# Elucidating the Influence of Sodium Fluoride on the Structural and Photoelectrochemical Properties of Antimony Sulfide Thin Films

## TL;DR

This study shows how adding sodium fluoride improves the performance of antimony sulfide thin films in splitting water using sunlight.

## Contribution

The novel contribution is demonstrating that NaF doping enhances structural and photoelectrochemical properties of Sb2S3.

## Key findings

- NaF doping reduces surface roughness and modifies the morphology of Sb2S3 thin films.
- Photocurrent density increases from 0.48 to 0.52 mA cm–2 with NaF doping.
- Carrier concentration rises significantly from 9.24 × 10¹⁵ to 3.47 × 10¹⁸ cm–3 under illumination.

## Abstract

Photoelectrocatalysis has become a sustainable and eco-friendly
method for water splitting, enabling the production of hydrogen and
oxygen using solar energy. Among various photoabsorber materials,
antimony sulfide (Sb2S3) is regarded as a promising
candidate for photoelectrochemical (PEC) water splitting due to its
suitable band gap (∼1.7 eV), high optical absorption coefficient,
and the earth-abundant nature of its elements. However, its practical
application is limited by deep-level defects that can cause charge
carrier recombination and reduce PEC efficiency. This work investigates
how sodium fluoride (NaF) doping influences the structural, optical,
and electrochemical properties of Sb2S3 thin
films. NaF doping modifies the surface morphology and decreases surface
roughness. These structural changes are associated with an increase
in photocurrent density from 0.48 to 0.52 mA cm–2 and a significant rise in carrier concentration from 9.24 ×
1015 to 3.47 × 1018 cm–3 under standard illumination. These results demonstrate that NaF
plays a key role in controlling charge transport and improving catalytic
activity. Overall, the findings highlight how dopant-induced modifications
affect the PEC performance of Sb2S3-based photoelectrodes.