On-demand modulating afterglow color of water-soluble polymers through phosphorescence FRET for multicolor security printing

Abstract

Developing full-color organic ultralong room temperature phosphorescence (OURTP) materials with continuously variable afterglow emission is of considerable practical importance in diverse optoelectronic applications but remains a formidable challenge. Here, we present an effective strategy for on-demand engineering of afterglow color in water-soluble polymeric systems via efficient phosphorescence Förster resonance energy transfer. Using a blue afterglow emitting water-soluble polymer as host and a series of fluorescent emitters with varied emissive colors as guests, afterglow emission is rationally modulated, conferring the full-color afterglow emission ranging from blue to red and even white with ultralong lifetimes up to 4.2 s and photoluminescence quantum yields of 36%.These water-soluble multicolor-emitting polymeric afterglow systems can function as OURTP security inks, and multilevel information encryption was successfully established by RGB-based multicolor security printing. These results present important guidance in developing high-performance afterglow polymers with on-demand color tuning ability for remarkable optoelectronic applications.

Harmonizing conjugated and non-conjugated emission for amorphous blue organic afterglow through copolymerization and aggregation engineering

“…Organic ultralong room-temperature phosphorescence (OURTP) materials with long (>100 ms) photoluminescent (PL) lifetimes under ambient conditions for organic afterglow have captured enormous attention recently 1–4 due to their spectacular emission behaviors and broad application prospects in displays, biological imaging, chemical sensors, and information encryption/anti-counterfeiting. 5–11 With continuous efforts toward improving OURTP performances, purely organic afterglow materials without heavy metal elements have shown great progress in emission color from yellow to deep-blue and near-infrared, 12–14 in phosphorescent yields ( Φ p ) up to 96.5% of ionic crystals, 15 and in lifetimes ( τ p ) over 22.4 s when assembled in a zeolitic imidazolate framework. 16 However, it remains an intrinsic challenge to simultaneously improve Φ p and elongate the τ p of OURTP because of their inherent contradictions, where rapid radiative decay of the triplet excited state ( k T r ) for efficient phosphorescence with high Φ p inevitably leads to a short τ p .…”

All-Visible (>500 nm)-Light-Induced Diarylethene Photochromism Based on Multiplicity Conversion via Intramolecular Energy Transfer

“…Another possible mechanism for producing the triplet states of the open-ring isomer of the DAE unit is multiplicity conversion based on intramolecular energy transfer from the excited singlet state of the PBI unit to the triplet state of the DAE unit. The first example of intramolecular energy transfer between states with different multiplicities (i.e., singlet and triplet) was reported by Börjesson and co-workers, and some other successful examples have gradually been reported in the field of organic phosphorescence materials. − As shown in Figure , the energy levels of the triplet states (T 1 and T 2 ) of the open-ring isomer of the DAE unit are located at 2.28 and 2.40 eV, respectively, which are slightly lower than the energy level of the S 1 state of the PBI unit (2.42 eV) in dyad 1 . On the contrary, in the case of dyad 2 , the triplet-state energy levels of the DAE unit are located at relatively higher energy levels (≥2.60 eV).…”

Machine Learning-assisted Exploration of a Universal Polymer Platform with Charge Transfer-dependent Full-color Emission

“…In general, color-tunable fluorescence in polymer systems can be achieved either by direct emission spectra combination [17][18][19] or Förster resonance energy transfer (FRET) 20,21 . By modulation of energy transfer efficiency, the latter can generate more tunable emission properties, and is therefore widely used in stimuli-responsive materials 22,23 , ratiometric sensors 24,25 multicolor bioimaging agents 26,27 , security inks 28 , and light-harvesting systems 29 . The precise emission tuning of FRET polymers requires careful selection of donor (D) and acceptor (A) fluorophore pairs and extensive optimization of their energy transfer efficiency that depends on the inverse 6 th power of the donor-to-acceptor separation distance 30 .…”