First-Principles Nonequilibrium Green's Function Approach to Energy Conversion in Nanoscale Optoelectronics.

Area of Science:

• Quantum mechanics
• Nanoscale optoelectronics
• Computational physics

Background:

• Photon-electron conversion is key for nano-optoelectronics.
• Accurate modeling of nanoscale devices is challenging.
• Existing methods may not fully capture complex interactions.

Purpose of the Study:

• To develop a quantum-mechanical method for modeling energy conversion in nanoscale optoelectronic devices.
• To study photoinduced charge transport and electroluminescence.
• To provide a practical theoretical framework for device design.

Main Methods:

• Utilized the nonequilibrium Green's function (NEGF) formalism.
• Investigated electroluminescence in a two-level model with inelastic scattering treatments.
• Applied density-functional tight-binding (DFTB) for single-molecule junctions.
• Modeled a graphene/graphite-C3N4 heterojunction photovoltaic device.

Main Results:

• Demonstrated the importance of electron-photon self-consistency in inelastic scattering.
• Achieved excellent agreement between predicted and experimental emission spectra for single-molecule junctions.
• Showcased the impact of atomistic details on the photoresponse of nanostructured devices.

Conclusions:

• The developed NEGF-based method offers a practical approach for modeling realistic nanodevices.
• This framework enables accurate simulation of optoelectronic processes at the nanoscale.
• The study facilitates the design and optimization of future nano-optoelectronic technologies.