Thermophotonic cooling with light-emitting diodes

The currently ubiquitous light-emitting diodes (LEDs) have revolutionized the lighting industry. Contrary to common belief, however, LEDs are much more than just simple electricity-to-light converters. They are solid-state thermodynamic machines, theoretically capable of continuous and near-reversible energy conversion between electrical, thermal and optical energy. For over 50 years, the possibility of exploiting LEDs as efficient solid-state coolers has remained largely out of reach due to the high-material-quality requirements and commercial focus on light emission. Recent promising advances in electroluminescent cooling by LEDs, however, suggest that the remaining challenges in the area may be surmountable and practical cooling could be feasible. This Perspective discusses recent achievements in electroluminescent cooling, outlining the expected promise, the remaining challenges and their potential solutions.