Quantized molecular intercalations of Rhodamine 6G laser dye onto polymethylmethacrylate host exciplex

Abstract

Polymethylmethacrylate (PMMA) and Rhodamine 6G (R6G), were used to achieve an electronically excited R6G/PMMA complex of definite stoichiometry as an active laser exciplex, pumped by different laser sources. This paper is the first that is capable of interpretation of the interactions of the reactants to form the exciplex on the molecular level using DFT. The system was prepared by thermochemical polymerization, and structurally identified using FTIR, XRD and SEM in conjunction with DSC. In low-to moderate-loading of R6G, FTIR and XRD studies indicated a good interaction between PMMA and R6G to give poor-or semi-crystalline structures. Higher dye loadings were achieved for the synthesized exciplex; loading of PMMA with 0.25 Wt-% R6G decreased the glass transition temperature from 98.74 °C to 70.08 °C. However, increasing the loading with R6G to 5 Wt-% and 20 Wt-% increased the Tg values to 86.26 and 91.90 °C, respectively. MD simulations were conducted; the electronic mobility within the system was related to different quantum parameters, EHOMO, ELUMO, η, μ and ω were about -7.671 eV, -5.241 eV, 1.215 eV, -6.456 eV and 17.1522 eV, respectively. DFT calculations indicated that R6G/PMMA has a characteristic lasing stability, so that the lasing lifetimes about 8000 pulses and efficiencies about 21% were obtained.