# Photolithography-Enabled Au/Si Columnar Array Photoelectrochemical Sensor for High-Performance Nitrite Detection

## TL;DR

This paper introduces a new sensor using gold-decorated silicon columns to detect nitrite with high accuracy and reliability.

## Contribution

The study proposes a novel Au/Si columnar array photoelectrochemical sensor for precise nitrite detection.

## Key findings

- The sensor achieved two linear detection ranges with high sensitivities for nitrite.
- It demonstrated excellent selectivity, stability, and successful real-sample detection.
- The detection limit was as low as 0.25 μM under simulated solar irradiation.

## Abstract

In this work, we demonstrate the fabrication of gold-decorated silicon column array (Au/SiCAs) photoanodes for photoelectrochemical (PEC) nitrite detection. The SiCAs were synthesized on n-type silicon substrates via photolithography and anisotropic etching, after which Au nanoparticles were deposited by magnetron sputtering. The Au/SiCAs photoanodes exhibited a pronounced PEC photocurrent response under the simulated solar irradiation. For nitrite determination, the sensor achieved two broad linear ranges (10–500 μM and 2000–10,000 μM) with corresponding sensitivities of 0.25 and 0.33 μA·μM−1·cm−2, along with a detection limit of 0.25 μM (S/N = 3). Moreover, the sensor exhibited excellent selectivity, remarkable stability, and facile fabrication. Successful detection in real sample confirms its potential for practical applications. This study proposes a novel approach for precise and reliable PEC-based nitrite analysis.