Luminescence of nanocrystalline ZnS: Pb2+

A.A. Bol, A. Meijerink

Research output: Contribution to journalArticleAcademicpeer-review

77 Citations (Scopus)

Abstract

Nanocrystalline ZnS : Pb2+ is synthesised via a precipitation method. The influence of the size of the nanocrystals and the sulfide concentration used in the synthesis on the luminescence properties is investigated. Nanocrystalline ZnS : Pb2+ shows a white emission under UV excitation with a rather high quantum efficiency (∼5%). At least two luminescence centres are involved. One centre is identified as a Pb2+ ion located on a regular Zn2+ site and gives a red emission under 480 nm excitation. The luminescence properties of this emission are characteristic of 3P01S0 (A-band) or charge transfer (D-band) transitions on Pb2+ ions. The other centres are not as well defined and give a broad green emission band under 380 nm excitation and also show luminescence properties typically observed for Pb2+. The green emission probably originates from a charge-transfer like D-band emission of Pb2+ in ZnS close to a defect (e.g. an S2- vacancy or an O2- ion on an S2- site). A relation between the temperature quenching of the emissions and the band gap is observed and indicates that photoionisation occurs. The higher quenching temperature for the Pb2+ luminescence in smaller particles can be explained by widening of the band gap as a result of quantum size effects in the ZnS host.

Original languageEnglish
Pages (from-to)2105-2112
Number of pages8
JournalPhysical Chemistry Chemical Physics
Volume3
Issue number11
DOIs
Publication statusPublished - 9 Aug 2001
Externally publishedYes

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