Low-Power Upconversion in Poly(Mannitol-Sebacate) Networks with Tethered Diphenylanthracene and Palladium Porphyrin

Abstract

Efforts to fabricate low-power upconverting solid-state systems have rapidly increased in the past decade because of their possible application in several fields such as bio-imaging, drug delivery, solar harvesting or displays. The synthesis of upconverting cross-linked polyester rubbers with covalently tethered chromophores is presented here. Cross-linked films were prepared by reacting a poly(mannitol-sebacate) pre-polymer with 9,10-bis(4hydroxymethylphenyl) anthracene (DPA-(CH2OH)2) and palladium mesoporphyrin IX (PdmP). These chromophores served as emitters and sensitizers, respectively, and through a cascade of photophysical events, resulted in an anti-Stokes shifted emission. Indeed, blue emission (~ 440 nm) of these solid materials was detected upon excitation at 543 nm with a green laser and the power dependence of integrated upconverted intensity vs. excitation was examined. The new materials display upconversion at power densities as low as 32 mW/cm 2 , and do not display phase de-mixing, which has been identified as an obstacle in rubbery blends comprising untethered chromophores.

Mechanical properties and degradation studies of poly(mannitol sebacate)/cellulose nanocrystals nanocomposites

“…For PMS matrix with mannitol : sebacic acid 1 : 2 stoichiometry, we have also demonstrated that the residual alcohol groups of PMS matrix serve as ideal scaffolds for covalent tethering of chromophores with potential applications as bio-based up-converting rubbery systems for drug-delivery, bio-imaging, solar harvesting or displays. 43 This previous experience demonstrates the possibility to covalently attach chromophores to a PMS matrix. In this regard, PMS/CNC nanocomposites with 1 : 2 ratio were developed and nal properties were tuned and evaluated taking into account the possibility to be inuenced either by physical and chemical CNC/PMS interactions, but in a different way than for 1 : 1 PMS system, due to the stark differences of the matrices.…”

Glassy poly(methacrylate) terpolymers with covalently attached emitters and sensitizers for low-power light upconversion

“…Therefore, glassy TTA‐UC blends with rather high content of chromophores were explored . However, incorporating high concentrations of chromophores in rubbery materials by way of blending is challenging due to phase separation . Monguzzi et al reported TTA‐UC in glassy ( T g = 67 °C) cellulose acetate films, which were produced by drop‐casting a solution containing the polymer and the dyes (palladium(II) meso‐tetraphenyltetrabenzoporphyrin and 9,10‐bis(phenylethynyl)anthracene in concentrations of 0.2 wt % or less (relative to the polymer) onto a hot glass substrate .…”

“…This study sought to explore whether the solubility of the sensitizer molecules and electronic relaxation pathways involving aggregates of the sensitizer molecules are indeed to blame. While several groups have explored the connection of emitter and sensitizer units in polymers, little has been done in the context of understanding how it impacted thick polymeric films. We therefore prepared and studied glassy terpolymers in which both the sensitizer and the emitter are covalently connected to a polymeric backbone as pendant groups.…”

Intramolecular Triplet–Triplet Annihilation Upconversion in 9,10-Diphenylanthracene Oligomers and Dendrimers

“…A large number of successful examples of TTA-UC in diffusion restrictive environments have been reported in recent years, − in particular in polymeric matrices. − Typically, systems operating under conditions with slow diffusion have had much lower efficiencies when compared to experiments carried out under conditions with fast diffusion. Higher efficiencies were found in rubbery or gel-like environments that apply less restriction to the mobility of the chromophores, − and efficiencies were highest in fluid systems. − These observations illustrate that the mobility of the chromophores in a twofold diffusion-limited TTA-UC system is crucial.…”