Achieving bright light emission across the spectrum with pulsed electroluminescent devices

The scope of luminescent materials used in light-emitting devices is often limited by material processing and band alignment concerns. We have developed a capacitive device structure with a single injection contact which can generate bright electroluminescence from a wide range of materials, simply by depositing the luminescent material on top of the device. Charge injection is achieved across different band alignments by applying pulsed voltages across the metal-oxide-semiconductor capacitor structure. By using carbon nanotube networks as the injection contact, emission can be produced from vast libraries of nanomaterials across the ultraviolet to infrared energy range without additional charge injection layers. Light emission can be observed at high frequencies at voltages near the optical gap of the emissive material by employing a thin high-k gate oxide layer. Due to the compatibility of the device with non-uniform and arbitrarily shaped active layers, scalable fabrication of large device arrays can be achieved. Multiplexed electroluminescent arrays with emission spanning a broad spectral range may enable new opportunities in optoelectronics and spectral measurement, of which a few examples are discussed.