Optical Properties Of Organic Polymers And Small Molecules

A new important step in organic photoluminescence(OPL) and electroluminescence(OEL) is the demonstration of organic/polymer lasing. The studies on organic lasers are very important because of not only the low threshold lasing behaviors, but also a promise as electric-pumping lasing. So it is very important and meaningful to study the optical characteristics of new types organic materials as the gain medium in laser.The optical characteristics of three new type organic materials were investigated and filtered to be as a laser material theoretically and experimentally. These new organic materials include hyperbanched polyfluorene TPA20, typical polythiophene material POTVTH-TH and small organic molecules with blue emitting DPPPB, 2PPPB. The spectra properties of these four type organic materials were investigated with absorption spectroscopy, fluorescence emission and time-resolved fluorescence spectroscopy etc. We also got their florescent quantum yields and stimulated emission cross sections by the spectra data above. According to their optical characterization data it was found that blue emitting organic material 2PPPF was the best light-emitting material comparing with the other materials with its fluorescence life time was 1.67ns, fluorescence quantum yield was 51.3%, stimulated emission cross section was 8.53×10-19m2. So we chose 2PPPF as the gain medium in the next research.We constructed light emitting experimental setup and did some work on optical-pumped polymer laser. Laser in red wavelength region was fabricated using the toluene solution of MEH-PPV as the gain medium. The emission peak was located at 565nm. The last part of our research was doing some emitting research on pyrene functioned small molecule material 2PPPB which was studied for the first time. The stimulated emission of the sample peaks was at 402nm with its full width at half maximum(FWHM) is 50nm.