thickness,annealing temperature and annealing time.Under considerable growth parameters,such as film thickness 4 nm,annealing temperature 400℃and annealing time 30 s,our synthesized NPs were uniform,well dispersed and have very good optical properties.Compared to other techniques,the thermal annealing is relatively non-time consuming and less cost effective.Moreover,this annealing process is well matched with the preparation of the GaAs solar cell ohmic contact.After a layer of AuNPs is introduced on the surface of GaAs to fabricate the solar cell.Based on our result an increase in short-circuit current density from 11.30m A/cm~2to 11.95m A/cm~2 was observed and overall 5.8%increase in short-circuit current density was observed.On the other hand,colloidal AuNPs suspension in different concentration ranging from 50 ul to 200 ul were deposited by the"boiling deposition"method.With the increase of solution concentration,the short circuit current density increased to certain extent.However at concentration of 100 ul gold nanoparticle suspension,the maximum(7.9%)increase in short-circuit current density was observed.Based on our experimental findings we can conclude that the solar cell performance can be enhanced by coupling AuNPs to the solar cell surface.Finally,we used the finite-difference time-domain method to explore the physical mechanism of enhancement of surface plasmon solar cells and provide a theoretical results to support results.Analysis shows that AuNPs can be used to enhance the absorption of specific wavelengths by using appropriate density as well as controlling the size of the NPs.As with the increase of particle size and periodic spacing,the optical enhancement effect first increases and then decreases.However,for a specific metal material,the particles size,array and optimum density are the key parameter that can maximizes the NPs light absorption for the solar cell. |
