Miniaturized semiconductor devices with energy harvesting features have paved the way to wearable technologies and sensors. Although thermoelectric systems have attractive features in this context, the ability to maintain large temperature differences across device terminals remains increasingly difficult to achieve with accelerated trends in device miniaturization. As a result, a group of scientists in applied sciences and engineering has developed and demonstrated a proposal on an architectural solution to the problem in which engineered thin-film active materials are integrated into flexible three-dimensional (3-D) forms.