Efficient fully blade-coated perovskite solar cells in air with nanometer-thick bathocuproine buffer layer

Fully printed perovskite solar cells (PSCs) were fabricated in air with all constituent layers, except for electrodes, deposited by the blade coating technique. The PSCs incorporated, for the first time, a nanometer-thick printed bathocuproine (BCP) hole blocking buffer using blade coating and deposited at relative humidity up to 50%. The PSCs with a p-i-n structure (glass/indium tin oxide (ITO)/poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS)/CH3NH3PbI3/[6,6]-phenyl-C-61-butyric acid methyl ester (PCBM)/BCP/Ag) delivered a maximum power conversion efficiency (PCE) of 14.9% on an active area of 0.5 cm(2) when measured under standard test conditions. The PSCs with a blade coated BCP delivered performance of 10% and 63% higher (in relative terms) than those incorporating a spin coated BCP or without any BCP film, respectively. The atomic force microscopy (AFM) showed that blade coated films were more homogeneous and acted also as a surface planarizer leading to a reduction of roughness which improved BCP/Ag interface lowering charge recombination. The demonstration of 15% efficient devices with all constituent layers, including nanometer-thick BCP (similar to 10 nm), deposited by blade coating in air, demonstrates a route for industrialization of this technology.

Automated summary

Fully printed perovskite solar cells were fabricated in air with all layers except electrodes deposited by blade coating technique. A nanometer-thick printed bathocuproine (BCP) hole blocking buffer was incorporated for the first time, resulting in improved performance. Blade coated BCP films were found to be more homogeneous, smoother, and contributed to better BCP/Ag interface, leading to reduced charge recombination and higher efficiency.