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Mechanoluminescent (ML) materials, which have the ability to convert mechanical energy to optical energy, have found huge promising applications such as in stress imaging and anti-counterfeiting. However, the main reported ML phosphors are based on trap-related ones, thus hindering the practical applications due to the requirement of complex light pre-irradiation process. Here, a self-recoverable near infrared (NIR) ML material of LaAl1-xO3: xCr3+ (x=0.2 ​%, 0.4 ​%, 0.6 ​%, 0.8 ​%, 1.0 ​%, and 1.2 ​%) has been developed. Based on the preheating method and corresponding ML performance analysis, the influences of residual carriers are eliminated and the detailed dynamic luminescence process analysis is realized. Systematic experiments are conducted to reveal the origin of the ML emissions, demonstrating that ML is dictated more by the non-centrosymmetric piezoelectric crystal characteristic. In general, this work has provided significant references for exploring more efficient NIR ML materials, which may provide potential applications in anti-counterfeiting and bio-stress sensing.

Optical temperature sensors, which can accurately detect temperature in biological systems, are crucial to the development of healthcare monitoring. To challenge the state-of-art technology, it is necessary to design single luminescence center doped materials with multi-wavelength emission for optical temperature sensors with more modes and higher resolution. Here, an Er3+ single-doped KYF4 nanocrystals glass ceramic with an obvious thermochromic phenomenon is reported for the first time, which shows a different temperature-dependent green, red, and near-infrared luminescence behavior based on thermal disturbance model. In addition, Er3+ single-doped GC fiber was drawn and fabricated into multi-mode optical fiber temperature sensor, which has superior measured temperature resolution (＜0.5 ​°C), excellent detection limit (0.077 ​°C), and high correlation coefficient (R2) of 0.99997. More importantly, this sensor can monitor temperature in different scenarios with great environmental interference resistance and repeatability. These results indicate that our sensor shows great promise as a technology for environmental and healthcare monitoring, and it provides a route for the design of optical fiber temperature sensors with multi-mode and high resolution.

Mechanoluminescent (ML) materials, which have the ability to convert mechanical energy to optical energy, have found huge promising applications such as in stress imaging and anti-counterfeiting. However, the main reported ML phosphors are based on trap-related ones, thus hindering the practical applications due to the requirement of complex light pre-irradiation process. Here, a self-recoverable near infrared (NIR) ML material of LaAl1-xO3: xCr3+ (x = 0.2 %, 0.4 %, 0.6 %, 0.8 %, 1.0 %, and 1.2 %) has been developed. Based on the preheating method and corresponding ML performance analysis, the influences of residual carriers are eliminated and the detailed dynamic luminescence process analysis is realized. Systematic experiments are conducted to reveal the origin of the ML emissions, demonstrating that ML is dictated more by the non-centrosymmetric piezoelectric crystal characteristic. In general, this work has provided significant references for exploring more efficient NIR ML materials, which may provide potential applications in anti-counterfeiting and bio-stress sensing. [ABSTRACT FROM AUTHOR]