Carbon based perovskite solar cells have been constructed by screen-printing three subsequent mesoporous layers of Titania, Zirconia and Carbon without a hole transporting layer and by infiltration of perovskite liquid precursor through the layers. Cell efficiency was optimized by varying the thickness of the three layers and the composition of the inks employed for screen printing. Electrochemical impedance spectroscopy was employed as a guide in the search for layer thickness optimization. All cell construction and testing was carried out under ambient conditions of 20-30% humidity. The cells were not encapsulated. The best cell gave an efficiency of 10.7%. All cells demonstrated a remarkable stability supported by the low ambient humidity and the hydrophobic, therefore protective, nature of the carbon top component. (C) 2018 Elsevier Ltd. All rights reserved.