Multicolor, fluorescent self-healing gels were constructed through reacting carbon dots produced from different aldehyde precursors with branched polyethylenimine. The self-healing gels were formed through Schiff base reaction between the aldehyde units displayed upon the carbon dots’ surface and primary amine residues within the polyethylenimine network, generating imine bonds. The dynamic covalent imine bonds between the carbon dots and polymeric matrix endowed the gels with both excellent self-healing properties as well as high mechanical strength. Moreover, the viscoelastic properties of the gels could be intimately modulated by controlling the ratio between the carbon dots and polymer. The distinct fluorescence emissions of the gels, originating from the specific carbon dot constituents, were employed for fabrication of light emitters at different colors, particularly generating white light.

The EL decay is attributed to the transit time, and it originates from the radiative recombination of newly formed singlet excitons during the discharge of the space-charge regions.

We have studied the degradation of the photoluminescence (PL) of a phase-separated film of a polyfluorene blend, F8BT/PFO, on the submicron length scale using near-field scanning optical microscopy, visualizing the PL of blend compositions that do not exist macroscopically in equilibrium. In the initial scans, the topography and the PL were anticorrelated, as the emission was dominated by the PFO-rich phase. This behavior changed at longer illumination times, where the emission was dominated by the F8BT-rich phase; i.e., the topography and PL were correlated. Using macroscopic investigation of the mechanisms that govern the PL, we could explain the time dependence of the PL spatial distribution: while the degradation of F8BT was driven by photobleaching, both faster absorption degradation and photobleaching processes dominate the degradation of PFO. In addition, we found that energy transfer does not protect the PFO from degradation and does not improve its resistance to oxidation.

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