Thermally induced multicolor emissions of upconversion hybrids with large color shifts for anticounterfeiting applications

Abstract

By utilizing opposite luminescence temperature-dependences between lanthanide-doped microrods and nanocrystals, upconversion hybrids with color-tunable emissions are developed for more secure anticounterfeiting applications.

Excitation dependent visible and NIR photoluminescence properties of Er3+, Yb3+ co-doped NaBi(MoO4)2 nanomaterials

“…1,2 Due to these exceptional luminescence properties, lanthanide doped nanomaterials have applications in various elds such as sensing, photocatalysis, solar cells, bio-imaging, therapy, diagnostics, anti-counterfeiting, latent ngerprint development, optical ampliers, solid state lighting, etc. [1][2][3][4][5][6][7][8] Among lanthanide ions, the trivalent erbium ion shows emission in the visible and NIR regions and also exhibits upconversion luminescence properties. However, its upconversion luminescence properties are very poor if it is doped alone due to low absorption cross section.…”

Combinations of Superior Inorganic Phosphors for Level‐Tunable Information Hiding and Encoding

“…Emission colors also show a red‐shift phenomenon by increasing irradiation time and power density. [ 254 ] For the designed patterns that are excited by an 808 nm laser, they would be stimulated by the 980 nm laser since the Yb 3+ is an indispensable part for its bridge‐functional role between the Nd 3+ (response to the 808 nm laser) and activators. In Figure 11c, UCNPs containing long‐lived and short‐lived emissions originating from the Mn 2+ and Ln 3+ exhibit bright future in practical applications.…”

Precision tuning of rare-earth-doped upconversion nanoparticles via droplet-based microfluidic screening

“…15 Standout applications of UCNPs include biological imaging and therapy, 16 photonic devices, 17 luminescence thermometry, 18 biosensing, 19 and anti-counterfeiting. [20][21][22] Regarding white light emission, it is possible to tune rare-earth UCNPs to act as single entity white light emitters, overcoming the previously noted problems encountered in heterogeneous populations. For example, Sivakumar et al demonstrated a white light thin film made from RE 3+ -doped LaF 3 nanoparticles, which could be excited using a single NIR source.…”