Persistent- and Mechanoluminescence of Er-Doped NaYF for Multipurpose Use.

Advanced functional materials that possess both persistent luminescence (PersL) and mechanoluminescence (ML) have gained considerable attention during the past few years owing to their potential applications in many fields such as two-dimensional stress sensing, energy-saving lighting, and optical bioimaging. However, combined investigation of PersL and ML is still in its infancy. Here, the optical property of Er-doped NaYF, mainly focusing on the PersL and ML characteristic and their correlation, is studied in detail.

2D Perovskite Heterojunction-Based Self-Powered Polarized Photodetectors with Controllable Polarization Ratio Enabled by Ferro-Pyro-Phototronic Effect.

Metal halide perovskites (MHPs) are commonly used in polarization-sensitive photodetectors (PDs) for applications such as polarization imaging, remote sensing, and optical communication. Although various methods exist to adjust the polarization-sensitive photocurrent, a universal and effective approach for continuous control of MHPs' optoelectronic and polarized properties is lacking. A universal strategy to electrically modulate the polarization ratio (PR) of self-powered polarized PDs using the ferro-pyro-phototronic effect (FPPE) in 2D perovskites is presented.

Force-Induced Ultraviolet C Luminescence of Pr-Doped SrPO for X-Ray Dosimetry.

Mechanoluminescent materials have broad application prospects in advanced displays, stress imaging, and anti-counterfeiting owing to their ability to convert mechanical stimuli into light. However, most previous studies have focused on the visible and near-infrared regions. Although natural ultraviolet C (UVC) light is nearly absent on the Earth's surface, it plays an important role in many fields.

Synergistic Effect of Ionic Liquid and Embedded QDs on 2D Ferroelectric Perovskite Films with Narrow Phase Distribution for Self-Powered and Broad-Band Photodetectors.

2D layered metal halide perovskites (MHPs) are a potential material for fabricating self-powered photodetectors (PDs). Nevertheless, 2D MHPs produced via solution techniques frequently exhibit multiple quantum wells, leading to notable degradation in the device performance. Besides, the wide band gap in 2D perovskites limits their potential for broad-band photodetection.

Surface Passivation to Enhance the Interfacial Pyro-Phototronic Effect for Self-Powered Photodetection Based on Perovskite Single Crystals.

The interfacial pyro-phototronic effect (IPPE) presents a novel approach for improving the performance of self-powered photodetectors (PDs) based on metal halide perovskites (MHPs). The interfacial contact conditions within the Schottky junctions are crucial in facilitating the IPPE phenomenon. However, the fabrication of an ideal Schottky junction utilizing MHPs is a challenging endeavor.

Mechanical force induced luminescence ratiometric thermometry in CaZnOS:Dy.

The I-H and F-H transitions of Dy are usually used for luminescent ratiometric thermometry in the form of photoluminescence. However, here we demonstrate the possibility of using this pair of lines for luminescent ratiometric thermometry in the model of mechanoluminescence (ML) in CaZnOS:Dy. Upon stimulation of an external mechanical force rather than light, CaZnOS:Dy emits bright yellow luminescence.

A high-precision thermometry strategy by replacing the infrared with visible light for detection.

We have developed a high-precision thermometry strategy based on I-I (I) and S-I (I) transitions of Er, after replacing the measurement of the I-I (I) transition with the S-I transition, i.e., using visible light for detection instead of infrared.

Mechanically induced photons from ultraviolet-C to near-infrared in Tm-doped MgF.

Mechanoluminescence (ML) plays a vital role in various fields, and has gained increasing popularity over the past two decades. The widely studied materials that are capable of generating ML can be classified into two groups, self-powered and trap-controlled. Here, we demonstrate that both self-powered ML and trap-controlled ML can be achieved simultaneously in MgF:Tm.

Mechanoluminescence ratiometric thermometry via MgF:Tb.

Mechanoluminescent materials have attracted considerable attention over the past two decades, owing to the ability to convert external mechanical stimuli into useful photons. Here we present a new, to the best of our knowledge, type of mechanoluminescent material, i.e.

Ratiometric optical thermometry based on upconversion luminescence with different multi-photon processes in CaWO:Tm/Yb phosphor.

Ratiometric optical thermometry based on upconversion (UC) luminescence with different multi-photon processes in CaWO:Tm,Yb phosphor was developed. A new fluorescence intensity ratio (FIR) thermometry, utilizing the ratio of the cube of F emission to the square of G emission of Tm and retaining the feature of anti-interference of excitation light source fluctuations, is proposed. Under the hypotheses of the UC terms being neglected in the rate equations and the ratio of the cube of H emission to the square of G emission of Tm being a constant in a relatively narrow temperature range, the new FIR thermometry is valid.

Ultra-sensitive luminescence ratiometric thermometry from E→A transitions of AlTaO:Cr.

In recent years, non-contact ratiometric luminescence thermometry has continued to gain popularity among researchers, owing to its compelling features, such as high accuracy, fast response, and convenience. The development of novel optical thermometry with ultrahigh relative sensitivity (Sr) and temperature resolution has become a frontier topic. In this work, we present a novel, to the best of our knowldege, luminescence intensity ratio (LIR) thermometry method that relies on AlTaO:Cr materials, based on the fact that they possess both anti-Stokes phonon sideband emission and R-line emission at the E→A transitions and have been confirmed to follow the Boltzmann distribution.

Tb-based multi-mode optical ratiometric thermometry.

Owing to some special superiority, luminescence ratiometric thermometry, mainly including dual excitations single emission and single excitation dual emissions, has gained popularity over the past few years. However, developing novel ratiometric thermometry that can work in multi-mode is still a challenge. Here we report a temperature measurement method based on the photoinduced luminescence of Tb in the low-cost and easy to prepare calcium tungstate.

