In this article, InP quantum dots (QDs) are synthesized with a green methodology. The preparation of the InP QDs is demonstrated by varying the ratios of the precursors used such as InCl3 and trioctylphosphine (TOP). These QDs are fabricated through the application of TOP (as phosphorous source and reducing agent for the In salt) for forming indium and to develop the targeted InP QDs, which are characterized using HRTEM, XRD, PL, FTIR, UV–Vis, and time resolved spectroscopy. A rapid reaction time (~ 30 min) procedure in a single pot at a temperature of ~ 310 °C is developed. InP QDs with particle sizes varying from 4 to 6 nm have been measured with different concentrations of InCl3 and TOP. InP QDs yield reached 23%. Zincblende crystal structure is recognized for InP with high orientation plane of (220) as confirmed with XRD and confirmed with SAED. Solar cell devices are built by anchoring the InP QDs onto a TiO2 layer and measure the photovoltaic performance and spectral response of the device built on FTO/glass substrate. TiO2/InP QDs solar cell devices are fabricated with high fill factor of 0.86 and open circuit voltage value of 501 mV and overall efficiency of 0.48%.