Experimental and Theoretical Study on the One- and Two-Photon Absorption Properties of Novel Organic Molecules Based on Phenylacetylene and Azoaromatic Moieties

Marcelo G. Vivas (1) , Daniel L. Silva (1) , Leonardo de Boni (1) , Yann Bretonniere (2) , Chantal Andraud (2) , Florence Laibe-Darbour (2) , J.-C. Mulatier (2) , Robert Zaleśny (3) , Wojciech Bartkowiak (3) , Sylvio Canuto (1) , Cleber R. Mendonca (1)

1 IFSC-USP - Instituto de Física de São Carlos
2 LC - Laboratoire de Chimie - UMR5182
3 Wroclaw University of Science and Technology

This Article reports a combined experimental and theoretical analysis on the one and two-photon absorption properties of a novel class of organic molecules with a π-conjugated backbone based on phenylacetylene (JCM874, FD43, and FD48) and azoaromatic (YB3p25) moieties. Linear optical properties show that the phenylacetylene-based compounds exhibit strong molar absorptivity in the UV and high fluorescence quantum yield with lifetimes of approximately 2.0 ns, while the azoaromatic-compound has a strong absorption in the visible region with very low fluorescence quantum yield. The two-photon absorption was investigated employing nonlinear optical techniques and quantum chemical calculations based on the response functions formalism within the density functional theory framework. The experimental data revealed well-defined 2PA spectra with reasonable cross-section values in the visible and IR. Along the nonlinear spectra we observed two 2PA allowed bands, as well as the resonance enhancement effect due to the presence of one intermediate one-photon allowed state. Quantum chemical calculations revealed that the 2PA allowed bands correspond to transitions to states that are also one-photon allowed, indicating the relaxation of the electric-dipole selection rules. Moreover, using the theoretical results, we were able to interpret the experimental trends of the 2PA spectra. Finally, using a few-energy-level diagram, within the sum-over-essential states approach, we observed strong qualitative and quantitative correlation between experimental and theoretical results.

Domaines: Catalyse; Matériaux; Chimie organique; Chimie inorganique

Marcelo G. Vivas, Daniel L. Silva, Leonardo de Boni, Yann Bretonniere, Chantal Andraud, et al.. Experimental and Theoretical Study on the One- and Two-Photon Absorption Properties of Novel Organic Molecules Based on Phenylacetylene and Azoaromatic Moieties. Journal of Physical Chemistry B, 2012, 116 (50), pp.14677-14688. ⟨10.1021/jp310731t⟩. ⟨hal-01245535⟩