NOVELTY - The method comprises: providing a substrate (110); forming an indium thin oxide (ITO) layer (120) on the substrate, where the ITO layer comprises an anode; solution depositing a hole transport layer (HTL) layer (130) on the ITO layer, where the HTL layer comprises an amorphous, p-type metal oxide; forming an active layer (140) on the HTL layer, where the active layer comprises a donor region and an acceptor region; and forming a contact portion on the active layer, wherein the contact portion comprises a cathode. The HTL layer comprises p-type nickel(II) oxide (NiO).    USE - The method is useful for fabricating an organic photovoltaic device (claimed) including an organic solar cell, and an electronic device including organic light emitting diode and organic transistor.    ADVANTAGE - The organic photovoltaic device is fabricated with excellent power conversion efficiency and controlled interfaces.    DETAILED DESCRIPTION - The method comprises: providing a substrate (110); forming an indium thin oxide (ITO) layer (120) on the substrate, where the ITO layer comprises an anode; solution depositing a hole transport layer (HTL) layer (130) on the ITO layer, where the HTL layer comprises an amorphous, p-type metal oxide; forming an active layer (140) on the HTL layer, where the active layer comprises a donor region and an acceptor region; and forming a contact portion on the active layer, wherein the contact portion comprises a cathode. The HTL layer comprises p-type nickel(II) oxide (NiO) and solution deposited NiO (sNiO). The solution depositing process includes solution depositing the sNiO followed by a low temperature anneal. The step of solution depositing the sNiO includes spin-coating a diluted nickel ink followed by a low temperature anneal with the speed of 4000 revolutions per minute (rpm) for 60 seconds. The annealing process is performed at 250 degrees C for 1 hour, and the sNiO comprises a thin-film. The method further comprises: exposing the HTL layer to oxygen plasma after solution depositing the HTL layer; exposing the HTL layer to an oxygen-plasma treatment after solution depositing the HTL layer; and forming a transparent conducting oxide (TCO) layer on the substrate.    DESCRIPTION OF DRAWING(S) - The figure shows a schematic view of an organic photovoltaic device.    Organic photovoltaic device (100)    Substrate (110)    ITO layer (120)    HTL layer (130)    Active layer. (140)