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.

No abstract

No abstract

Fabrication of these devices requires patterning the conductive polymer films deposited on a flexible substrate. Various approaches to pattern polymers have been developed for forming complicated topological patterns to create novel devices, as well as to enhance device performance. [3] Photolithography, sequentially combined with reactive ion etching, is currently the primary technique used for wafer-scale, high-resolution patterning of polymers, [4] although the issues of temperature tolerance and chemical degradation during the lithography and etching processes should be addressed for the use of various combinations of conductive polymers and plastic substrates. To improve the compatibility

A thermocouple is the most widely used electrical component for cost‐effective measurement of temperature in both academia and industry. However, its low sensitivity with typically tens of microvolts per Kelvin needs to be improved to obtain precise measurements. Introduced here is an ionic thermocouple to provide the level of accuracy required of temperature measurements in medicine, precision agriculture, smart buildings, and industrial processes. Ionic conductors are utilized in place of the electrical conductors typically used in the conventional thermocouples (TCs). The ionic thermocouples (i‐TCs) are demonstrated with redox reactions of 10 × 10−3 m potassium ferri/ferrocyanide and 0.7 m iron(II/III) perchlorate, which are electrolytes used as p‐type and an n‐type elements, respectively. The voltage output of the i‐TC that is generated by a change in temperature is approximately two orders of magnitude larger than that of the conventional TC, providing almost two more significant figures in measured temperature. The i‐TC can easily be miniaturized as demonstrated for the in situ temperature measurement of the fluid flowing in the channel of a microfluidic device. A flexible and stretchable i‐TC device is also demonstrated to stably operate up to a tensile strain of 23% with no noticeable degradation in performance.