Multifunctional Self-Doped Nanocrystal Thin-Film Transistor Sensors

Dongsun Choi, Mihyeon Park, Juyeon Jeong, Hang Beum Shin, Yun Chang Choi, Kwang Seob Jeong

Research output: Contribution to journalArticlepeer-review

9 Citations (Scopus)


Self-doping in nanocrystals allows accessing higher quantum states. The electrons occupying the lowest energy state of the conduction band form a metastable state that is very sensitive to the electrostatic potential of the surface. Here, we demonstrate that the high charge sensitivity of the self-doped HgSe colloidal quantum dot solid can be used for sensing three different targets with different phases through self-doped HgSe nanocrystal/ZnO thin-film transistors: the environmental gases (CO 2 gas, NO gas, and H 2 S gas); mid-IR photon; and biothiol (l-cysteine) molecules. The self-doped quantum dot solid detects the targets through different mechanisms. The physisorption of the CO 2 gas and the NO gas molecules, and the mid-IR photodetection show reversible processes, whereas the chemisorption of l-cysteine biothiol and H 2 S gas molecules shows irreversible processes. Considering the quenching of mid-IR intraband photoluminescence of the HgSe colloidal quantum dot solid by the vibrational mode of the CO 2 gas molecule, sensing the CO 2 gas could be involved in the electronic-to-vibrational energy transfer. The target molecules are quantitatively analyzed, and the limits of detection for CO 2 and l-cysteine are 250 ppm and 10 nM, respectively, which are comparable to the performance of commercial detectors.

Original languageEnglish
Pages (from-to)7242-7249
Number of pages8
JournalACS Applied Materials and Interfaces
Issue number7
Publication statusPublished - 2019 Feb 20


  • TFT sensor
  • gas sensor
  • mid-IR photodetector
  • probe-free biosensor
  • self-doped nanocrystal

ASJC Scopus subject areas

  • Materials Science(all)


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