Study On Electrical Properties Of Organic Solar Cells Based On Universal Mobility Model

Organic solar cells,as representatives of the third generation of solar cells,have witnessed remarkable advancements in energy conversion efficiency in recent years.Their unique characteristics,including facile fabrication,low cost,and excellent flexibility,make them highly promising for solar cell commercialization.However,despite the progress made in the development of organic solar cell donoracceptor materials and thin film synthesis methods,further enhancements in the theoretical understanding of carrier transport processes within organic semiconductor materials are required.The lack of comprehensive studies describing the carrier transport mechanism poses a significant knowledge gap in the field of organic solar cells.Consequently,this thesis aims to address this gap by undertaking a thorough analysis of theoretical modeling concerning carrier transport mechanisms in organic solar cells.The primary focus areas encompassed within this research include the introduction of relevant theories associated with organic solar cells and carrier transport.These encompass the working principle of organic solar cells,device structure,carrier generation models,drift diffusion models,carrier statistical distribution,mobility models,carrier complex models,and boundary conditions.By employing the drift-diffusion model,this research presents a theoretical modeling approach to elucidate the transport mechanism within organic solar cells.The model integrates the simplex Fermi distribution,an improved universal mobility model,actual solar spectrum,indirect composites,and boundary conditions,along with the absorption coefficients of non-fullerene materials.To obtain convergent analytical solutions for the theoretical model,three approximations were implemented: the electric field strength approximation,the average carrier concentration approximation,and the constant coefficient approximation.The proposed model was then implemented using MATLAB software for programmed solution.The theoretical model was validated by calculating the current-voltage curves and open-circuit voltage-light intensity curves for ten different high-efficiency organic solar cell types.Additionally,the short-circuit current-light intensity curves for the first cell type were also computed.The calculated current-voltage curves exhibited excellent agreement with experimental data,further confirming the accuracy of our theoretical model.Similarly,the other two curves demonstrated satisfactory alignment,substantiating the validity of our proposed model.Subsequently,we analyzed the spatial distribution of carrier concentration,mobility,and simplicity coefficient for the PTQ10:m-BTP-Ph C6 solar cell under short circuit and open circuit conditions.Furthermore,we investigated the effects of light intensity and temperature on carrier concentration and mobility.Finally,we explored the impacts of built-in potential,anode/cathode potential barrier,energy disorder,and active layer thickness on device performance by varying the parameters of our model.These investigations provided insights into potential avenues for further optimization of organic solar cell performance.