ANR DARWIN: Boosting the chiral selectivity of nanotube growth by directed evolution

_{ANR DARWIN (2020-2024)}

Major advances have led to a renaissance in carbon nanotubes (CNTs) for the next generation of transistors in microelectronics, which must combine high current density with low energy consumption.

However, these applications require both very high density and purity in semiconductor CNTs, which cannot be achieved simultaneously with current methods.

To meet this dual challenge, the DARWIN project proposes to explore a disruptive approach to directed evolution that exploits small differences in properties between NTCs of different types (metallic or semiconductor) and chiralities, over several cycles of growth-mutation-selection.

The project consists of three stages of increasing difficulty :

• The first stage is to elucidate the influence of NTC chirality on its catalytic growth and etching kinetics using advanced in situ optical imaging methods, atomic resolution MET and numerical simulations.
• The second stage is to test different stimuli to cause changes in chirality along the NTCs during growth, and to statistically study the relationship between final and initial chiralities.
• Finally, the third step is to combine this knowledge to design and optimise directed evolution experiments consisting of multiple growth-mutation-etching cycles, and to quantitatively characterise the effect of these treatments on chirality selectivity and purity in semiconductor NTCs.