# Enhanced Photoelectrochemical Performance of 2D Bi2O3/TiO2 Heterostructure Film by Bi2S3 Surface Modification and Broadband Photodetector Application

## TL;DR

A new 2D Bi2S3/Bi2O3/TiO2 film improves photoelectrochemical performance and works well as a broadband photodetector.

## Contribution

The novel Bi2S3 surface modification enhances the performance of Bi2O3/TiO2 heterostructures for photoelectrochemical devices.

## Key findings

- The device has an on/off current ratio of 1.3 × 10^6 at 0 V bias.
- It achieves a detectivity of 5.7 × 10^13 Jones at 0.8 V bias.
- The film degrades pollutants with 97.7% efficiency in 60 minutes.

## Abstract

Photoelectrochemical devices have garnered extensive research attention in the field of smart and multifunctional photoelectronics, owing to their lightweight nature, eco-friendliness, and cost-effective manufacturing processes. In this work, Bi2S3/Bi2O3/TiO2 heterojunction film was successfully fabricated and functioned as the photoelectrode of photoelectrochemical devices. The designed Bi2S3/Bi2O3/TiO2 photoelectrochemical photodetector possesses a broad light detection spectrum ranging from 400 to 900 nm and impressive self-powered characteristics. At 0 V bias, the device exhibits an on/off current ratio of approximately 1.3 × 106. It achieves a commendable detectivity of 5.7 × 1013 Jones as subjected to a 0.8 V bias potential, outperforming both bare TiO2 and Bi2O3/TiO2 photoelectrochemical devices. Moreover, the Bi2S3/Bi2O3/TiO2 photoelectrode film shows great promise in pollutant decomposition, achieving nearly 97.7% degradation efficiency within 60 min. The appropriate band energy alignment and the presence of an internal electric field at the interface of the Bi2S3/Bi2O3/TiO2 film serve as a potent driving force for the separation and transport of photogenerated carriers. These findings suggest that the Bi2S3/Bi2O3/TiO2 heterojunction film could be a viable candidate as a photoelectrode material for the development of high-performance photoelectrochemical optoelectronic devices.