Pyrene-functionalized tungsten disulfide as stable resistive photosensor
Résumé
Pyrene carrying an 1,2-dithiolane linker was employed to functionalize exfoliated WS2 and the resulting
material was used in a proof-of-concept application as a photoresistor type sensor. The WS2–pyrene
hybrid material was comprehensively characterized by spectroscopic, thermal and microscopy techniques,
coupled to density functional theory modelling. The high solubility of the WS2–pyrene hybrid material allows
easy manipulation in wet media, making it suitable for device fabrication. Thus, a two-terminal resistive
photosensor was developed and tested for photodetection. The photosensitivity of WS2 was improved by
the presence of covalently attached pyrene by a factor of 2–3, the response linearly dependent on light
intensity. Device reaction time was also improved, and critically the photosensor stability was significantly
enhanced. Functionalization of exfoliated WS2 material heals vacancies, oxidation and other damage sites
liable to impede photoelectric response. This proof-of-concept study opens the way for incorporation of
diverse chromophores active in the visible and/or NIR region of the electromagnetic spectrum to WS2 in
order to stabilise it and broaden its photoresistive sensing applicability.
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