Photosensitive n-Type Doping Using Perovskite CsPbX₃ Quantum Dots for Two-Dimensional MSe₂ (M = Mo and W)...

Area of Science:

• Materials Science
• Nanotechnology
• Optoelectronics

Background:

• Perovskite CsPbX3 nanostructures are luminescent, photovoltaic, and photosensitizing materials.
• Two-dimensional (2D) transition-metal dichalcogenides (TMDCs) like MSe2 are used in flexible optoelectronics.
• Perovskite quantum dots (QDs) and TMDCs offer potential for advanced electronic devices.

Purpose of the Study:

• To enhance the photoresponsive characteristics of 2D MSe2-based field-effect transistors (FETs).
• To investigate the effect of hybridizing perovskite QDs with MoSe2 and WSe2 FETs.
• To understand the underlying mechanisms of charge transfer and photogating in these hybrid systems.

Main Methods:

• Fabrication of field-effect transistors (FETs) using WSe2 and MoSe2 nanosheets.
• Hybridization of 2D TMDCs with green-light-emitting CsPbBr2I1 QDs and blue-light-emitting CsPb(Cl/Br)3 QDs.
• Characterization using laser confocal microscopy photoluminescence (PL) and electrical measurements of FET devices.

Main Results:

• Observed PL quenching in perovskite QDs hybridized with MoSe2 and WSe2, indicating charge transfer.
• Significant decrease in p-channel current and hole mobility after QD hybridization.
• Substantial increase in n-channel photocurrent and photoresponsivity under illumination.
• Negative shift in threshold voltage of FETs due to perovskite QD hybridization.

Conclusions:

• Hybridization of perovskite CsPbX3 QDs with 2D MoSe2 and WSe2 significantly enhances FET photoresponsivity.
• The observed enhancement is attributed to a photogating effect caused by trap states, leading to photosensitive n-type doping.
• These findings suggest promising applications for perovskite QD/TMDC hybrids in optoelectronic devices.