Improving the Thermionic Energy Conversion Efficiency Through Fine-Tuning Functional Characteristics of Multilayer Carbyne-Enriched Nano-Interfaces

Thermionic energy conversion provides a direct method for converting heat into electricity. However, its efficiency has been limited by space charge effects and the absence of optimal emitter materials. We present a groundbreaking approach to improve thermionic emitters by utilizing multilayer thin film nano-interfaces enriched with carbyne, finely tuned to serve as programmable nanodevices. Carbyne, with its linear chain structure, possesses low work functions for emission but has been limited in applications due to its instability. By encapsulating carbyne chains in amorphous carbon nano-matrices through ion-assisted plasma deposition, we successfully synthesized stable electron emitters in the form of 2D-ordered linear-chain carbon. Building on the recent discovery of phonon waves in multilayer nanostructures, we propose the potential to unlock additional functionality in 2D-ordered linear-chain carbon-based interfaces through predictive excitation and tuning of synergistic effects such as self-synchronization of collective atomic vibrations, surface charge mosaic effect, phonon waves propagation and energy-driven nano-patterns. Our approach combines various methods, including energy-driven initiation of allotropic phase transformations, surface acoustic wave-assisted micro/nano-manipulation during ion-assisted pulse-plasma functionalization, heteroatom doping, initiation of directed self-assembly through external electromagnetic fields, and data-driven inverse design approaches. The key aspect of our concept is the use of piezoelectric surface-acoustic waves to induce self-synchronization of collective atomic vibrations in the nano-interfaces of the multilayer thin film for programming emission properties. Furthermore, we incorporate a data-driven approach using the carbon nanomaterial genome derived from neural network-based predictive models, incorporating multiple descriptors to unlock novel functionalities of the nano-interfaces of the multilayer thin film.