Endowing a single material with various types of luminescence, that is, exhibiting a simultaneous optical response to different stimuli, is vital in various fields. A photoluminescence (PL)‐ and mechanoluminescence (ML)‐based multifunctional sensing platform is built by combining heterojunctioned ZnS/CaZnOS:Mn²⁺ mechano‐photonic materials using a 3D‐printing technique and fiber spinning. ML‐active particles are embedded in micrometer‐sized cellulose fibers for flexible optical devices capable of emitting light driven by mechanical force. Individually modified 3D‐printed hard units that exhibit intense ML in response to mechanical deformation, such as impact and friction, are also fabricated. Importantly, they also allow low‐pressure sensing up to ≈100 bar, a range previously inaccessible by any other optical sensing technique. Moreover, the developed optical manometer based on the PL of the materials demonstrates a superior high‐pressure sensitivity of ≈6.20 nm GPa⁻¹. Using this sensing platform, four modes of temperature detection can be achieved: excitation‐band spectral shifts, emission‐band spectral shifts, bandwidth broadening, and lifetime shortening. This work supports the possibility of mass production of ML‐active mechanical and optoelectronic parts integrated with scientific and industrial tools and apparatus.

In the last few years, huge progress has been made in the development of remote optical thermometry strategies, due to their non-contact, high-sensitivity and fast measurement characteristics, which are especially important for various industrial and bio-applications. For these purposes, lanthanide-doped particles seem to be the most promising luminescence thermometers. In this study, Tm³⁺/Yb³⁺:Na₃GdV₂O₈ (NGVO) phosphors were prepared using a sol–gel method. Under 980 nm excitation, the upconversion (UC) and down-shifting (DS) emission spectra are composed of two visible emission bands arising from the Tm³⁺ transitions ¹G₄ → ³H₆ (475 nm) and ¹G₄ → ³F₄ (651 nm), a strong emission at 800 nm (³H₄ → ³H₆) in the first biological window and emission in the third biological window at 1625 nm (³F₄ → ³H₆), respectively. Accordingly, the luminescence intensity ratio (LIR) between the Tm³⁺ LIR₁ (800/475) and LIR₂ (1625/475) transitions demonstrates excellent relative sensing sensitivity values (4.2% K⁻¹–2% K⁻¹) and low-temperature uncertainties (0.4 K–0.5 K) over a wide temperature sensing range of 300 K to 565 K, which are remarkably better than those of many other luminescence thermometers. This phosphor exhibits strong NIR emission at low excitation density, meaning that it has potential uses in deep tissue imaging, optical signal amplification and other fields. The results indicate that Tm³⁺/Yb³⁺:NGVO is an ideal candidate for thermometers and particularly for biological applications.

Mechanoluminescence (ML) is a powerful phenomenon that enables light generation induced with mechanical or acoustic waves, and remote temperature sensing via luminescence thermometry techniques. In this work, the multi‐functional, ML‐active materials based on Er³⁺ and Mn²⁺ co‐doped ZnS/CaZnOS heterostructure are developed for remote temperature monitoring and visual sensing of force and sound. The material exhibits characteristic photoluminescence (PL) under UV and NIR (up‐conversion) excitation, with energy transfer from Er³⁺ to Mn²⁺ influencing the emission color. The effects of force‐to‐light conversion are studied in detail by measuring the ML intensity versus the applied power for Er³⁺ and Mn²⁺ emission in the single‐doped and co‐doped materials. Temperature‐dependent PL is utilized to calibrate luminescence thermometry response, with Er³⁺ thermally‐coupled levels and non‐thermally‐coupled levels of Er³⁺/Mn²⁺, providing temperature sensing capabilities. The unique combination of sound‐induced ML with luminescence thermometry allowed optical temperature detection, alike during the drilling process, and in the externally heated system, using pulsed sonications. Whereas, applying continuous excitation, the sound‐to‐heat conversion is studied and visualized using the developed ML‐based optical thermometers. This approach demonstrates the excellent application potential of sound‐to‐light conversion for remote monitoring and, more importantly, for excitation‐light‐free temperature probing of different systems and working devices.

Nonlinear optical materials are essential in areas such as nanophotonics, optical information processing, and biomedical imaging. However, nanomaterials employed for these diverse applications to date are efficient only for one type of nonlinear optical activity. Herein, the first multimodal nonlinear optically active class of nanomaterials based on lanthanide‐doped lithium niobate nanoparticles, which simultaneously exhibit unprecedentedly efficient second and third harmonic generation, as well as up‐conversion photoluminescence, is reported. These dielectric nanoparticles retain their high nonlinear optical conversion efficiency both as powder and as aqueous colloidal solution. The high stability also allows for the fabrication of optically active biocompatible micron‐sized fibers and polymer‐based 3D‐printable objects, as well as for fingerprint detection. Finally, the first 8‐bit coding platform purely based on multimodal nonlinear optical activity originating from different parametric and nonparametric processes is demonstrated, showcasing the technological potential of these materials for both anti‐counterfeiting and advanced optical information processing.

Distinct types of luminescence that are activated by various stimuli in a single material offer exciting developmental opportunities for functional materials. A versatile sensing platform that exhibits photoluminescence (PL), persistent luminescence (PersL), and mechanoluminescence (ML) is introduced, which enables the sensitive detection of temperature, pressure, and force/stress. The developed Sr₂MgSi₂O₇:Eu²⁺/Dy³⁺ material exhibits a linear relationship between ML intensity and force and can be used as an ML stress sensor. Additionally, the bandwidth of the PL emission band and the PL lifetime of this material are remarkably sensitive to temperature, with values of ≈0.05 nm K⁻¹ and 1.29%/K, respectively. This study demonstrates PersL pressure sensing for the first time, using long‐lasting (seconds) lifetime as a manometric parameter. The developed material functions as an exceptionally sensitive triple‐mode visual pressure sensor; specifically, it exhibits: i) a sensitivity of ≈−297.4 cm GPa⁻¹ (8.11 nm GPa⁻¹) in bandshift mode, ii) a sensitivity of ≈272.7 cm⁻¹/GPa (14.8 nm GPa⁻¹) in bandwidth mode, and iii) a sensitivity of 42%GPa⁻¹ in PL‐lifetime mode, which is the highest value reported to date. Notably, anti‐counterfeiting, night‐vision safety‐sign, 8‐bit optical‐coding, and QR‐code applications that exhibit intense PersL are demonstrated by 3D‐printing the studied material in combination with a polymer.