Hybrid CdSe Nanoparticle–Carbazole Dendron Boxes: Electropolymerization and Energy‐Transfer Mechanism Shift

Abstract

Carbazole containing ligand dendrons are designed based on second generation polybenzyl ether dendrons (2GPO). This is subsequently used for directly synthesizing and capping CdSe nanoparticles in contrast to ligand exchange for introducing functionality. The stable hybrid CdSe‐2GPO quantum dot nanoparticles have characteristic energy‐transfer properties from the donor carbazole peripheral groups to the acceptor CdSe nanoparticles, i.e., overlap of the fluorescence of the carbazole with the absorbance of the CdSe nanoparticle resulting in an enhanced fluorescence with concentration through Förster resonance energy transfer (FRET). However, electropolymerization of the peripheral electroactive carbazole units result in a red‐shift in absorbance and quenching in fluorescence. This is attributed to a reversed molecular orbital energy order with respect to the electropolymerized carbazole dendron and CdSe nanoparticle. The hole‐transfer results in fluoresence quenching and charge transfer between the CdSe nanoparticles and the polycarbazole peripheral units. The photoelectric alteration may yet provide for an interesting electro‐optical or sensing device application based on electrochemical properties of the hybrid material.

Nanocomposite p‐n Junction Polycarbazole CdSe/TiO2 Thin Films on ITO via Electrochemical Crosslinking

“…Figure 6 shows the result of CV on the as‐fabricated Cbz‐TiO 2 /PVK hybrid film. Our previous report32 on the interplay of Cbz‐bearing dendron boxes and CdSe NPs described a simple strategy to accomplish crosslinking in such systems: we cycled the potential between 0 V (no CdSe embedded in the film, Figure 6) or −0.2 V (CdSe embedded in the film, vide infra) and 0.8 V, whilst common potential windows go up to 1.2–1.4 V 6, 12. We decided to keep 0.8 V as upper threshold for the crosslinking of the Cbz‐TiO 2 /PVK film to compare the results.…”

“…The working electrode was the ITO‐coated glass substrate bearing the hybrid film; tetrabutylammonium hexafluorophosphate [Bu 4 N][PF 6 ] (0.1 M in CH 3 CN) was used as supporting electrolyte along with the cyclic potential sweep technique. The potential windows were 0–0.8 V (Cbz‐TiO 2 /PVK films) or −0.2−0.8 V32 (scan rate: 20 mV · s −1 ) for 20 cycles.…”

The role of (photo)electrochemistry in the rational design of hybrid conducting polymer/semiconductor assemblies: From fundamental concepts to practical applications

“…Polymer formation is based on electrochemical crosslinking, and therefore it is different from the previously shown examples in various aspects [65,66]. As seen in Fig.…”

Orderly Ultrathin Films Based on Perylene/Poly(N‐vinyl carbazole) Assembled with Layered Double Hydroxide Nanosheets: 2D Fluorescence Resonance Energy Transfer and Reversible Fluorescence Response for Volatile Organic Compounds

“…The presence of FRET in a D/A system can be identifi ed from quenching of both the fl uorescence intensity and the reduced lifetime of the donor. The weightedaverage lifetime was obtained by multiple-exponential fi tting not only to confi ne the perylene@PVK within a 2D nanospace, thus reducing the intermolecular distance and providing a favorable condition for the FRET process, but also to improve the homogenous distribution of the perylene within the PVK matrix in the 2D interlayers, preventing fl uorescence quenching and obtaining optimal fl uorescence at a 0.88, [ 22 ] a QD-based DNA nanosensor: 0.43, [ 23 ] a nanoparticle system: 0.81, [ 24 ] and QD-SWCNT conjugates: 0.91 [ 25 ] ). On the other hand, in toluene vapor, the average lifetime of PVK at 380 nm recovered to 5.65 ns, while that of perylene at 460 nm was decreased to 4.07 ns, which implies the the FRET process was off.…”