Charm‐Bracelet‐Type Poly(N‐vinylcarbazole) Functionalized with Reduced Graphene Oxide for Broadband Optical Limiting

Abstract

Two-dimensional graphene, discovered most recently, has been at the center of a significant research effort [1] due to its high thermal conductivity ( % 5 10 3 W m À1 K À1 , 50 % higher than that of carbon nanotubes (CNTs), and about ten times higher than metals such as copper and aluminum), [2] high Youngs modulus ( % 1100 GPa), [3] charge/hole mobility (2 10 5 cm 2 V À1 s À1 ), [1b, 2b, 4] fracture strength (125 GPa), [3] specific Brunauer-Emmett-Teller surface area (theoretical value: [5] 2630 m 2 g À1 ; experimental value measured by nitrogen adsorption at 77 K: [6] 640 m 2 g À1 ), and the quantum Hall effect. [7] Despite being only one atom thick, graphene is found to absorb a significant (a = 2.3 %) fraction of incident white light, a consequence of graphenes unique electronic structure.[8] Because of the ultrafast carrier dynamics [9] and large absorption of incident light per layer, [8] graphene should behave as a fast saturable absorber over a wide spectral range.[10] Wang et al. [11] observed a significant nonlinear optical (NLO) response of graphene dispersions to nanosecond laser pulses at 532 and 1064 nm, implying a potential broadband, optical-limiting (OL) application. Nonlinear scattering (NLS), arising from the formation of solvent bubbles and microplasmas, is the principle mechanism for OL. The surface tension of solvents has strong influence on the OL performance of graphene dispersions. We also observed the broadband NLO and OL properties of graphene families, including graphene oxide (GO) nanosheets, graphene nanosheets (GNSs), GO nanoribbons (GONRS), and graphene nanoribbons (GNRs) at 532 and 1064 nm.[12] NLS and two-photon absorption (TPA) were found to have strong effects on the NLO and OL responses of the graphene nanostructures.Like CNTs, graphene is insoluble in many organic solvents. Its thus very interesting to design and synthesize graphene-based solution-processed organic/polymeric materials, which is the key issue for the development of graphenebased molecular optoelectronic and photonic devices.[13] Up to the present moment, the chemistry of graphene reported in the literature mainly concerns the chemistry of graphene oxide (GO) [1c, 14] that has a chemically reactive oxygen functionality, including carboxylic acid groups at the edges of GO, and epoxy and hydroxyl groups on the basal planes, with fewer reports [15] investigating covalently chemical modification of reduced graphene oxide [1c, 16] (RGO). In contrast to GO, which is an electrically insulating material owing of the disrupted sp 2 bonding networks, electrical conductivity of RGO can be recovered by restoring the p network. Importantly, the preparation method for grafting organic or polymeric moieties onto the surface of RGO retained structural integrity of the RGO framework so that there is no loss of electronic structure.We have developed a new synthetic method for grafting polymers onto fullerene by treating carbanion intermediates of polymers with fullerenes (C 60 , C 70 ). [17] This strategy was applied to ...

Optical Limiting of Carboxyl–Graphene Oxide

“…Recently, some functionalized GO, such as GO-organic dye ionic complex, GO-zinc phthalocyanine, GO-N-vinylcarbazole, GO-Au, GO-NaYF 4 :Yb 3+ /Er 3+ , GO-polyaniline and GO-ZnO, have been reported [18][19][20][21][22][23][24] . The research on carboxyl-GO has manifested its potential in biology, electronics, bionics and medical domains [25][26][27][28][29] .…”

Novel conjugated patterns of PBDT‐DTNT and PBDT‐TIPS‐DTNT‐DT complicated polymers onto graphenic nanosheets

“…Nguyen and co‐workers utilized graphene–poly(3,4‐ethylenedioxythiophene):poly(styrene sulfonate) composite to improve the hole transfer in an organic device. The reduction of GO is the most efficient method for producing large amounts of reduced GO (rGO) . Suspensions of graphene and rGO have been utilized to nucleate P3HT nanofibers and modify the orientation of crystals in P3HT thin films .…”

Stable and efficient loading of silver nanoparticles in spherical polyelectrolyte brushes and the antibacterial effects

“…Poly(N-vinylcarbazole) (PVK), as a semiconductive polymer [36][37][38], displays some activity to inhibit the growth of bacteria with very little damage to human cells [39]. Hence PVK was chosen to serve as the core of SPB followed by covalent grafting of PAA shells onto the surface of PVK core by photo-emulsion polymerization.…”