Inkjet Printing Organic Solar Cells
L. Ren, S. Wang
Texas Tech University, US
Keywords: photovoltaic conversion, inkjet printing
Abstract:By virtue of photovoltaic effect (i.e. convert solar radiation to electrical power), solar cell is one of the promising tools for human to overcome energy crisis. Particularly, in last decade, much attention has been paid to organic solar cells because of their special characteristics including light-weight, low cost, easy processing and being flexible in comparison to traditional silicon solar cells. Many manufacturing technologies have been tried for organic solar cell, including spin coating, screen printing and doctor blading, etc.. However, they are still based ITO coated glass-substrate, and have to combine evaporation process for coating metallic electrode. In this paper, a cost-effective ink-jet printing technology was demonstrated to fabricate the whole solar cells. Specifically, carbon nanotubes(CNTs) were made to ink and printed to thin film on the plastic substrate. Subsequently, the PEDOT-PSS and P3HT: PCBM mixtures were printed onto the CNT films sequentially. Finally, the aluminum nanoparticles were functionalized and dispersed into organic solvent, and then printed onto the P3HT: PCBM layer as a cathode. Atomic Force Microscope (AFM) and Scanning Electron Microscope (SEM) were utilized to characterize the morphology of heterojunction and electrodes. The surface resistivity of printed CNT and aluminum electrode were also investigated. In addition, ITO-based regular organic solar cells were fabricated by combination of spin-coating and evaporation to compare the performance. The solar cells fabricated by inkjet-printing and spin-coating showed similar photovoltaic properties. Therefore, the inkjet printing is proved to be an environment-benign and robust method for solar cell fabrication.