If the solar cell is transparent, it can generate solar power in various environments such as building window glass, car front glass, eyeglasses, human skin, and greenhouses.Therefore, it is expected to contribute to solving energy problems and environmental problems.However, most of the conventional transparent solar cells have a visible light transmittance of about 60% or less, and most of them are "semi-transparent solar cells" whose existence can be clearly confirmed visually.

　The research group focused on transition metal dichalcogenides (TMDs), which are two-dimensional semiconductor sheets with atomic thickness. In 2, he proposed a new power generation mechanism for TMD called Schottky power generation.This time, using an indium tin oxide (ITO) electrode as a transparent electrode, we succeeded in developing a highly transparent solar cell with a visible light transmittance of about 2017%, which is almost invisible to the naked eye.

　Furthermore, we found the optimum structure of the nanoscale basic unit of the TMD solar cell, and demonstrated that by integrating these into 1 cm2, it is possible to generate power (420 pW) at a level that can drive a practical device.In the future, we are proceeding with large-scale modularization by connecting multiple boards, and are considering the realization of high-power power generation that can drive many practical devices.

　With the technology developed this time, it will be possible to generate minute energy in various living environments around us in the future, and we can expect innovative social contributions that can solve energy problems and environmental problems at the same time.

Paper information:[Scientific Reports] Fabrication of near-invisible solar cell with monolayer WS2