With the rapid development of artificial intelligence and human-computer interaction technologies, tactile sensing technology, as a key tool for converting mechanical stimuli into readable signals, has garnered widespread attention. However, most mainstream tactile sensing technologies currently rely on the triboelectric effect. While they offer advantages such as self-powering and high sensitivity, they are highly susceptible to interference from environmental humidity, dust, and other factors, leading to significant reductions in reliability and durability in complex practical applications. Additionally, although existing mechanoluminescent materials can emit light through mechanical stress, most primarily emit visible light, requiring expensive specialized detectors and necessitating use in dark environments, which limits their practical applications.

Recently, Associate Professor Suo Hao from Hebei University, along with Professor Feng Wang and Dr. Xin Zhang from City University of Hong Kong, proposed a novel self-powered tactile sensing platform. This platform utilizes piezoelectric materials to achieve mechanical-electro-optical conversion, effectively overcoming environmental interference issues. The research team developed a new class of ScBO₃:Cr³⁺ crystals capable of generating strong broadband near-infrared light through self-recovering mechanical luminescence under a single mechanical pressure. By employing a combined doping strategy, they achieved precise control over the emission spectrum across a wide wavelength range. Using standard silicon photodiodes for efficient photoelectric conversion, they ultimately constructed a tactile pen with fast response and low threshold, which can accurately authenticate signatures even in complex lighting and humidity conditions with the aid of machine learning algorithms. The related paper, titled "A Self-Powered Tactile Sensor Resistant to Environmental Interference," was published in Advanced Materials.

The working principles and performance differences of three tactile sensing systems were compared. Traditional triboelectric tactile sensors experience significant performance degradation in high-humidity environments, as moisture infiltration leads to charge neutralization and dissipation. While the visible light mechano-luminescence sensing system can achieve optical imaging and electronic sensing, it relies on expensive visible light detectors and requires operation in dark environments to avoid interference from ambient light. In contrast, the system proposed in this study employs piezoelectric near-infrared mechano-luminescence as the conversion medium, paired with low-cost silicon photodiodes, which not only boasts high photoelectric conversion efficiency but also exhibits strong resistance to ambient light and humidity interference.

Source: Sensor Expert Network