RESUMEN
The structural and photoluminescence (PL) properties of thin films of poly(3-hexylthophene) (P3HT) with molecular weights (MWs) of 3000 and 13,300 have been investigated. Although high MW P3HT always self-organizes into one packing structure (form I), low MW P3HT forms two different packing structures (forms I and II) depending on the fabrication conditions. In this work, several fabrication techniques have been examined to obtain form II samples with little inclusion of a form I component. It is found that drop-cast thin films of low MW P3HT (form II) exhibit a PL spectrum that is different from that of form I and does not contain the form I component. The PL spectrum can thus be attributed to form II. The differences in PL properties between forms I and II can be understood in terms of weakened interchain interactions due to the longer interchain distance in form II.
RESUMEN
The photoluminescence properties of a thermally activated delayed fluorescence emitter, 1,2-bis(carbazol-9-yl)-4,5-dicyanobenzene (2CzPN), doped in a host matrix consisting of 1,3-bis(9-carbazolyl)benzene and a polar inert molecule, camphoric anhydride (CA), in various concentrations have been investigated. It is found that the addition of CA stabilizes only the lowest singlet excited state (S1) of 2CzPN without changing the energy level of the lowest triplet excited state (T1), leading to a reduction in the energy gap between S1 and T1. The maximum reduction of energy gap achieved in this work has been determined to be around 65 meV from the shift of the fluorescence spectrum and the temperature dependence of the photoluminescence decay rate.
RESUMEN
Luminescent thin films composed of thermostable lanthanide coordination polymers on glass electrodes were prepared using a novel combination of micelle reactions and electrochemical deposition techniques. The micelle-encapsulated luminescent polymers were obtained by the polymerization of [Eu(hfa)3 ] (hfa=hexafluoroacetylacetonate) with bridging phosphine oxide ligands in micelles using a redox-active ferrocenyl-containing surfactant in water. Films were electrochemically deposited on indium tin oxide coated glass electrodes by potentiostatic polarization of micelle-encapsulated EuIII coordination polymers. The luminescence properties of the electrochemically deposited films were characterized by measuring their emission spectra, emission lifetimes and emission quantum yields.
