Recombination losses in organic solar cells : Study of recombination losses in organic solar cells by light intensity-dependent measurements

• Main Author: Lind, Sebastian
• Format: Others
• Language: English
• Published: Karlstads universitet, Institutionen för ingenjörsvetenskap och fysik (from 2013) 2018
• Subjects: Organic solar cells; recombination losses; Engineering and Technology; Teknik och teknologier
• Online Access: http://urn.kb.se/resolve?urn=urn:nbn:se:kau:diva-68584

Easy manufacturing, light weight and inexpensive materials are the key qualities of organic solar cells that makes them a highly researched area. To make organic solar cells adequate for the market, the efficiency of power conversion has to increase further, and the lifetime of organic solar cells has to improve. Avoiding recombination losses is a piece in the puzzle that can make organic solar cells more efficient. Organic solar cells with two different hole transport layers were therefore examined by I-V measurements. It was found that the organic solar cell with MoO3 as the HTL possesses a higher current density in both the reverse region and forward region. The higher current density in both regions points towards a less successful blocking of electrons travelling to the anode (reverse region) and a better ability to transport holes from the active layer to the anode. Insight to different state of recombination was also found from the slope values in the Voc and Jsc as a function of light intensity plots. It was concluded that both solar cells experience a dominant monomolecular recombination under short circuit condition and evolved into bimolecular recombination under open circuit condition. However, the cell with CuSCN showed a more dominant bimolecular recombination, which was shown from a slope closer to one unity kT/q in the Voc as a function of light intensity plot.