1. Stimulated emission from films of conjugated polymers and oligomers
- Author
-
van Hutten, PF, Brouwer, HJ, Krasnikov, VV, Gill, RE, Hadziioannou, G, Kafafi, ZH, and Polymer Chemistry and Bioengineering
- Subjects
Quantitative Biology::Biomolecules ,poly(p-phenylenevinylene) ,genetic structures ,stimulated emission ,Physics::Optics ,eye diseases ,conjugation length ,electroluminescence ,laser ,Condensed Matter::Soft Condensed Matter ,Condensed Matter::Materials Science ,block copolymers ,chromophore ,photoluminescence ,oligomers - Abstract
Oligomers and block copolymers structurally related to PPV were investigated under intense optical excitation. Their well-defined molecular structure allows a better control of emission properties than is usually feasible in semiconducting polymers. Stimulated emission is demonstrated in single crystals of PPV-type oligomers, and also in thin films obtained by spincasting of copolymers containing PPV-type blocks. Waveguiding is shown to provide the length of interaction required for mirrorless laser generation. Thin films of oligomers obtained through deposition from the vapor phase are polycrystalline, and the optical losses in the as-deposited films are too large for lasing to be achieved. These films show stimulated emission only after the domain size has been increased by annealing. Lasing occurs within individual crystalline domains with a threshold value comparable to that found for optically clear amorphous films of conjugated polymers.
- Published
- 1997