Polymer Solar Cells Based On Surface Plasmon Resonance

Conjugating conductive polymer materials have been absorbed attentionsbecause of its flexible, fabricability, semiconductor and conductivity properties。Withthe in-depthstudy of conductive polymers and application in the scope of solar cellcomponents, research and development of low-cost polymer solar cells has beenbecoming an investigation focus. But the power conversion efficiency of polymersolar cells is still lower than inorganic solar cells due to the narrow absorptionspectrum of polymer and the low utilization rate. In addition, comparison to inorganicsemiconductor material, low carrier mobility and short diffusion distancethe polymermaterials cannot be avoidable. One significant method is synthesising new polymermaterials with low bandgap, wide absorption spectrum and high absorptioncoefficient. Another method is designing light trapping structure to improve the lightabsorption, including plasma, photonic crystals and grating structure. By limiting thetransmission characteristics of the incident light and effectively limiting the lightinside the polymer active layer materials, light absorption and the efficiency of devicecan be improved obviously.Recently, some researchers have been interested in thelight trapping effect of metal nanoparticles surface plasma.In this dissertation, by studying the production process of metal nanoparticles,one ingenious way of thermal evaporation depositon in vacuum is utilized to producemetallic nanostructures. We have investigated the improvement of polymer solar cellslight utility via the metal nanoparticles surface plasma effect systematicially.Ag nanoparticles areapplied in positive polymer solar cells. Firstly, we haveintroduced Ag nanoparticles (1nm) into the heterojunctions polymer solar cellbetween the active layer and electron transport layer by evaporation. Ag nanoparticleswere observed through the experiment (1nm) for heterojunction polymer solar celldevice to improve photocurrent and power conversion efficiency. Secondly thethermal evaporation method is used to produce silver nanoparticles. Then, the Agnanoparticles are applied in hole transport layer of positive device. It was observed inexperiment that optical current and power conversion efficiency of the device are improved due to the Ag nanoparticles (1nm). The thermal evaporation method is usedto produce silver nanoparticles. Then the Ag nanoparticles (1nm) are applied in holetransport layer and electronic transport layer of positive device. Meanwhile theposition of Ag nanoparticles in hole transport layer is optimized. Local surfaceplasmon effect and strong scattering phenomenonof double nanoparticles have beenobtained in experiment can significantly improve the performance of the device. Theefficiency was achieved2.31%, increased by roughly200%. In order to further verifythe accuracy of the experiment, we analyzed the atomic force surface morphologycharacterization, ultraviolet-visible absorption analysis characterization and validationof electrical conductivity. It is demonstrated that introducing the metal nanoparticlesin to device is beneficial to light absorption performance and electric conductivity oforganic photovoltaic devices.Ag nanoparticles are applied in inverted polymer solar cells. The TiO2electrontransport layer and preparation of TiO2nano layer using sol-gel method are brieflyexplaination. The thermal evaporation method is used to produce silver nanoparticles.The Ag nanoparticles (1nm) are applied to hole transport layer of inverted polymersolar device based on TiO2film. Short circuit current density and power conversionefficiency enhancement can be verified in experiment. Comparing with the influencein device performance of Ag film thickness (1nm,3nm,5nm,8nm,10nm), we canconcluded that1nm Ag film can improve the power conversion efficiency of deviceto3.35%significantly, increased and the enhancement is about24%. The devices areanalyzed in ultraviolet-visible absorption, complex impedance and simulated inFDTD for nearby field intensity distribution of Ag nanoparticles. It is clearly verifythat silver nanoparticles introduction can improve the performance of the device.Ag and Au nanoparticles are added into the hole transport layer of polymer solarcells device based on PSBTBT: PC71BM activel layer. We optimized the nanometerthin film thickness by producing PSBTBT: PC71BM device with different mass ratiofor the sake of maximizing the performance of the device. Firstly, Ag nanoparticleswere applied into the bulk heterojunction inverted polymer solar cells based on PSBTBT: PC71BM (mass ratio of1:1.5) to improve the shortcircuit current densityand power conversion efficiency. Comparing with the influence in deviceperformance of different Ag film thickness (1nm,3nm), it can be concluded that1nm Ag film can improve the power conversion efficiency3.55%of devicesignificantly and increased by about52%. Secondly, Ag nanoparticles are applied intothe bulk heterojunction device based on PSBTBT: PC71BM (mass ratio of1:1) topromote the short circuit current density and energy conversion efficiency. Afterintroducing1nm (i.e., Ag nanoparticles) into hole transport layer MoO3, the powerconversion efficiency of the device increased to3.15%, increased about41%. Finally,Au nanoparticles are applied into the bulk heterojunction device based on PSBTBT:PC71BM (mass ratio of1:1) to promote the short circuit current density and powerconversion efficiency. Comparing with the influence in device performance ofdifferent Au film thickness (1nm,3nm), it can be concluded that1nm Au film cansignificantly improve the power conversion efficiency of device to3.26%.