TY - JOUR

T1 - Light-Activated Sub-ppm NO2 Detection by Hybrid ZnO/QD Nanomaterials vs. Charge Localization in Core-Shell QD

AU - Chizhov, Artem

AU - Vasiliev, Roman

AU - Rumyantseva, Marina

AU - Krylov, Ivan

AU - Drozdov, Konstantin

AU - Batuk, Maria

AU - Hadermann, Joke

AU - Abakumov, Artem

AU - Gaskov, Alexander

PY - 2019/9/24

Y1 - 2019/9/24

N2 - New hybrid materials—photosensitized nanocomposites containing nanocrystal heterostructures with spatial charge separation, show high response for practically important sub-ppm level NO2 detection at room temperature. Nanocomposites ZnO/CdSe, ZnO/(CdS@CdSe), and ZnO/(ZnSe@CdS) were obtained by the immobilization of nanocrystals—colloidal quantum dots (QDs), on the matrix of nanocrystalline ZnO. The formation of crystalline core-shell structure of QDs was confirmed by HAADF-STEM coupled with EELS mapping. Optical properties of photosensitizers have been investigated by optical absorption and luminescence spectroscopy combined with spectral dependences of photoconductivity, which proved different charge localization regimes. Photoelectrical and gas sensor properties of nanocomposites have been studied at room temperature under green light (λmax = 535 nm) illumination in the presence of 0.12–2 ppm NO2 in air. It has been demonstrated that sensitization with type II heterostructure ZnSe@CdS with staggered gap provides the rapid growth of effective photoresponse with the increase in the NO2 concentration in air and the highest sensor sensitivity toward NO2. We believe that the use of core-shell QDs with spatial charge separation opens new possibilities in the development of light-activated gas sensors working without thermal heating.

AB - New hybrid materials—photosensitized nanocomposites containing nanocrystal heterostructures with spatial charge separation, show high response for practically important sub-ppm level NO2 detection at room temperature. Nanocomposites ZnO/CdSe, ZnO/(CdS@CdSe), and ZnO/(ZnSe@CdS) were obtained by the immobilization of nanocrystals—colloidal quantum dots (QDs), on the matrix of nanocrystalline ZnO. The formation of crystalline core-shell structure of QDs was confirmed by HAADF-STEM coupled with EELS mapping. Optical properties of photosensitizers have been investigated by optical absorption and luminescence spectroscopy combined with spectral dependences of photoconductivity, which proved different charge localization regimes. Photoelectrical and gas sensor properties of nanocomposites have been studied at room temperature under green light (λmax = 535 nm) illumination in the presence of 0.12–2 ppm NO2 in air. It has been demonstrated that sensitization with type II heterostructure ZnSe@CdS with staggered gap provides the rapid growth of effective photoresponse with the increase in the NO2 concentration in air and the highest sensor sensitivity toward NO2. We believe that the use of core-shell QDs with spatial charge separation opens new possibilities in the development of light-activated gas sensors working without thermal heating.

KW - CdSe quantum dots

KW - charge spatial localization

KW - core/shell heterostructures

KW - room temperature semiconductor gas sensor

KW - sub-ppm NO detection

KW - visible light activation

KW - ROOM-TEMPERATURE

KW - NITROGEN-DIOXIDE DETECTION

KW - sub-ppm NO2 detection

KW - ZINC-OXIDE

KW - LIQUID PLASMA SPRAY

KW - SENSORS

KW - CDSE

KW - QUANTUM DOTS

KW - SNO2

KW - UV-LIGHT

KW - GAS-SENSING PROPERTY

UR - http://www.scopus.com/inward/record.url?scp=85073033888&partnerID=8YFLogxK

U2 - 10.3389/fmats.2019.00231

DO - 10.3389/fmats.2019.00231

M3 - Article

AN - SCOPUS:85073033888

VL - 6

JO - Frontiers in Materials

JF - Frontiers in Materials

SN - 2296-8016

M1 - 231

ER -