Energy Transfer Mediated Fluorescence from Blended Conjugated Polymer Nanoparticles

Abstract

Nanoparticles consisting of a derivative of the blue-emitting conjugated polymer polyfluorene doped with green-, yellow-, and red-emitting conjugated polymers were prepared by a reprecipitation method. The nanoparticles can be described as a system of densely packed chromophores that exhibit efficient energy transfer from the host to the dopant polymers. Fluorescence quenching analysis of the host polymer as a function of the dopant concentration indicates that one energy acceptor molecule can effectively quench 90% of the fluorescence of a nanoparticle consisting of 100-200 host conjugated polymer molecules. A nanoparticle energy transfer model was developed that successfully describes the quenching behavior of a small number of highly efficient energy acceptors per nanoparticle. The fluorescence brightness of the blended polymer nanoparticles was determined to be much higher than that of inorganic quantum dots and dye-loaded silica particles of similar dimensions. The combination of high fluorescence brightness and tunable fluorescence of these blended nanoparticles is promising for ultrasensitive fluorescence-based assays.

Quantum efficiency enhancement in film by making nanoparticles of polyfluorene

“…In the recent reports, various methods have been previously shown for the formation of organic NPs [12][13][14][15][16][17][18][19][20][21]. These include mini-emulsion process [12], hydrothermal synthesis [17], and reprecipitation [13,14,[18][19][20][21].…”

Non-radiative resonance energy transfer in bi-polymer nanoparticles of fluorescent conjugated polymers

“…The third and last approach, which has been recently developed for several materials, is the combination of donor nanoparticles and acceptor nanoparticles in form of physical mixtures. Nanostructures used for such purposes are mixtures of NCs [15], two metal NPs [16], polymer nanoparticle blends prepared via the reprecipitation or the mini-emulsion methods either by mixing of polymer solutions and then forming NPs or first the formation of polymer NPs and then mixing of NP dispersions [1,2,[17][18][19]. Also, recently blends of polymers and dyes have been described by McNeill and associates.…”

Fluorene-based macromolecular nanostructures and nanomaterials for organic (opto)electronics

“…Doped nanoparticles offer ideal models to investigate energy transfer-mediated fluorescence. McNeill and co-workers [207] investigated the CPs of PF-01a (PDHF) doped with PF-06 (PFPV), PF-04a (F8BT) and MEH-PPV. Doped PF-based nanoparticles prepared via re-precipitation tend to be spherical with a size of less than 30 nm; they are estimated to contain 100-200 polymer molecules per nanoparticle.…”

“…The advantages of PF-suspended nanoparticles over polymer solutions have been systemically demonstrated by the McNeill group. PF-based CPNs generally have a quantum yield level of 10-20% in suspension or dispersion [191,207]. The highest fluorescence quantum yields of PF-01b (PFO)-suspended nanoparticles have been determined to be as high as 40% [219].…”