# Silicon-vacancy color centers in Si- and Si,P-doped nanodiamonds: thermal susceptibilities of photo luminescence band at 740 nm

## TL;DR

This study investigates how the spectral properties of silicon-vacancy centers in doped nanodiamonds change with temperature, highlighting doping effects and implications for biological thermometry.

## Contribution

It provides the first detailed analysis of thermal susceptibilities of SiV centers in Si- and Si,P-doped nanodiamonds over biologically relevant temperatures.

## Key findings

- Si-doped nanodiamonds show linear spectral shifts with temperature.
- Si,P-doped nanodiamonds exhibit reduced susceptibilities.
- Laser-induced heating may be intrinsic due to high SiV concentration.

## Abstract

We have characterized thermal susceptibilities of the spectral band at 740 nm of silicon-vacancy (SiV) centers in Si- and Si,P-doped nanodiamonds over a temperature range from 295 K to 350 K, which is of interest for thermometry in biological systems. Si-doped crystals reveal linear dependence of the SiV zero-phonon line position, width and relative amplitude with susceptibilities of 0.0126(4) nm/K, 0.062(2) nm/K and $-0.037(2)$ K$^{-1}$, respectively. Si,P-doped nanodiamonds show significantly smaller (up to 35 % for the width) susceptibilities and prove control of SiV properties with additional chemical doping. It is argued that a significant contribution to the heating of the nanodiamonds induced by laser light can be intrinsic due to a high concentration and low luminescence quantum yield of SiV centers.