Solid-State Lighting Technologies: Operating Principles, State of the Art, and Future Challenges

Electrical lighting uses approximately 13.7% of the world’s electricity and heavily impacts humans’ visual performance and also well-being, health, and security. Electrical power light sources and lighting systems impact also our planet’s resources and our biotope. After decades of stagnation of the performances of legacy lighting technologies, products based on solid-state lighting (SSL) technology have become the most efficient light sources by far that we can find on the market today. Indeed, the advent of SSLs is considered to be the third revolution in the domain. Today, SSL products and especially light-emitting diodes (LEDs) are mature and are on the way to dominating a market worth more than US$120 billion. Even if someone can argue that innovation in the domain of LED products has been decelerating for the last couple of years, large-surface, flexible, organic light-emitting components open up new fundamental and technological challenges and offer unsuspected horizons for the light designers of the next decade. Further, the fourth revolution in lighting is looming: the advent of intelligent and sustainable lighting systems that could transform the way we conceive of the generation of artificial light, by associating it with information and communication technologies, the Internet of Things, technologies that are transforming our society and are taking a prominent place in everyday life. This review article focuses on LED and organic LED technologies. It explains the basic operating principles, highlights the state of the art, and indicates the main challenges for the next decade. Other articles in this <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">IEEE Industry Applications Magazine</i> special issue are devoted to extinguishing legacy technologies and raising sustainable smart lighting systems.