S-shaped current-voltage characteristics of organic solar devices

A. Wagenpfahl, D. Rauh, M. Binder, C. Deibel, V. Dyakonov
2010 Physical Review B  
Measuring the current-voltage characteristic of organic bulk heterojunction solar devices sometimes reveals an s-shaped deformation. We qualitatively produce this behaviour by a numerical device simulation assuming a reduced surface recombination. Furthermore we show how to experimentally create these double diodes by applying an oxygen plasma etch on the indium tin oxide (ITO) anode. Restricted charge transport over material interfaces accumulates space charges and therefore creates s-shaped
more » ... formations. Finally we discuss the consequences of our findings for the open circuit voltage V_oc
doi:10.1103/physrevb.82.115306 fatcat:kxrexsmf2vfffkl6e7xprvawza