Tian-Ling Ren’s group reported an intelligent artificial throat based on laser induced graphene

On February 24，Professor Tian-Ling Ren’s group at the Institute of Microelectronics, Tsinghua University, published a research article entitled " An Intelligent Artificial Throat with Sound-Sensing Ability Based on Laser Induced Graphene " in Nature Communications. The intelligent device has the characteristics of the integration of sound generating and detecting. It can both emit and detect sound in a single device and has excellent biocompatibility. Besides it can help the deaf-mute “speak” by attaching to the larynx. The device is a new application of graphene in the field of wearable electronics, and is expected to have a significant impact in biology, speech recognition and other fields.

Schematic diagram of the intelligent artificial throat. The meaningless hums in the throat can be recognized and converted into controllable sound.

Acoustic devices mainly include sound sources and sound detectors. It is important to the functional integration of generating and detecting sound in a single device and apply them to the wearable field. The traditional sound sources and sound detectors which work in the audible domain (20Hz - 20kHz) are usually discrete devices and single device can’t achieve both sound generating and detecting. In addition, the traditional acoustic devices don’t have flexibility, it is not suitable for wearable applications. On the other hand, flexible displays, sensors have been a great breakthrough. It is necessary to study the integrated flexible acoustic devices in order to achieve a completely flexible electronic system.

Professor Ren's group proposed an integrated acoustic device that can generate and detect sound in a single device. It can generate sound based on the thermoacoustic effect of graphene and detect the sound based on piezoresistive effect. A low-cost laser direct writing technology is adopted to convert polyimide into large-scale patterned porous graphene. The porous graphene has high thermal conductivity and low heat capacity, so it can emit sound with the frequency of 100 Hz-40 kHz by thermoacoustic effect. Besides, the porous structure is extremely sensitive to the pressure and can recognize the weak vibration on the throat, resulting in the sound detection by piezoresistive effect. Therefore, the device can be used to detect the meaningless hums of the deaf-mute and this meaningless sound can be converted into precise sound with controllable frequency and intensity, so that it can help the deaf-mute “speak”.

In recent years, Prof. Ren contributes to the basic research and practical application of graphene devices, particularly focuses on the new micro-nano electronic devices which can break through the bottleneck of traditional devices. His research includes flexible graphene sound sources (published in ACS Nano and IEDM), graphene resistive memory (published in Nano Letters and Advanced Materials), tunable graphene LED (published in Nature Communications), graphene synaptic devices (published in Nano Letters), tunable graphene strain sensors (published in IEDM) and so on.

Lu-Qi Tao and He Tian (Ph.D. student in Ren’s group) are the co-first authors. Prof. Tian-Ling Ren and Prof. Yi Yang are the corresponding author of this work. This research was funded by the National Natural Science Foundation of China and the Ministry of Science and Technology of China.