A City College of New York (CUNY) research team has demonstrated an LED based on half-light, half-matter quasiparticles in atomically thin materials. The device was fabricated using stacks of atomically thin semiconductor materials embedded in an optical cavity. The electrically driven polariton LED operates at room temperature using monolayer tungsten disulfide (WS2) as the emissive material. The polariton LED demonstrated an extracted external quantum efficiency of about 0.1%. According to the researchers, this number is comparable to recent demonstrations of bulk organic and carbon nanotube-based polariton electroluminescence devices. Schematic of a half-light, half-matter quasiparticle-based LED developed using atomically thin materials. Courtesy of Visakh Menon. Achieving the electrical injection of polaritons is attractive both as a precursor to realizing electrically driven polariton lasers and for achieving ultrafast microcavity LEDs. “The fact that this device is fabricated using stacks of atomically thin materials and operates at room temperature makes it an important first step toward a technologically relevant device demonstration,” professor Vinod Menon said. “One potential application of such hybrid LEDs is the speed of operation — which can translate to using them for LED-based communication systems including LiFi.” LiFi (light fidelity) is a wireless optical networking technology that uses LEDs for data transmission. The research was published in Nature Nanotechnology (https://doi.org/10.1038/s41565-019-0543-6).