Manipulating Electroluminochromism Behavior of Viologen‐Substituted Iridium(III) Complexes through Ligand Engineering for Information Display and Encryption

Abstract

Electrically controlling photoluminescence has attracted great research interest and offers many opportunities for technological developments. Electroluminochromic materials undergo redox reactions under low‐voltage stimuli to achieve reversible luminescence switching. Till now, photoluminescence switching of a single molecule caused by electrical stimuli is restricted to intensity response because the redox‐active moieties are good electron donors or acceptors and electrical stimuli can regulate the photoinduced electron‐transfer and affect the luminescence intensity. In this work, the manipulation of the electroluminochromism behavior of a series of viologen‐substituted iridium(III) complexes through the regulation of ligand orbital energy levels and electronic communication between the viologen pendants and the iridium(III) complex core is reported. Electrochemical redox reactions reversibly modulate either the luminescence quenching effect or the push–pull electronic effect of the viologen substituents, achieving multicolor “on–off” luminescence response toward electrical stimuli and luminescence manipulation between two emissive states with different wavelengths and lifetimes. To illustrate the promising applications of these electroluminochromic materials, recording and displaying luminescence information under electrical stimuli are demonstrated. Information encryption is realized by letting the electroluminochromism occur in the near‐infrared region or in the time domain. Near‐infrared camera or time‐resolved luminescence analysis can be used to help read the invisible information.

Tunable Thermoresponsive Flexible Films for Adaptive Temperature Management and Visual Temperature Monitoring

“…Switchable optical properties are important for numerous frontier fields including communication, camouflage, encryption, and imaging/sensing. − To demonstrate the thermo-stimuli switchable optical properties of the PCM@PDMS, the change between transparent and opaque states of the prepared C 20 @PDMS was investigated under a heating stage (60 °C). As shown in Figure a, the initial C 20 @PDMS was opaque at ∼25 °C because of the light scattering induced by the solid PCM embedded in PDMS.…”

C3-Symmetric Propeller-like Phenanthridine Derivative with Multiple Write-In Modes for Programmable Anti-Counterfeiting

“…have drawn tremendous attention in materials science and chemistry. SRCMs have shown huge potentials in display, 10 sensors, 17,18 bioimaging, 20,21 rewritable paper, 14,15 data encryption, 8,19 and anticounterfeiting. 5,9,22,23 However, the existing SRMCs systems suffer from the following drawbacks.…”

“…have drawn tremendous attention in materials science and chemistry. SRCMs have shown huge potentials in display, sensors, , bioimaging, , rewritable paper, , data encryption, , and anti-counterfeiting. ,,, However, the existing SRMCs systems suffer from the following drawbacks. First, a lot of SRCMs generally only respond to one stimulus, leading to monotonic outputs and limited applications.…”

“…1−3 These visual signals triggered by the stimulus can be directly discerned with naked eyes, offering a simple and straightforward approach for information collection. Inspired by this, stimuli-responsive chromic materials (SRCMs) presenting variable appearances or emission colors in response to various external stimuli (e.g., light, 4−6 heat, 7−9 electricity, 10 pH, 11−13 humidity, 14,15 mechanical force, 16,17 environmental polarity and rigidity, 18,19 etc.) have drawn tremendous attention in materials science and chemistry.…”

Recyclable photoluminescent composites via incorporating ZnS‐based phosphors into dynamic crosslinking elastomeric matrixes

“…A series of platinum(II) and iridium(III) complexes were systematically designed and precisely synthesized through organic chemical reactions. [15][16][17][18][19] Based on metal-to-ligand, ligand-toligand or intra-ligand charge transfer, [20] corresponding single molecules, oligomers and polymers consisted of platinum(II) and iridium(III) complexes expressed tunable luminescent properties, for example, intense photoluminescence (PL) after external excitation. [21] Apart from organic luminescent materials, inorganic luminophores were obtained by feasible ceramic powder sintering and element doping.…”