Detection of trap charge in small molecular organic bulk heterojunction solar cells
Debdutta Ray, Lorenzo Burtone, Karl Leo and Moritz Riede, USA (2010)
We detect and measure the trap charges in a small molecular bulk heterojunction (BHJ) solar cell under operating conditions. The trap charge density is estimated from capacitance measurements with light incident on the sample. At high intensities (~ 1 sun, 100 mW/cm2), the trapped charge concentration leads to a spatial distortion of the electric field in the device. The lower limit of the trap charge density is estimated to be 6x10^16 cm^-3. The frequency dependence of the capacitance suggests that the charges are trapped in a manifold of deep states present in the energy gap of the semiconductors. The distortion of the electric field by this trap charge affects the charge carrier collection efficiency.
Partners : TUD
Place of Publication : USA
Date of Publication : 2010/09/07