Plasmonic Nb₂CT MXene-MAPbI₃ Heterostructure for Self-Powered Visible-NIR Photodiodes

Area of Science:

• Materials Science
• Optoelectronics
• Nanotechnology

Background:

• Two-dimensional (2D) MXenes exhibit surface plasmons for light absorption across visible and infrared (IR) spectra.
• MXenes show potential in optoelectronics but have been limited in IR photodiode applications due to low resistivity and high dark current.
• Developing efficient photosensing materials with broad spectral response and low dark current is crucial for advanced optoelectronic devices.

Purpose of the Study:

• To develop self-powered visible-near-infrared (NIR) photodiodes using heterostructures of methylammonium lead triiodide (MAPbI3) perovskite and niobium carbide (Nb2C T) MXene.
• To leverage the complementary properties of MAPbI3 and Nb2C T MXene for enhanced photodiode performance, including expanded spectral range and suppressed dark current.
• To investigate the charge transfer mechanisms at the MAPbI3/Nb2C T interface responsible for the improved device characteristics.

Main Methods:

• Fabrication of MAPbI3/Nb2C T MXene heterostructures with matched band structures.
• Characterization of photodiode performance under white light and NIR laser illumination (1064 nm).
• Analysis of device performance metrics including responsivity, temporal photoresponse, on/off ratio, and dark current.
• Space-charge-limited current (SCLC) and capacitance measurements to probe charge transfer dynamics.

Main Results:

• The MAPbI3/Nb2C T photodiode exhibited linear response to white light with 0.25 A/W responsivity and <4.5 μs temporal photoresponse.
• Under 1064 nm NIR laser illumination, the photodiode showed a high on/off ratio (∼10^3) and fast response (<30 ms), significantly outperforming Nb2C T-only detectors (<2 s response).
• The enhanced performance is attributed to efficient charge transfer at the MAPbI3/Nb2C T interface, facilitated by coordinate bonding between MXene surface groups and Pb2+ ions.

Conclusions:

• MAPbI3/Nb2C T heterostructures are effective for creating high-performance, self-powered visible-NIR photodiodes.
• The integration of MAPbI3 successfully expands the operational range and mitigates the dark current issues of Nb2C T-based photodetectors.
• The study highlights the importance of interfacial engineering through coordinate bonding for optimizing charge transfer in 2D material-based optoelectronic devices.