# Bright Infrared Colloidal PbS Nanoplatelets with Lead Sulfobromide Shells

## TL;DR

Researchers created bright, stable PbS nanoplatelets with inorganic shells that emit near-infrared light efficiently at room temperature.

## Contribution

A new method to synthesize PbS nanoplatelets with inorganic sulfobromide shells that enhance optical performance and stability.

## Key findings

- The nanoplatelets show a narrow photoluminescence peak of 78 meV at room temperature.
- Inorganic shells reduce surface defects and improve photoluminescence quantum yield.
- The structures are air-stable and suitable for infrared optoelectronics.

## Abstract

We report colloidal
PbS nanoplatelets synthesized in
bromide-containing
media that spontaneously form core/shell heterostructures with inorganic
lead sulfobromide and lead bromide shells surrounding a PbS core.
Band-structure measurements indicate a type-I alignment, which concentrates
electrons and holes within the PbS core. These core–shell nanoplatelets
exhibit near-infrared emission with a remarkably narrow photoluminescence
peak of 78 meV at room temperature. The inorganic shells also act
as robust passivating layers that suppress surface defect states,
yielding an improved photoluminescence quantum yield and preserving
emissive performance under ambient conditions. The resulting nanoplatelets
are bright and air-stable, offering a solution-processable platform
for infrared photonics and optoelectronics, including emitters, detectors,
and integrated photonic components.