Electron donor-acceptor terminology

Rather than introduce new words into an already confusing terminology, Bell (64) is of the opinion that the words acid and base should be confined to proton acids, and the Sidgwick classification of molecules as electron donor and electron acceptor (which is essentially equivalent to the Lewis classification of acids and bases) be employed, together with the categories of nucleophilic and electrophilic reagents as defined by Ingold (65). 

A subset of Lewis acids and Lewis bases is represented by Brpnsted acids and Bronsted bases. Whilst Lewis acids are electron accepters and Lewis bases are electron-donors, Bronsted acids are defined as hydrogen (or proton) donors and Bronsted acids are defined as hydrogen (or proton) acceptors. The occurrence of Bronsted acid-base interactions thus is less general than that of Lewis acid-base interactions. Because of its wider application and to avoid confusion, the Lewis terminology is the preferred one in this work. 

It is convenient to adopt the terminology of Miller et al. (1977) and define a center to be an electron trap if e e p and a hole trap if the reverse is true. In addition, a minority-carrier trap is one for which the emission rate of minority carriers emin is greater than that of majority carriers emaj, whereas for majority-carrier traps emaj emin. By these definitions, an electron trap is a majority-carrier trap in an n-type region and a minority-carrier trap in p-type. Note that these definitions are independent of whether the trap is a donor or an acceptor, terms that imply a specific charge state of the center (Pantelides, 1978). Because the emission rates are thermally activated [Eq. (9)], an electron trap usually lies in the upper half of the band gap and a hole trap in the lower. 

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