For the first time, scientists have revealed new graphene light-emitting devices with tunable spectra

Recently, a group led by Professor Tian Ling of Microelectronics at Tsinghua University published an article titled "Spectrally tunable all-graphene (Spectral tunable all-graphene)" in Nature Communications. -based flexible field-effect light-emitting device "), for the first time revealed a light-emitting device capable of regulating the emission wavelength by voltage. Unlike conventional fixed-wavelength LEDs, this new device, which emits wavelengths (within a single device) continuously between 750nm and 450nm, breaks the existing color synthesis of display devices and is expected to demonstrate the benefits of contemporary displays, lighting and Communication technology has a revolutionary impact. Wang Xiaolu, a postdoctoral fellow at Yale University, and Tian He, a Ph.D. graduate in micro-nanoelectronics at Tsinghua University, are co-authors of the article. Professor Ren Tianrun, a professor of micro-nanoelectronics at Tsinghua University, is the author of the paper.

The spectrum of the emission wavelength is regulated by the gate voltage.

To date, the luminescence color / wavelength of all LED devices is determined by the luminescent material. For existing LEDs, once the device is prepared, its emission wavelength is fixed. Conventional display or lighting technology achieves color representation or white light synthesis by adjusting the brightness of light-emitting units in several fixed colors (typical devices using the three primary colors of red, green and blue). The first wavelength / color-adjustable LED reported in this article achieves excellent color fidelity while significantly reducing the number of light-emitting cells in a display device, greatly optimizing the driver circuit and reducing power consumption, which The results have far-reaching implications in related fields. Paper reviewers commented that "this work is expected to expand into new research areas in the field of light-emitting devices" and "this work is exciting and influential."

Regulating the emission wavelength by gate voltage mechanism diagram.

Graphene materials, with unique physical properties, are widely used in controlled photon / optoelectronic devices and other topics. However, graphene-based light-emitting devices are a difficult field and long-term blank field in academia due to their characteristics of zero band gap and non-luminescent recombination rate. Ren Tianling professor's group innovative through laser direct writing technology, the graphene oxide and graphene at the interface of the interface to obtain a half-reduced srGO material. The material combines the high conductivity of graphene with the wide bandgap characteristics of graphene oxide. By constructing an in-plane gate structure, the Fermi level of srGO can be modulated by applying a voltage to the gate, thereby controlling the center wavelength of the graphene LED emission in real time. The LEDs also feature high brightness and flexible devices making them ideal for modern LED display, lighting and communications technologies.

In recent years, Professor Ren is devoted to the research of two-dimensional electronic devices such as graphene, paying particular attention to new devices that break through the limits of traditional devices and laying the foundation for a new generation of micro-nano electronic devices. In the new graphene-based memories, acoustic devices and sensing devices And other aspects have been a number of innovative achievements, such as flexible transparent graphene headphones and low-power graphene resistive memory. The research results have been supported by the National Natural Science Foundation of China.