An Electricity-Generating Window Made of a Transparent Energy Harvester of Thermocells.

Windows are primarily for admitting light or air and allowing people to see out. Presented here are windows that can generate electricity while retaining the primary functions. These windows are made of transparent thermocells that convert a temperature difference across the window to electricity. Interconnected p-type and n-type or p-n thermocells are introduced and utilized to scale up the output power of a thermocell window (T-window). The T-window consisting of 2 p-n thermocells provides an output voltage of 60 mV and a power density of 0.5 μW/cm2 for a small temperature difference of 10 °C with an optical transparency of ∼50% in the visible range. The T-window introduced here could pave the way to enhancing energy efficiency in residential environments by capturing naturally available low-grade heat, a new renewable energy source that is otherwise discarded to the surrounding environment.