A groundbreaking research study led by Professors Yang Ji-woong and In Su-il has unveiled a novel synthesis principle for eco-friendly ternary quantum dots, particularly focusing on the semiconductor material CuInS₂. These quantum dots, known for their ultra-small size and exceptional light absorption and emission capabilities, have traditionally been hindered by the presence of heavy metals detrimental to health and the environment. The team at DGIST, in collaboration with Dr. Ahn Hyung-joo, successfully identified the synthesis mechanism of CuInS₂, enabling the development of a photoelectrochemical device that utilizes these quantum dots for highly efficient hydrogen production using sunlight. Through meticulous control of the synthesis process, the research team achieved a quantum dot-based system that demonstrates superior hydrogen production activity, positioning it as a leader in eco-friendly quantum dot technology. Employing advanced analytical techniques like real-time X-ray scattering analysis, the team deciphered the intricate formation pathways of the ternary CuInS₂ quantum dots, overcoming the challenges posed by the simultaneous reaction of three elements in the synthesis process. The implications of this research extend beyond hydrogen production, as the proposed synthesis method opens doors for the integration of eco-friendly quantum dots in various optoelectronic devices, including displays, solar cells, and photosensors. Prof. Yang highlighted the significance of this achievement, emphasizing the potential for widespread application of eco-friendly quantum dots in semiconductor technologies and future hydrogen energy systems. The study represents a major leap in sustainable semiconductor innovation and holds promise for a greener and more efficient future in energy production.