A self-powered UV photodetector based on TiO2 nanorod arrays

Yanru Xie,Dong Wang,Lin Wei,Guolei Liu,Yanxue Chen,Jun Jiao,Liangmo Mei,Shishen Yan,Guodong Wei,Qinghao Li

doi:10.1186/1556-276x-8-188

Yanru Xie, Dong Wang + Show 8 more

Open Access

https://doi.org/10.1186/1556-276x-8-188

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Abstract

Large-area vertical rutile TiO2 nanorod arrays (TNAs) were grown on F/SnO2 conductive glass using a hydrothermal method at low temperature. A self-powered ultraviolet (UV) photodetector based on TiO2 nanorod/water solid–liquid heterojunction is designed and fabricated. These nanorods offer an enlarged TiO2/water contact area and a direct pathway for electron transport simultaneously. By connecting this UV photodetector to an ammeter, the intensity of UV light can be quantified using the output short-circuit photocurrent without a power source. A photosensitivity of 0.025 A/W and a quick response time were observed. At the same time, a high photosensitivity in a wide range of wavelength was also demonstrated. This TNA/water UV detector can be a particularly suitable candidate for practical applications for its high photosensitivity, fast response, excellent spectral selectivity, uncomplicated low-cost fabrication process, and environment-friendly feature.

Highlights

Ultraviolet (UV) photodetector has been a popular research issue for its potential applications in a wide range of fields, such as remote control, chemical analysis, water purification, flame detection, early missile plume detection, and secure space-to-space communications [1]
Growth of TiO2 nanorod arrays by hydrothermal process The single-crystalline rutile TNAs used for this study were grown vertically on fluorine-doped tin oxide (FTO) glass using the following hydrothermal methods: a diluted hydrochloric solution was prepared by mixing 50 mL of deionized water with 40 mL of concentrated hydrochloric acid and was stirred at ambient temperature for 5 min, and 400 μL of titanium tetrachloride was added to the mixture
The θ-2θ scan pattern shows that the TiO2 nanorods grown on FTOcoated glass substrates have a tetragonal rutile structure (JCPDS 02–0494)

Summary

Introduction

Ultraviolet (UV) photodetector has been a popular research issue for its potential applications in a wide range of fields, such as remote control, chemical analysis, water purification, flame detection, early missile plume detection, and secure space-to-space communications [1]. Lee et al reported a UV detector based on TiO2/water solid–liquid heterojunction [21] This self-powered UV photodetector behaves similar to a Schottky diode and works in photovoltaic mode. Cao et al reported the photocurrent response of TiO2 nanorod arrays under UV illumination using a 0.5 M Na2SO4 aqueous electrolyte [22], in which TiO2 nanostructures can harvest more incident light photons compared to a flat thin-film active layer because of the markedly enlarged TiO2/electrolyte contact area. They did not report its photosensitivity and spectral response. Further advancements for TiO2-based self-powered UV detectors demand a deeper understanding of the main parameters determining the photoelectric behavior, which requires additional research and insight into the electrical transporting process in these nanostructured devices

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