1T	Tetragonal
2D	Two-dimension
2H	Hexagonal
3R	Rhombohedral
Δω	Raman shift between the peak positions of E12g and A1g
ALD	Atomic layer deposition
A1g	MoS2 out-of-plane Raman vibration mode
BL	Buffer layer
CNTs	Carbon nanotubes
CVD	Chemical vapor deposition
DFT	Density-functional theory
E12g	MoS2 in-plane Raman vibration mode
ETL	Electron transport layer
EQE	External quantum efficiency
FEE	Field electron emission
FET	Field-effect transistor
Gr	Graphene
HIT	Heterojunction with intrinsic thin layer
HLDG	Hybrid Lorentz-Drude-Gaussian model
HNPs	Hexagonal-shaped nanoplates
HRTEM	High-Resolution Transmission Electron Microscopy
J-V	current density versus voltage
Jsc	Short circuit current density
KPFM	Kelvin probe force microscopy
LSPR	Localized surface plasmon
NPs	Nanoparticles
NSs	Nanosheets
PCE	Power conversion efficiency
PDMS	Polydimethylsiloxane polymer
PL	Photoluminescence
PLD	Pulsed laser deposition
PPB	Particles per billions
PPM	Particles per millions
PSCs	Perovskite solar cells
Ra	Resistance of the sensing element in the presence of atmospheric air
Rg	Resistance of the sensing element in the presence of the target gas
RH	Relative humidity
SCs	Solar cells
SEM	Scanning electron microscopy
Smax	The maximum value of the sensing response
SP	Surface potential
TCE	Transparent conducting electrode
TEM	Transmission electron microscopy
TD	Thermal decomposition
TMDs	Transition metal dichalcogenides
TRPL	Time-resolved photoluminescence
TVD	Thermal vapor deposition
TVS	Thermal vapor sulfurization
UV	Ultraviolet
Voc	Open circuit voltage
XPS	X-ray photoelectron spectroscopy