MgF:Mn: novel material with mechanically-induced luminescence.

Mechanoluminescent (ML) materials can directly convert external mechanical stimulation into light without the need for excitation from other forms of energy, such as light or electricity. This alluring characteristic makes ML materials potentially applicable in a wide range of areas, including dynamic imaging of force, advanced displays, information code, storage, and anti-counterfeiting encryption. However, current reproducible ML materials are restricted to sulfide- and oxide-based materials.

Persistent visible luminescence of SrF:Pr for ratiometric thermometry.

Luminescence-based thermometry, especially the ratiometric temperature sensing technology, has attracted considerable attention recently due to its characteristics such as non-contact operating mode and strong capacity of resisting disturbance. Differing from the conventional strategy that usually needs continuous excitation, here an optical thermometry, which we have named the persistent luminescence intensity ratio (PLIR) thermometry, is proposed. The PLIR thermometry relies on the optical material SrF:Pr that could emit luminescence for several hours and even longer after being charged by X-ray.

Visible-to-ultraviolet-C upconverted photon for multifunction via CaSiO:Pr.

The ultraviolet C (UVC) photon plays a key role in a broad spectrum of fields. With the implementation of the Minamata Convention, searching for a new way to achieve UVC light is highly desired. Here we develop a material of CaSiO:Pr that can emit UVC light upon excitation of a 450-nm laser or even a very cheap 450-nm LED, a fact confirmed by using a solar blind camera to capture UVC emission from CaSiO:Pr.

Luminescence properties, energy transfer and thermal stability of white emitting phosphor Sr(PO):Ce/Tb/Mn for white LEDs.

A series of Sr(PO):Ce/Mn/Tb phosphors were synthesized by a high temperature solid phase method. After introducing Ce as sensitizer in Sr(PO):Ce/Mn, the efficient energy transfer from Ce to Mn was observed and analyzed in detail, and Sr(PO):Ce/Mn was demonstrated to be color tunable, changing from blue to orange red. In addition, Tb ion, which mainly emits green light, was further added into the Sr(PO):Ce/Mn.

Boltzmann-distribution-dominated persistent luminescence ratiometric thermometry in NaYF:Pr.

A novel, to the best of our knowledge, optical temperature measurement method is proposed, i.e., persistent luminescence intensity ratio (PLIR) thermometry.

Mechanism of the trivalent lanthanides' persistent luminescence in wide bandgap materials.

The trivalent lanthanides have been broadly utilized as emitting centers in persistent luminescence (PersL) materials due to their wide emitting spectral range, which thus attract considerable attention over decades. However, the origin of the trivalent lanthanides' PersL is still an open question, hindering the development of excellent PersL phosphors and their broad applications. Here, the PersL of 12 kinds of the trivalent lanthanides with the exception of La, Lu, and Pm is reported, and a mechanism of the PersL of the trivalent lanthanides in wide bandgap hosts is proposed.

Eu-based dual-excitation single-emission luminescent ratiometric thermometry.

Recently, single-band ratiometric (SBR) thermometry becomes a hot-spot in the research field of optical thermometry. Here we propose a new SBR thermometry by combining the temperature-induced red shift of charge transfer state (CTS) of W-O and Eu-O with the ground state absorption (GSA) and excited state absorption (ESA) of Eu. The emitting intensity of the D-F transition of Eu is monitored under CTS, GSA and ESA excitations at different temperatures.

High performance FIR thermometry on the basis of the redshift of CTB by dual-wavelength alternative excitation in Eu:YVO.

Compared with the forbidden 4f transition of rare earth ions, the strong absorption of the charge transfer band (CTB) enabled fluorescence thermometry to have high luminescence efficiency. Based on the temperature induced redshift of CTB, a high performance fluorescence intensity ratio (FIR) thermometry performed by dual-wavelength alternative excitation was studied. By way of the rising and falling edges of CTB in doped , monochrome sensitivity as a function of excitation wavelength was studied in the range of 303-783 K.

Stably and highly sensitive FIR thermometry over a wide temperature range of 303-753 K based on the GdVO:Eu and AlO:Cr hybrid particles.

Fluorescence intensity ratio (FIR) temperature sensors provide an effective method to control or study fine variations in physical and biological research because of their high sensitivity, accuracy, and spatial resolution. However, it is difficult to maintain high sensitivity over a wide temperature range using FIR temperature sensors because of the limits of the Boltzmann distribution law. In this study, sensitivity amplification for a wide temperature range in FIR thermometry based on GdVO:Eu and AlO:Cr hybrid particles is achieved.

Eu-based luminescence ratiometric thermometry.

Recently, luminescence ratiometric thermometry has gained ever-increasing attention due to its merits of rapid response, non-invasiveness, high spatial resolution, and so forth. For research fields relying on temperature measurements, achieving a higher relative sensitivity of this measurement is still an important task. In this work, we developed a strategy for achieving a more sensitive temperature measurement, one merely depending on the photoluminescence of Eu.

On the Er NIR photoluminescence at 800 nm.

Here, we study the Er NIR I-I photoluminescence peaking at 800 nm. It can be detected with a good signal-to-noise for the prepared CaWO:Yb,Er phosphors upon excitation at 980 nm. When directly exciting the Er green and red emitting states over the 333-773 K temperature range, the 800 nm photoluminescence for the samples is undetectable.

Origin of the giant thermal enhancement of the Er ion's I-I photoluminescence.

The Er ion's I-I emission spectrum, which was rarely reported before, was successfully observed in the as-prepared scheelite-structured CaWO:Yb,Er phosphors, upon excitation at 980 nm. This photoluminescence, peaking at ca. 800 nm, was found to undergo a monotonous and giant enhancement with increasing the temperature from 333 to 813 K.