The way of university lies in Mingde. As a landmark building of the University of Chinese Academy of Sciences (UCAS), Mingde Bell Tower occupies a unique position in the hearts of teachers and students of UCAS. As an external stimulus, the sound of the bell conveys a wealth of information to humans after being collected by the human ear. The three elements of sound include loudness, pitch and timbre. Loudness refers to the size of the sound, which is related to the amplitude of the sounding body; pitch refers to the height of the sound, which is related to the frequency of the sounding body; timbre is the uniqueness of the sound, which is related to the sounding body. related to the waveform. Therefore, accurate recognition of sound is of great significance for the transmission of information.

In the era of artificial intelligence, optoelectronic synapses are used to learn, calculate and remember information, promoting the development of future bionic electronic devices and humanoid robots. Researchers have built a number of synaptic devices for sound recognition. However, a synaptic device capable of simultaneously recognizing the loudness, pitch, and timbre of a sound for precise sound perception has not yet been realized.

In recent years, the research group of Professor Huang Hui from the University of Chinese Academy of Sciences has carried out research on organic optoelectronic synapses, developed its applications in image recognition, artificial vision systems, etc., and achieved a series of important scientific research results, which have been published in high-level academic journals at home and abroad. Journal (J. Am. Chem. Soc., 2023, DOI: 10.1021/jacs.2c13471. Angew. Chem. Int. Edit. 2023, 62, e202213733. Adv. Opt. Mater. 2022, 10, 2201104. Cell Rep. Phys. Sci. 2021, 2, 100507.). Recently, based on the three elements of sound, the research group prepared an organic optoelectronic synaptic device that can recognize the loudness, pitch, and timbre of sound at the same time, and recognized the bells of the Mingde Bell Tower of the University of Science and Technology of China. Related work was published in Nano- On Micro Letters.

Figure：Basic properties of materials, device performance and sound recognition of the bell tower of UCAS

In this paper, a new acceptor material (BSC8-4F) was designed, and after matching with a known donor material (PM6), an organic photoelectric synaptic device with ITO/PEDOT:PSS/D:A/PDINN/AG was prepared. By changing the voltage, frequency, and light intensity of the input of the device, the magnitude of the postsynaptic current of the output signal, the frequency of synaptic signal change and the waveform of the synaptic signal are adjusted respectively, so as to correspond to the amplitude, frequency, and waveform of the sound, and further adjust the loudness, tone, and timbre of the sound. The identification factor is proposed to establish the quantitative relationship between voltage, frequency, light intensity and postsynaptic current, so as to achieve the purpose of sound recognition. Finally, the recognition of the bell tower bell of the National University of Science and Technology was realized, and the accuracy rate was as high as 99.8%.

The first author of the paper is Dr. Wei Yanan, Assistant Special Research of UCAS, and the corresponding authors are Professor Huang Hui and Assistant Professor Zhang Xin.

Thanks to the key research and development program of the Ministry of Science and Technology, the National Natural Science Foundation of China and the relevant projects of the Academy of Sciences.

Links：Wei, Y., Liu, Y., Lin, Q. et al. Organic Optoelectronic Synapses for Sound Perception. Nano-Micro Lett. 15, 133 (2023). https://doi.org/10.1007/s40820-023-01116-3