Atmospheric-moisture-enabled passive cooling and concurrent energy harvesting in photovoltaic modules

By Dr. Sunmiao Fang

Abstract

Photovoltaic (PV) modules operating in hot and arid environments often experience severe heat accumulation, which lowers their efficiency and long-term stability. In this talk, I will introduce a hybrid PV platform that combines a hygroscopic hydrogel cooling layer with a moisture-driven hydrovoltaic device. By harvesting atmospheric moisture and utilizing solar-induced waste heat, this system enables simultaneous evaporative cooling and electricity generation. The integrated design reduces PV temperature by up to 13.5 °C, enhances PV output by about 15%, and boosts hydrovoltaic performance by about 150% under illumination. This work highlights a simple and scalable route toward multifunctional solar-energy systems for distributed electronics and energy-smart buildings in extreme climates.

Lateral Semiconductor-Free-Space Gate Transistors

By Dr. Glen Maciel Garcia

Abstract

This seminar explores how nanoscale device architectures can unlock new functionalities in ultrawide bandgap (UWBG) materials beyond conventional applications. We introduce a novel lateral transistor architecture — the semiconductor–free-space gate transistor (SFGT) — in which the conventional solid gate dielectric is replaced by a free-space gate with sub-100 nm fin channels and dual side gates. This open geometry enables direct access to the channel, allowing external electric-field modulation, optical gating, and threshold-voltage tunability, while mitigating charge trapping and reliability limitations associated with conventional oxide dielectrics.

The SFGT architecture demonstrates performance comparable to oxide-gated transistors, including steep subthreshold slopes, high current, low hysteresis, and high breakdown voltage. We demonstrate the concept using β-Ga₂O₃ devices and present preliminary implementations on GaN HEMTs, highlighting that the SFGT approach is broadly applicable across material platforms.

These results establish SFGTs as a versatile architecture for next-generation UWBG electronics, sensing, optoelectronics, and power applications.