Electrogenerated chemiluminescence. Effect of a magnetic field on the delayed fluorescence and ECL of several systems involving excimers or exciplexes
✍ Scribed by Hiroyasu Tachikawa; Allen J. Bard
- Publisher
- Elsevier Science
- Year
- 1974
- Tongue
- English
- Weight
- 616 KB
- Volume
- 26
- Category
- Article
- ISSN
- 0009-2614
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✦ Synopsis
The use of magnetic field effects in delayed fluorescence (DF) and electrogenerated chemihrminescence (ECL) studies to obtain information about the involvement of triplet state species in reactions leading to the production of monomeric and dim&c (excimer or exciplex) excited states is described. In the room temperature DF of pyrene and 1,2-benzanthracene, identical field effects are observed for monomer and excimer emission, in agreement with a mechanism involving a common intermediate produced on triplet-triplet annihilation (TTA), and different than previous DF results for 1.2-benzmthracene solutions at low temperatures. The ECL of the pyrene/N,N,N'.N'-tetramethyl-p-phenylenediamine (TMPD) system also shows monomer and excimer emissions identically affected by magnetic field and in agreement with an ECL mechanism involving TTA. In the ECL of the S-methyhmthracene (iliA)/tri-p-tolyfamine (TPTA) system, a field effect is observed for both the 'MA* and longer wavelength emission. In this case. however, a smaller effect is observed for the longer wavelength emission. A mechanism based on TTA to form 'MA* and some direct formation of exciplex on electron transfer is proposed_