Ultrafast intersystem-crossing in platinum containing ?-conjugated polymers with tunable spin-orbit coupling.

ABSTRACT: The development of efficient organic light-emitting diodes (OLED) and organic photovoltaic cells requires control over the dynamics of spin sensitive excitations. Embedding heavy metal atoms in ?-conjugated polymer chains enhances the spin-orbit coupling (SOC), and thus facilitates intersystem crossing (ISC) from the singlet to triplet manifolds. Here we use various nonlinear optical spectroscopies such as two-photon absorption and electroabsorption in conjunction with electronic structure calculations, for studying the energies, emission bands and ultrafast dynamics of spin photoexcitations in two newly synthesized ?-conjugated polymers that contain intrachain platinum (Pt) atoms separated by one (Pt-1) or three (Pt-3) organic spacer units. The controllable SOC in these polymers leads to a record ISC time of <~1?ps in Pt-1 and ~6?ps in Pt-3. The tunable ultrafast ISC rate modulates the intensity ratio of the phosphorescence and fluorescence emission bands, with potential applications for white OLEDs.

SUBMITTER: Sheng CX 

PROVIDER: S-EPMC3772376 | biostudies-literature | 2013

REPOSITORIES: biostudies-literature