This is the first comprehensive review on methods and materials for use in optical sensing of
pH values and on applications of such sensors. The Review starts with an introduction that …

Inner filter effect (IFE) was previously considered as an error in fluorescence measurement.
In recent years, it has been developed as an important non-irradiation energy conversion …

Upconversion is a nonlinear optical phenomenon that involves the emission of high‐energy
photons by sequential absorption of two or more low‐energy excitation photons. Due to their …

Luminescence-based techniques continue to attract considerable attention due not only to
their current range of applications but also to their wide potential in the fields of optical …

Lanthanides refer to the 15 elements located at the sixth period and IIIB group in the periodic
table, ranging from lanthanum to lutetium, with the electronic configuration of [Xe] 4f n–1 5d …

Theranostics is a concept of integrating imaging and therapy into a single platform for use in
the next generation of personalized medicine to meet the challenges in modern health …

Temperature sensors play a significant role in biology, chemistry, and engineering,
especially those that can work accurately in a noninvasive manner. We adopted a …

Significant progress on upconversion‐nanoparticle (UCNP)‐based probes is witnessed in
recent years. Compared with traditional fluorescent probes (eg, organic dyes, metal …

Photon-upconverting nanoparticles (UCNPs) can be excited by near-infrared light and emit
visible light (anti-Stokes emission) which prevents autofluorescence and light scattering of …

Upconversion (UC) refers to nonlinear optical processes in which the sequential absorption
of two or more photons leads to the emission of light at shorter wavelength than the …