Controllable Modulation of Efficient Phosphorescence Through Dynamic Metal‐Ligand Coordination for Reversible Anti‐Counterfeiting Printing of Thermal Development

Abstract

Dynamically tunable room-temperature phosphorescence (RTP) organic materials have attracted considerable attention in recent years due to their great potential over a wide variety of advanced applications. However, the precise regulation of the intersystem crossing (ISC) process for efficient RTP materials with dynamically modulated properties in a rigid environment is challenging. Herein, an effective strategy for RTP material preparation with controllably regulated properties is developed via the construction of dynamic metal-ligand coordination in a host-guest doped system. The coordination interaction promotes ISC and phosphorescence emission of the guest, thus allowing the modulation of the photophysical properties of doped materials by changing the doping ratio and Zn 2+ counterions. By taking advantage of the reversible metal-ligand coordination interaction, the coordination-activated, and dissociation-deactivated RTP is dynamically manipulated. With the unique Zn 2+ -responsible RTP enhancement materials, the anti-counterfeiting applications of thermal development, and color inversion have been constructed for inkjet printing of high-resolution patterns with high reversibility for many write/erase cycles. The results show that dynamic metal-ligand coordination strategy is a promising approach for achieving efficient RTP materials with controllably modulated properties.

Stimulus-Responsive Organic Phosphorescence Materials Based on Small Molecular Host–Guest Doped Systems

“…The introduction of metal ions into the host–guest doped system to form coordination interactions with guest molecules is an effective strategy to modulate the phosphorescence properties of the doped materials due to the promoted SOC of organic luminophore ligands coordinated with metal ions . Recently, Dong et al proposed an effective strategy that introduced dynamic metal–ligand coordination into host–guest doped systems, which enabled the preparation of RTP material with regulated properties . A quinoline derivative with bipyridine structure (DPPQ) and phenoxathiine (PXT) were developed as guest and host, respectively (Figure b).…”

“…/ S Total ratios versus the number of cycles for PXT/DPPQ doped materials with addition of ZnCl 2 and TBAF. Reproduced with permission from ref . Copyright 2022 John Wiley and Sons.…”

“…90 Recently, Dong et al proposed an effective strategy that introduced dynamic metal− ligand coordination into host−guest doped systems, which enabled the preparation of RTP material with regulated properties. 91 A quinoline derivative with bipyridine structure (DPPQ) and phenoxathiine (PXT) were developed as guest and host, respectively (Figure 10b). Furthermore, the stable d 10 electronic configuration led earth-abundant zinc salts to be selected as the coordination units.…”

Organic Host‐Guest Materials with Bright Red Room‐Temperature Phosphorescence for Persistent Bioimaging†

“…Organic room‐temperature phosphorescence (RTP) materials have attracted immense attention due to their peculiar photophysical process and potential applications in advanced printable and writable security inks, [ 1‐4 ] high‐resolution bioimaging, [ 5‐7 ] microenvironment oxygen visual sensing and quantitative detection. [ 8‐11 ] Several attempts have been made to develop high‐performance RTP materials, including the introduction of heavy atoms or halogen/hydrogen bonding, [ 12‐17 ] doping in a rigid matrix, [ 18‐26 ] construction of metal‐organic frameworks, [ 27‐28 ] and ionic‐π interactions. [ 29‐31 ] However, limited RTP materials with long emission wavelengths are reported due to the lack of a preparation strategy.…”

Time‐dependent Phosphorescence Color of Carbon Dots in Binary Salt Matrices through Activations by Structural Confinement and Defects for Dynamic Information Encryption

“…Importantly, yellow RTP is emitted earlier than green RTP, providing powerful evidence that structural defects of inorganic matrices have a much weaker binding force to excitons than structural confinement. With the help of the excitation wavelength‐dependent TDCP performance, the CDs/Na 0.5 Mg 0.25 Cl can be used for multi‐level dynamic phosphorescence color 3D coding to achieve advanced dynamic information encryption [34–41] . This proposed strategy can not only give new life to old luminescent materials but also open up a new avenue for the design and application of time‐dependent dynamic luminescent materials.…”