We present fabrication and characterization of flexible high voltage dye-sensitized solar cells (DSSCs) by screen printing of porous ZnO photoelectrode to power up IoT (Internet of Things) nodes to substitute batteries. Combination of triphenylamine based organic dye, D35, and [Co(bpy)(3)] (2+/3+) (bpy = 2,2'-bipyridine) redox electrolyte achieved high voltages approaching 1 V, owing to strong rectification of charge transfer processes by passivation of the ZnO surface by the adsorbed D35 layer. The system, however, suffered from limited diffusion of the Co complex redox couple within the porous photoelectrode, causing saturation of photocurrent and poor fill factor to limit the overall conversion efficiencies under high light illumination. The current/voltage linearity was improved by optimizing the thickness of porous ZnO layer and by use of low viscosity electrolyte solvent. The highest conversion efficiencies we obtained were 3.73 and 2.63% for the cells employing F-doped SnO2 (FTO) coated glass and indium tin oxide (ITO) coated poly-ethylenenaphthalate (PEN) film substrates, respectively. (C) The Author(s) 2018. Published by ECS.