Color-Tunable Resonant Photoluminescence and Cavity-Mediated Multistep Energy Transfer Cascade

Abstract

Color-tunable resonant photoluminescence (PL) was attained from polystyrene microspheres doped with a single polymorphic fluorescent dye, boron-dipyrrin (BODIPY) 1. The color of the resonant PL depends on the assembling morphology of 1 in the microspheres, which can be selectively controlled from green to red by the initial concentration of 1 in the preparation process of the microspheres. Studies on intersphere PL propagation with multicoupled microspheres, prepared by micromanipulation technique, revealed that multistep photon transfer takes place through the microspheres, accompanying energy transfer cascade with stepwise PL color change. The intersphere energy transfer cascade is direction selective, where energy donor-to-acceptor down conversion direction is only allowed. Such cavity-mediated long-distance and multistep energy transfer will be advantageous for polymer photonics device application.

Coupled Whispering Gallery Mode Resonators via Template‐Assisted Assembly of Photoluminescent Microspheres

“…While the laser irradiates only one sphere, scattering from the laser spot, as well as leakage from the sphere results in the excitation of both microspheres. Depending on the location of the incident beam, a high‐intensity light spot arises on the opposite side of the sphere and into the neighboring sphere, while suggestive of lasing behavior, it can also be related to sphere‐to‐sphere energy transfer as demonstrated by Okada and Kushida et al for coupled doped polystyrene and coupled conjugated polymer microspheres (Figure a) …”

Regioisomeric BODIPY Benzodithiophene Dyads and Triads with Tunable Red Emission as Ratiometric Temperature and Viscosity Sensors

“…In recent years, TICT rotors based on the BODIPY dyes have been utilized efficiently for temperature sensing as well as for imaging of cellular local micro viscosity using fluorescence lifetime imaging (FLIM). However, red emissive BODIPY derivatives with temperature and viscosity sensing capability are extremely rare in the literature …”

“…[36] In recent years, TICT rotors [25] based on the BODIPY dyes [37][38][39][40] have been utilized efficiently for temperature sensing [9] as well as for imaging of cellular local micro viscosity using fluorescence lifetimei maging (FLIM). However,r ed emissiveB ODIPY derivatives [41][42][43] with temperature and viscosity sensing capability are extremelyr are in the literature. [44] Challenges in the development of ratiometric temperature/ viscosity molecular probes for sensing ande specially for bioimaging applications include the development of photostable rotors with red emission for deeper tissue penetration and large Stokes shift for minimal autofluorescence.…”

π-Conjugated nanostructured materials: preparation, properties and photonic applications

“…94 Conjugated polymer-based nano/microparticles have started to attract attention as optical nano/microcavities for lasing applications because of their high refractive indices, high absorptivity, high PL efficiency, and simple preparation methods. [95][96][97][98][99][100][101][102][103] Microcavities conne light with narrow resonance frequencies and have a variety of applications, including laser resonators, photon pair generation, and biosensors. A microcavity consists of a dielectric as a resonator and a uorescent dye to provide the optical activity.…”

“…The average Q-factor is dened as the peak wavelength divided by the full-width at the half maximum of the observed WGM PL peaks (Q av ). [100][101][102][103] Conjugated polymer-based microspheres have been used in single-component white-colour resonant micro-photoemitters. White PL was generated from microspheres composed of selfassembled polycarbazole polymer chains (PCz).…”