posted on 2023-11-29, 14:40authored byJun-Hee Park, Hong-Rae Kim, Moon-Ju Kim, Zhiquan Song, Min-Jung Kang, Dong Hee Son, Jae-Chul Pyun
A defect-passivated photosensor based
on cesium lead bromide (CsPbBr3) perovskite quantum dots
(QD) was fabricated using parylene
films, and the photosensor was applied for the microbial detection.
The CsPbBr3 perovskite QDs were synthesized to be homogeneous
in size under thermodynamic control, and the perovskite QD-based photosensor
was fabricated using MoS2 flakes as the electron transfer
layer. In this work, a parylene film with functional groups was deposited
on a photosensor for physical protection (waterproof) and defect (halide
vacancy) passivation of the perovskite QD. As the first effect of
the parylene film, the physical protection of the perovskite QD from
water was estimated by comparing the photosensor performance after
incubation in water. As the second effect of the parylene, the interaction
between the functional groups of the parylene film and the halide
vacancies of the perovskite QDs was investigated through the bandgap,
crystal structure, and trap-state density analysis. Additionally,
density functional theory analysis on Mulliken charges, lattice parameters,
and Gibbs free energy demonstrated the effect of the defect passivation
by parylene films. Finally, the parylene-passivated QD-based photosensor
was applied to the detection of two kinds of food-poisoning and gastroduodenal
disease bacteria (Listeria monocytogenes and Helicobacter pylori).