We present here for the first time the fabracition of a p-Cu2O/ZnO/AZO flexible heterojunction solar cell by electrodeposition of Cu2O thin film on a plastic substrate and sputtering of ZnO:Al layer. The Atomic Layer Deposition (ALD) has been employed to insert 5 nm ZnO as buffer layer. The heterojunction solar cell was characterized by Raman spectroscopy and scanning electron microscopy that show pyramidal shape and phonon modes for Cu2O thin film. Current voltage (J-V), capacitance voltage (C-V) and the external quantum efficiency (EQE) measurements were performed to understand the heterojunction properties. The solar cell device exhibits a power conversion efficiency of 0.897 +/- 0.005% with an open circuit voltage of V-oc=300 mV, a short circuit current density of J(sc) = 6.819 +/- 0.048 mA cm(-2) and a fill factor of FF = 0.439 +/- 0.006. The values of the built-in potential and the acceptor concentration at the junction were estimated from the reverse bias C-V measurement to be 0.37 V and 6.67 x 10(16) cm(-3), respectively. (C) 2015 Elsevier Ltd. All rights reserved.