Methodological possibilities of positron annihilation lifetime (PAL) spectroscopy applied to characterize different types of nanomaterials treated within three-term fitting procedure are critically reconsidered. In contrast to conventional three-term analysis based on admixed positron- and positronium-trapping modes, the process of nanostructurization is considered as substitutional positron-positronium trapping within the same host matrix. Developed formalism allows estimate interfacial void volumes responsible for positron trapping and characteristic bulk positron lifetimes in nanoparticle-affected inhomogeneous media. This algorithm was well justified at the example of thermally induced nanostructurization occurring in 80GeSe2-20Ga2Se3 glass.

The influence of γ‐irradiation on the positron annihilation lifetime spectra in chalcogenide vitreous semiconductors of As‐Ge‐S system has been analysed. The correlations between lifetime data, structural features and chemical compositions of glasses have been discussed. The observed lifetime components are connected with bulk positron annihilation and positron annihilation on various native and γ‐induced open volume defects. It is concluded that after γ‐irradiation of investigated materials the γ‐induced microvoids based on S1–, As2–, and Ge3– coordination defects play the major role in positron annihilation processes.

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The phenomenon of positron–electron annihilation in lifetime measuring mode is considered as a tool to study nanostructurization in solids possessing mixed positron and positronium (Ps) trapping. Structural inhomogeneities due to guest nanoparticles in such solids are described in terms of substitution trapping in positron‐ and Ps‐related sites within the same host matrix. The developed approach allows estimation of interfacial free‐volume voids as being responsible for positron trapping and defect‐free bulk positron lifetimes of nanoparticle‐modified solids. For the example of arsenic sulfide, As4S4 nanoparticles embedded in polyvinylpyrrolidone (PVP) environment under high‐energy ball milling, an alternative algorithm to parameterize these structural imperfections is justified. Interfacial free‐volume voids between neighboring nanoparticles filled with loosely packed As4S4 crystallites are considered as the most probable positron trapping sites. The observed variations in mixed positron–Ps trapping modes under nanostructurization are adequately defined with respect to the chemistry of guest nanoparticles. Direct evidence for this algorithm is provided as the basis of experimental three‐term decomposed positron lifetime spectra for As4S4–PVP nanocomposites parameterized with respect to different fitting protocols.

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