# Depth-Dependent Emission from Silver Dopants in Single CdSe Nanoplatelets

## TL;DR

This paper shows how the position of silver dopants in CdSe nanoplatelets affects their light emission, which could be useful for quantum technologies.

## Contribution

The study reveals how dopant depth in nanoplatelets influences emission properties through electrostatic self-interaction effects.

## Key findings

- Dopant emission energy and lifetime depend strongly on their depth within the nanoplatelet.
- Surface dopants emit at lower energies with longer lifetimes, while central dopants emit at higher energies with shorter lifetimes.
- Individual nanoplatelets exhibit two-color emission with high photon antibunching at room temperature.

## Abstract

Dopants in semiconductor nanostructures offer tremendous
control
over electronic, optical, and magnetic properties beyond what is achievable
in bulk materials. We demonstrate that the broad dopant emission in
semiconductor nanoplatelets effectively maps the electron wave function
across the nanoplatelet thickness. Both the emission energy and lifetime
of the dopant transition depend strongly on the depth of the dopant
within the nanoplatelet. This dependence arises from the electrostatic
self-interaction of the charged dopant, which varies with proximity
to the dielectric discontinuity at the nanoplatelet surface. Through
comprehensive single-particle spectroscopy of silver-doped CdSe nanoplatelets,
we verify that acceptors near the center emit at higher energies with
shorter lifetimes, while those near the surface emit at lower energies
with longer lifetimes. This spatial mapping also reveals unusual two-color
emission from individual nanoplatelets, with enhanced Auger recombination
yielding exceptional photon antibunching (>90% purity) at room
temperature,
suggesting potential applications in quantum information technologies.