Traditional sensing materials are often limited to the detection of a single physical quantity, while complex environmental scenarios often require multi parameter synchronous monitoring. Recently, a groundbreaking study by the City College of Zhejiang University designed a new luminescent material Sr ₂ MgSi ₂ O ₇: Eu ² ⁺/Dy ³ ⁺ (SMSO) has successfully achieved triple response of photoluminescence (PL), stress luminescence (ML), and long afterglow luminescence (PersL). PersL has been used for pressure sensing for the first time, and a programmable optical coding platform has been developed using 3D printing technology, bringing innovation to the fields of intelligent sensing and anti-counterfeiting!  

一、 Material core innovation: the third mock examination cooperation, breakthrough performance bottleneck

1. Stress sensing: linear response, wide dynamic range

Within the mechanical range of 3~30 N, the ML strength exhibits a linear relationship with external forces, attributed to the synergistic effect of oxygen vacancies and Dy ³ ⁺/Dy ² ⁺ trap states in the material. This characteristic makes it suitable for stress monitoring and early warning, intelligent structural health monitoring, and other fields.

2. Pressure Sensing: From "Transient Stress Sensing" to "Continuous High Pressure Sensing"

Traditional stress-induced luminescent materials (such as sulfides) rely on instantaneous mechanical stimulation to emit light, while SMSO materials, through trap level regulation, not only generate ML signals under pressure stimulation, but also achieve second level continuous luminescence through PersL. For the first time, PersL lifetime has been used as a pressure sensing parameter. Experiments have shown that its pressure sensitivity is as high as 42% GPa ⁻¹ (PL lifetime mode), far exceeding existing reports.

3. Temperature sensing: nanometer level precision response

The PL spectral bandwidth (FWHM) and lifetime of SMSO are extremely sensitive to temperature changes: 1) FWHM sensitivity: 0.05 nm/K, capable of detecting small temperature fluctuations; 2) PL lifetime sensitivity: 1.29%/K, suitable for a wide temperature range (-50~300 ℃). This dual parameter response mechanism is achieved through crystal field effects and carrier transition path control, providing a new solution for high-precision non-contact temperature measurement.

Source: Sensor Expert Network