# Writing DNA Bases into sp3 Quantum Defects

## TL;DR

This paper shows how DNA bases can be used to create quantum defects in carbon nanotubes for single-photon emission at room temperature.

## Contribution

A new method is introduced to translate DNA sequences into semiconductor defect properties using in situ diazotization.

## Key findings

- Adenine, cytosine, and guanine create distinct optical signatures in carbon nanotubes.
- Thymine acts as a chemically inert spacer in the process.
- DNA templating reduces reaction randomness and improves defect uniformity.

## Abstract

Quantum defects in carbon nanotubes create deep exciton traps that enable room-temperature single-photon emission, while DNA encodes molecular information with unparalleled programmability. A general chemical framework capable of directly translating biological sequence information into semiconductor defect energetics, however, has remained elusive. Here, we demonstrate that native DNA bases can be written into organic color centers in single-walled carbon nanotubes through in situ diazotization of nucleobases within DNA-wrapped scaffolds. The primary aromatic amines of adenine, cytosine, and guanine are selectively activated to generate covalent sp3 defects with distinct, nucleobase-specific optical signatures, whereas thymine remains chemically inert and functions as a programmable spacer. DNA templating confines reactive intermediates, suppressing the stochasticity of small-molecule diazonium chemistry and enabling uniform defect incorporation. Spectroscopy and theory reveal that emission energies are governed by nucleobase identity rather than defect density. By encoding nucleobase identity into the energetic landscape of semiconductor defects through in situ diazotization, this work establishes a direct chemical bridge between molecular sequence and quantum photonics.