Crystallites of α-Sexithiophene in Bilayer Small Molecule Organic Solar Cells Double Efficiency

Recent efforts in research and development of small molecule based organic solar cells have led to power conversion efficiencies exceeding 10%. Understanding the incorporated interfaces in these devices is an utterly important parameter for their improvement. Here we investigate the influence of alpha-sexithiophene (alpha-6T) nanostructures on the performance parameters of alpha-6T/C-60 inverted bilayer solar cells. By in situ controlled growth, crystalline alpha-6T nanostructures are formed in the devices and a correlation between the morphology of the structures and the device performance is presented. Under certain, well-defined circumstances, we observe an efficiency increase of around 100% when implementing crystalline nanostructures.