title: Ultrafast intersystem-crossing in platinum containing π-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 π-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 π-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.
authors.affiliation: 1] Department of Physics & Astronomy, University of Utah, Salt Lake City, Utah 84112, USA [2] School of Electronic and Optical Engineering, Nanjing University of Science and Technology, Nanjing, Jiangsu, 210094, China [3].
authors.forename: C-X
authors.initials: CX
authors.lastname: Sheng
authors.forename: S
authors.initials: S
authors.lastname: Singh
authors.forename: A
authors.initials: A
authors.lastname: Gambetta
authors.forename: T
authors.initials: T
authors.lastname: Drori
authors.forename: M
authors.initials: M
authors.lastname: Tong
authors.forename: S
authors.initials: S
authors.lastname: Tretiak
authors.forename: Z V
authors.initials: ZV
authors.lastname: Vardeny
references.citation: Langmuir. 2011 Jul 5;27(13):8377-83
references.pmid: 21627143
references.citation: Nature. 2001 Oct 25;413(6858):828-31
references.pmid: 11677602
references.citation: J Am Chem Soc. 2004 Dec 1;126(47):15388-9
references.pmid: 15563159
references.citation: J Am Chem Soc. 2012 Dec 5;134(48):19661-8
references.pmid: 23126491
references.citation: Phys Rev B Condens Matter. 1993 Jul 15;48(3):1433-1459
references.pmid: 10008503
references.citation: Nature. 2006 Apr 13;440(7086):908-12
references.pmid: 16612378
references.citation: J Phys Chem B. 2010 Nov 18;114(45):14440-9
references.pmid: 20469901