Laser-Induced Photothermal Conversion to Hemispherical MoS₂ Enabling Non-Contact Self-Powering Image Sensor

Area of Science:

• Materials Science
• Nanotechnology
• Energy Harvesting

Background:

• Molybdenum disulfide (MoS₂) shows promise for triboelectric nanogenerators (TENGs) due to its negative triboelectric properties, transparency, and flexibility.
• Conventional 2D MoS₂-based TENGs face limitations like mechanical wear and reduced performance in contact-separation modes.
• There is a need for advanced MoS₂ architectures to overcome current limitations and enhance TENG efficiency.

Purpose of the Study:

• To report a novel one-step laser-assisted synthesis of hemispherical MoS₂.
• To investigate the potential of hemispherical MoS₂ in noncontact-mode TENGs (NC-TENGs).
• To demonstrate the application of hemispherical MoS₂ in a self-powered image sensor array.

Main Methods:

• One-step laser-assisted synthesis of hemispherical MoS₂ structures.
• Characterization of synthesized hemispherical MoS₂ morphology and distribution.
• Fabrication and testing of NC-TENG devices with flat and hemispherical MoS₂.

Main Results:

• Optimized precursor concentration (0.32 M) yielded uniformly distributed hemispherical MoS₂ with a mean diameter of 234.4 nm.
• Hemispherical MoS₂ significantly enhances electric-field concentration for NC-TENG applications.
• Compared to flat MoS₂, hemispherical MoS₂-based NC-TENGs showed a 22-fold increase in capacitance and a 37-fold increase in open-circuit voltage, extending operational distance to 10 mm.

Conclusions:

• Hemispherical MoS₂ offers a significant advancement over 2D MoS₂ for TENG applications, particularly in noncontact modes.
• The enhanced electric-field concentration and improved performance metrics make hemispherical MoS₂ suitable for high-performance energy harvesting.
• The successful fabrication of a self-powered image sensor array highlights the broad applicability of this novel MoS₂ architecture.