Simple experimental test to distinguish extraction and injection barriers at the electrodes of (organic) solar cells with S-shaped current–voltage characteristics
2013 (English)In: Solar Energy Materials and Solar Cells, ISSN 0927-0248, Vol. 117, no SI, 599-603 p.Article in journal (Refereed) Published
Adjusting the work function of the two electrodes to the energy levels of the intrinsic active materials of an organic solar cell is crucial for a good device performance. Often, injection barriers (in combination with selective contacts blocking one charge carrier species) caused by a misaligned metal work function or extraction barriers resulting from insulating intentional or unintentional interlayers between metal and active layers, result in a decrease in fill factor seen in the extreme case in S-shaped current–voltage (J–V) characteristics. To avoid this S-kink, it is essential to identify its origin, desirably applying a simple experimental method. We propose an approach based on analyses of current–voltage data as a function of illumination intensity. A normalization of the J–V curves at the saturated photocurrent reveals distinctive features for each type of barrier. We apply the method to planar heterojunction small-molecule and bulk heterojunction polymer solar cells with oxidized metal electrode or plasma-treated active layer and explain the theory with a drift-diffusion model.
Place, publisher, year, edition, pages
Elsevier , 2013. Vol. 117, no SI, 599-603 p.
Organic solar cell, S-shape, Barrier, Electrode, Drift-diffusion model, Plasma-treatment
Engineering and Technology
IdentifiersURN: urn:nbn:se:liu:diva-100304DOI: 10.1016/j.solmat.2013.07.014ISI: 000325188400090OAI: oai:DiVA.org:liu-100304DiVA: diva2:661515
Funding Agencies|BMBF (OPEG)|13N9720|Reiner Lemoine foundation||Science Council (V)||Swedish Energy Agency||Knut and Alice Wallenberg Foundation||2013-11-042013-11-042013-11-07