<p>The special features like dispersion, suspension, and stability which mainly contribute to the thermophysical properties of nanofluid play a crucial role in its application as heat exchanger fluid in solar energy harvesting devices. As an anti-agglomeration tool, ultrasonic waves significantly activate the nanoparticles in base fluid like water to execute its properties for exchange of heat flow in a medium. Preparation techniques and rheological properties, sonication time significantly results in enhancement of heat transfer efficiency. Two-step process has been followed for synthesis of different volume fractions of 0.01–0.05% to explore the sensitive presence of nanoparticles. Synthesis of nanoparticles has been performed with leaf extract of lemongrass (Cymbopogon citratus) vide active participation of ultrasonic wave. The different experimental technique for confirmation of crystal structure, surface morphology, and spectroscopic and particle analysis is employed to study the impact of sonication on lemongrass extracted TiO₂ nanoparticles for intense analysis on effect of ultrasonication in maintaining their stability and thermal properties. Thermal conductivity of said volume fraction was measured for different sonication times (0–180&#xa0;min), and the results are compared with that of proposed theoretical models for validation. The highest thermal conductivity was observed at 180 min sonication period for volume concentration 0.05% with an enhancement of 16.85%.</p>