In this work, quercetin/p-InP heterojunction solar cell has been fabricated via solution-processing method and characterized by current–voltage and capacitance–voltage measurements at room temperature. A barrier height and an ideality factor value of 0.86eV and 3.20 for this structure in dark have been obtained from the forward bias current–voltage characteristics. From the capacitance–voltage measurement, the barrier height and free carrier concentration values for the quercetin/p-InP device have been calculated as 1.63eV and 3.8×10 17 cm −3 , respectively. Also, series resistance calculation has been performed by using Cheung theory. The device exhibits a strong photovoltaic behavior with a maximum open circuit voltage V oc of 0.36V and short-circuit current I sc of 35.3nA under 120lx light intensity only.