Au@HgxCd1-xTe core@shell nanorods by sequential aqueous cation exchange for near-infrared photodetectors

Xinyuan Li, Muhammad Ahsan Iqbal, Meng Xu, Yi Chi Wang, Hongzhi Wang, Muwei Ji, Xiaodong Wan, Thomas J.A. Slater, Jia Liu, Jiajia Liu, Hongpan Rong, Wenxing Chen, Stephen V. Kershaw, Sarah J. Haigh, Andrey L. Rogach, Liming Xie*, Jiatao Zhang

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

40 Citations (Scopus)

Abstract

We have explored the synthesis of Au@HgxCd1-xTe core@shell nanorods by sequential aqueous cation exchange (ACE) for near-infrared photodetector application. A number of related Au@telluride core/shell nanorod structures were put forwarded, taking advantage of multi-step transformations through a binary and then a ternary phase for the telluride shells. The latter have a high degree of crystallinity thanks to the step-wise ACE method. The use of only trace amounts of Cd2+ coordinated with tri-n-butylphosphine, assisted the phase transformation from an amorphous Ag2Te shell to a highly crystalline Ag3AuTe2 shell in the first stage; this was followed by a further cation exchange (CE) step with far higher Cd2+ levels to fabricate a highly crystalline CdTe shell, and with an additional CE with Hg2+ to convert it to a HgxCd1-xTe shell. The composition of the shell components and the well-controlled thickness of the shells enabled tunable surface plasmon resonance properties of the Au@telluride nanorods in the NIR region. Utilizing the enhanced NIR absorption, a hybrid photodetector structure of Au@HgxCd1-xTe nanorods on graphene was fabricated, showing visible to NIR (vis-NIR) broadband detection with high photoresponsivity (~106 A/W).

Original languageEnglish
Pages (from-to)57-65
Number of pages9
JournalNano Energy
Volume57
DOIs
Publication statusPublished - Mar 2019

Keywords

  • Cation exchange synthesis
  • Core/shell nanorods
  • Crystal phase engineering
  • Near-infrared photodetector

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