Inkjet‐Printed Random Lasers

Abstract Printing technology has led to a multitude of revolutions in design, conception, fabrication, and application of optoelectronics nowadays especially for wearables and one‐off devices. Recent advances range from solar cells, batteries, sensors, LEDs, displays, biomedical widgets to smart tags. Inkjet‐printed random lasers (IPRLs), demonstrated here, fill in the crucial but missing piece of the puzzle in printed optoelectronics as well as progress in laser research. A broad emission spectrum of IPRL inks covering more than 75% gamut of CIE color space is successfully exploited and well adopted by commercial desktop inkjet printers. Furthermore, based on the digital, ink‐efficient, mask‐free patterning, and drop‐on‐demand printing technique, a series of long‐anticipated proofs‐of‐concept including on‐chip laser lighting modules, red‐yellow‐green‐blue pixel‐based laser displays, and ink‐crypto/laser‐coded security printing technique are also demonstrated.