Integrated Infrared Sensing Arrays Based on Ice-Templated Vertically Aligned Reduced Graphene Oxide

Economical, fast, and sensitive infrared (IR) sensing is essential for noncontact temperature measurement and imaging, which is crucial for a wide range of applications. In this work, we design a bolometer based on vertically aligned reduced graphene oxide (VRGO) thin films by combining oxygen-containing functional groups with vertically aligned microstructures. VRGO films feature low density (4.8-6.4 mg cm-3), ultralow thermal conductivity (1.93 mW m-1 K-1 in vacuum at 295 K), low resistivity (0.38 Omega<middle dot>m), and moderate temperature coefficient of resistance (TCR, -0.14% K-1 at 295 K), which give them greatly enhanced bolometric performance compared to graphene. The electrical and thermal transport of VRGO films from 320 to 15 K is investigated and compared with horizontally stacked RGO films. Moreover, the VRGO films exhibit high sensitivity, fast response, and good repeatability in response to radiation from a laser, blackbody radiator, and human hand. Using ice template growth and laser-assisted manufacturing, the VRGO film can be easily extended to detector arrays. The pixelated image from the 2D sensor array successfully maps the shape of the heater. Without the need for additional IR absorption and thermal isolation structures, the integrated VRGO film array can benefit lightweight and low-cost applications, such as thermal imagers in drones and wearable devices.