What do nonlinear optical spectroscopy and picosecond photinduced absorption have to say about excited states in conjugated polymers?

Abstract

We present a self-consistent picture of the excited state energy spectrum of poly(para-phenylene vinylene) based on theoretical calculations of exicted states and and experimental electroabsorption (EA) and picosecond photoinduced absorption measurements (PA). Our calculations place the one electron—one hole continuum ( nB u ) at 0.9 ± 0.2 eV above the 1 B u exciton. This is in agreement with EA and ps PA in the i.r., which finds an even-parity exciton (the mA g ) about 0.7 eV away from the 1 B u . The high energy ps PA at 1.5–1.7 eV is to a biexciton whose energy is consistent with our estimates.