Qinghua Tian Ling Ren control devices will change the lighting wavelength or attribute

Tsinghua University news recently, Professor Tian Ling Ren Tsinghua University Institute of microelectronics in the "nature - Communication" (Nature Communications) published online entitled "full spectrum adjustable flexible graphene based field controlled light emitting devices" ("A spectrally tunable all-graphene-based flexible field-effect light-emitting device") study, revealed for the first time can light emitting device by a voltage control wavelength. Different from the traditional fixed wavelength LED and emission wavelength of this new device (in a single device) can be continuously adjustable between 750nm and 450nm, to break the existing display color synthesis method, is expected to have a revolutionary impact on the contemporary display, lighting and communication technology. Yale University and Tsinghua University postdoctoral Wang Xiaomu Micronanoelectronic PhD graduates Tian is the first author, Tsinghua University Micronanoelectronic Department Professor Tian Ling Ren is the corresponding author of the paper.

Spectrum of light emission wavelength regulated by gate voltage

Up to now, all the LED devices, the light-emitting color / wavelength are determined by light-emitting materials. For the existing LED, once the device is completed, the emission wavelength is fixed. Traditional display or lighting technology to adjust the number of fixed colors (typical devices using red, green, blue three primary colors) of the brightness of the unit, to achieve color or white light. This is the first report of the wavelength / color tunable LED, obtain excellent in color fidelity at the same time, also can make the number of light emitting unit display device is decreased significantly, thus greatly optimize the driving circuit and reduce power consumption, this achievement has far-reaching significance in related fields. "The work is expected to open up new research directions in the field of light-emitting devices," the reviewer said".

The mechanism of controlling the emission wavelength by gate voltage

Graphene has unique physical properties, and has been widely used in the controlled photonic / optoelectronic devices. However, due to the characteristics of zero band gap and non luminous recombination rate, the graphene based light-emitting devices are a difficult problem in the academic field. He became professor of innovative research group by laser direct writing technique, the half reduced srGO material in the reduction of graphene oxide and graphene interface. The material has high conductivity of graphene and wide band gap characteristics of graphene oxide. By constructing an in-plane gate structure, the gate voltage can be applied to modulate the Fermi level of srGO, so as to control the central wavelength of the LED emission in real time. The LED also has the characteristics of high brightness and can be made into flexible devices, is an ideal component of modern LED display, lighting and communication technology.

In recent years, research became devoted to graphene and other two-dimensional electronic devices, new devices with particular attention to break the traditional limit device, lay the foundation for a new generation of micro nano electronics, has received a number of innovations in the novel graphene based memory, acoustic devices and sensors and other aspects, such as transparent flexible graphite graphene headset and low-power graphene rram. The research results have been supported by the National Natural Science Foundation of china.