Abstract
The interaction of pyrromethene (PM‐597) laser dye with binary mixture of [1‐butyl‐3‐methylimidazolium tetrafluoro‐borate (BMIM BF4)] ionic liquid with water [BMIM BF4: H2O] as binary eco‐friendly solvent, were investigated experimentally and theoretically by means of photophysical properties, amplified spontaneous emission (ASE), photostability, electronic ground state of molecular structures of PM‐597, BMIM BF4 and mixture of (PM‐597/BMIM BF4) using the density functional theory (DFT) technique, molecular orbitals, energy gap (Eg) among HOMO and LUMO, and the maps of molecular electrostatic potential (MESP) for PM‐597 and mixture of (PM‐597/BMIM BF4) in gas phase were calculated using B3LYP/6‐31G(d) level of theory. The refractive index (nD) and density (ρ) values for binary mixes of ionic liquid with water [BMIM BF4: H2O] with different ratios, increases as molecular mass of ionic liquid (BMIM BF4) in water increases. The frequency doubling Nd‐YAG laser of 532 nm was used to investigate amplified spontaneous emission (ASE). Aside from that, the efficiency of energy conversion was explored. Efficiency is relatively high, and 20.6% was achieved, with good photostability in case of 5 × 10−4 mol/L of PM‐597 in binary mixture of [90% BMIM BF4: 10% H2O] that was a decrease to ~48.3% of the initial amplified spontaneous emission, this output energy was observed after pumping by 72,000 shots at relatively high repetition rate (10 Hz) and pumping energy (40 mJ). In this research, we had used the mixture of [(BMIM BF4: H2O] with different ratios, as binary eco‐friendly solvent instead of harmful organic solvents.
Hazardous organic solvents can be replaced by eco‐friendly binary solvents to improve safety and environmental friendliness. The best ratio for binary mixture was BMIM BF4:10% H2O, which gave high performance and photostability for PM‐597 laser dye. There is a good agreement between experimental and theoretical results.