Correlation between Temperature Activation of Charge-Carrier Generation Efficiency and Hole Mobility in Small-Molecule Donor Materials

Optical display film as flexible and light trapping substrate for organic photovoltaics

We demonstrate flexible small molecular solar cells on periodically patterned plastic substrate (LCD display film) using a highly transparent poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (

PEDOT

PSS) electrode with flexible thin atomic layer deposited (ALD) AlO_x top and bottom encapsulation. The organic photovoltaic device (OPV) on this display film shows a power conversion efficiency of 7.48%, which is a 13.0% improvement as compared to a device fabricated on a planar poly-ethylen-terephtalate (PET) substrate (6.62%) and even higher than the efficiency of a device using planar glass substrate (7.15%). The improvement is mainly due to an enhanced harvesting of photons with wavelengths shorter than 500 nm. Moreover, the fully encapsulated device is sufficiently flexible to withstand a bending with a 10 mm radius for more than 50 cycles at ambient condition. These results indicate that the use of standard optical display films is a cheap, simple and efficient way to increase the photocurrent and overall efficiency of organic photovoltaic devices.