ECE engineers have introduced a 3D nanoscale imaging technique that reveals how advanced materials convert light into electricity—separating, in real space, the photovoltaic (PV) and photothermoelectric (PTE) contributions that often mix in tiny devices. Led by ECE faculty Ming Liu and CEE faculty Ruoxue Yan and published in Science Advances (link: https://www.science.org/doi/10.1126/sciadv.adv7614), the work maps PV and PTE in MoS₂–gold nanodevices using a near-field probe, uncovering that heat-driven PTE currents extend far beyond the metal contact—contrary to conventional wisdom. By adding a thin h-BN layer to steer lateral heat flow, the team boosts PTE response, pointing to smarter, faster photodetectors and more efficient solar technologies where managing both light and heat is essential.