Enhanced
Performances of PbS Quantum-Dots-Modified
MoS<sub>2</sub> Composite for NO<sub>2</sub> Detection at Room Temperature
Xin Xin
Yong Zhang
Xiaoxiao Guan
Juexian Cao
Wenli Li
Xia Long
Xin Tan
10.1021/acsami.8b20984.s001
https://acs.figshare.com/articles/journal_contribution/Enhanced_Performances_of_PbS_Quantum-Dots-Modified_MoS_sub_2_sub_Composite_for_NO_sub_2_sub_Detection_at_Room_Temperature/7752392
The modification
of the material surface by the second-phase particles
enables the electron interaction on the Fermi level or the energy
band between different materials, which can achieve the improvement
of gas-sensing properties. Herein, a novel composite of PbS quantum-dots-modified
MoS<sub>2</sub> (MoS<sub>2</sub>/PbS) is synthesized by combination
of hydrothermal method with chemical precipitation and fabricated
into the gas sensor to investigate its enhanced gas-sensing properties
caused by the modification of PbS quantum dots at room temperature.
It is found that the responsivity of MoS<sub>2</sub>/PbS is obviously
higher than that of pure MoS<sub>2</sub> gas sensor throughout the
whole test range, and MoS<sub>2</sub>/PbS gas sensor has better selectivity
compared with pure MoS<sub>2</sub> gas sensor at room temperature.
The response of MoS<sub>2</sub>/PbS gas sensor is about 50 times higher
than that of MoS<sub>2</sub> gas sensor at 100 ppm NO<sub>2</sub> concentration.
The recovery behavior is greatly improved, and the resistance of MoS<sub>2</sub>/PbS gas sensor can return completely with almost no drift
(the recovery ratio is more than 99%). The enhanced gas-sensing properties
of MoS<sub>2</sub>/PbS, which are superior to those of pure MoS<sub>2</sub>, are ascribed to the large surface area of MoS<sub>2</sub> combined with the high responsivity of PbS quantum dots for NO<sub>2</sub>. The formation of heterojunctions leads to the competitive
adsorption of the target gases, which can prevent MoS<sub>2</sub> from
being oxidized, further improving the stability of gas sensor. Furthermore,
to profoundly discuss the enhanced performances and the sensing mechanism,
the molecular models of adsorption systems are constructed to calculate
the adsorption energies and the diffusion characters of NO<sub>2</sub> via density functional theory. We expect that our work can offer
a useful guideline for enhancing the gas-sensing properties at room
temperature.
2019-02-12 00:00:00
PbS Quantum-Dots-Modified MoS 2 Composite
gas sensor
PbS quantum-dots-modified MoS 2
MoS 2
MoS 2 gas sensor
PbS quantum dots
room temperature
gas-sensing properties