Understanding S-shaped current-voltage characteristics of organic solar cells: Direct measurement of potential distributions by scanning Kelvin probe

作者：Saive Rebecca^*; Mueller Christian; Schinke Janusz; Lovrincic Robert; Kowalsky Wolfgang

来源：Applied Physics Letters, 2013, 103(24): 243303.

DOI：10.1063/1.4846615

We present a comparison of the potential distribution along the cross section of bilayer poly (3-hexylthiophene)/1-(3-methoxycarbonyl) propyl-1-phenyl[6,6] C61 (P3HT/PCBM) solar cells, which show normal and anomalous, S-shaped current-voltage (IV) characteristics. We expose the cross sections of the devices with a focussed ion beam and measure them with scanning Kelvin probe microscopy. We find that in the case of S-shaped IV-characteristics, there is a huge potential drop at the PCBM/Al top contact, which does not occur in solar cells with normal IV-characteristics. This behavior confirms the assumption that S-shaped curves are caused by hindered charge transport at interfaces.

• 出版日期2013-12-9