Surface Plasmon Assisted Enhancement in the Nonlinear Optical Properties of Phenothiazine by Gold Nanoparticle

Abstract

We report the photophysical method for the synthesis of phenothiazine (PTZ)−gold (Au) nanocomposite (NC), by ablating a Au target in PTZ−dimethylformamide (DMF) solution using a Q-switched Nd:YAG laser delivering 7 ns pulses at 532 nm. The ablation of the Au target as well as the photoionization of PTZ was carried out simultaneously in the same medium with the same laser system. PTZ itself acts as a reducing and stabilizing agent during the formation of Au nanoparticles (NPs). The composite formation was confirmed from the Fourier transform infrared spectroscopy (FTIR) analysis and UV−visible absorption spectrum. The presence of NPs in the composite was evident from the absorption studies and transmission electron microscopy (TEM) analysis. A noticeable reduction in photoluminescence intensity was observed in the composite material, indicating the electron/energy transfer between the constituents. Nonlinear optical (NLO) studies have been done by employing the single beam Z-scan technique that uses 532 nm, 7 ns and 10 Hz laser pulses for excitation. A significant enhancement (∼67 times) in nonlinear optical absorption (NLA) was observed in the composite compared to the constituent moieties, and the reason behind the enhancement could be attributed to both the local field effect and electron/energy transfer. It is observed that the NLA mechanism for pure PTZ (two photon absorption (TPA)) differs from that of PTZ−Au NC (TPA assisted excited state absorption (ESA)). The self-defocusing nature of both the composite and pristine compounds was explored from the closed aperture Z-scan studies. The adopted strategy is found to be useful for designing novel materials with potential applications in photonics.

An insight into phenomenal optical non‐linearities arising from synergistic relationship between selected BODIPYs and noble metal nanoparticles

“…In the case of C Au hybrid system, a significant redshift in SPR maximum of Au NP from 521 to 540 nm is observed, and similarly in the case C Ag composites, there is a noticeable shift in SPR maxima from 410 to 421 nm, and it could be attributed to the change in dielectric medium and morphology changes of the NPs upon hybrid system formations. [21,28] An increasing in index refraction indicates the increase in dielectric F I G U R E 2 Normalized (a) absorption and (b) emission spectra of BODIPYs. Inset of (a) shows the zoomed area of absorption spectra around 500 nm function and hence the polarization of the medium.…”

“…If it is only genuine TPA, where two photons are simultaneously absorbed and transferred to the excited state, β eff value remains constant on increasing input intensity because of insignificant ground state depletion. [28] Hybridization of NLO active material leads to an improvement of its property by an order while keeping the ultrafast response unchanged. [41][42][43][44][45][46][47] Here, an attempt was made to improve the OL properties of one of BODIPY under study.…”

Indolo[3,2‐b]carbazole‐based poly(arylene ethynylene)s through Sonogashira coupling for optoelectronic and sensing applications

“…There exist different types of mechanisms, such as the excited state absorption (ESA), nonlinear scattering, free carrier absorption, quantum confinement, and so forth for NLO absorption processes. The mechanism behind the NLA properties of ICZP1 and ICZP2 systems can be described with five level energy model, which give an idea about various changeovers occurring between the energy levels as shown in Figure . S 0 , S 1 , and S 2 represent the singlet ground state, singlet first and second excited state, whereas T 1 and T 2 represent first and second triplet excited state respectively.…”

Electronic structure and second-order nonlinear optical properties of lemniscular [16]cycloparaphenylene compounds

“…The design and synthesis of materials with large nonlinear optical (NLO) performance have attracted considerable attention due to their potential applications in optical and optoelectronic devices. [1][2][3][4][5][6][7][8] However, second-order NLO properties can be characterized at the molecular level with second-order polarizability, which is the most important point in practical applications. The necessary requirement for second-order NLO materials is a non-centrosymmetric electronic structure.…”