Amplified spontaneous emission of fluorene fluorescent-dye-doped DNA-CTMA thin films

The 4-(9, 9-diethyl-2-(pyridin-4-yl)-9H-fluoren-7-yl) pyridine (DPFP) was synthesized via a Suzuki coupling reaction. The optical spectra properties of DPFP and DPFP-DNA-CTMA thin filmswere characterized by the measurements of the UV/VIS absorption spectrum and fluorescence spectrum. The amplified spontaneous emission (ASE) of the DPFP-DNA-CTMA thin film was studied experimentally by pumping of pulse laser with a wavelength of 355 nm. The result shows that the absorption peak is located at 333 nm and the fluorescence peaks of DPFP are 370 nm, 386 nm, 408 nm. The fluorescence spectrum of DPFP has the multi-peaks which are corresponding to the vibronic transitions from an excited state of S1 level to the ground state of S0 level. The ASE peaks of DPFP-DNA-CTMA thin films are located at 390 nm and 406 nm, and the threshold energy densities are 3.24 mJ/cm2 and 3.4 mJ/cm2, respectively. By adjusting the doped proportion of DPFP in DNA-CTMA, ASE can be realized at a specific wavelength.