Concept of excitons

Jai Singh, Harry E. Ruda, M. R. Narayan, D. Ompong

Research output: Chapter in Book/Report/Conference proceedingChapterpeer-review


The concept of Wannier-Mott excitons is valid for inorganic semiconductors such as Si, Ge, and GaAs, because, in these materials, the large overlap of interatomic electronic wave functions enables electrons and holes to be far apart but bound in an excitonic state. The excitonic concept from the theory point of view was initially developed only for crystalline solids, and it used to be believed that excitons cannot be formed in amorphous semiconductors. This chapter presents concepts of excitons in crystalline and amorphous solids, both inorganic and organic. In organic semiconductors, mainly Frenkel excitons are created, and the absorption of photons creating Frenkel excitons, both singlet and triplet, is described in detail. Two processes of exciting triplet excitons are described: direct excitation to the triplet through the exciton-spin-orbit-photon interaction; and indirect excitation through the intersystem crossing caused by the exciton-spin-orbit-molecular vibration interactio.

Original languageEnglish
Title of host publicationOptical Properties of Materials and Their Applications
EditorsJai Singh
PublisherJohn Wiley & Sons
Number of pages28
ISBN (Electronic)9781119506003
ISBN (Print)9781119506317
Publication statusPublished - Jan 2020


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