Chemically modulated graphene quantum dot for tuning the photoluminescence as novel sensory probe.

Eunhee Hwang,Sora Bak,Hanleem Lee,Hee Min Hwang,Hyoyoung Lee,Junghee Yang,Yeoheung Yoon,Yonghun Shin

doi:10.1038/srep39448

Eunhee Hwang, Sora Bak + Show 6 more

Open Access

https://doi.org/10.1038/srep39448

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Abstract

A band gap tuning of environmental-friendly graphene quantum dot (GQD) becomes a keen interest for novel applications such as photoluminescence (PL) sensor. Here, for tuning the band gap of GQD, a hexafluorohydroxypropanyl benzene (HFHPB) group acted as a receptor of a chemical warfare agent was chemically attached on the GQD via the diazonium coupling reaction of HFHPB diazonium salt, providing new HFHPB-GQD material. With a help of the electron withdrawing HFHPB group, the energy band gap of the HFHPB-GQD was widened and its PL decay life time decreased. As designed, after addition of dimethyl methyl phosphonate (DMMP), the PL intensity of HFHPB-GQD sensor sharply increased up to approximately 200% through a hydrogen bond with DMMP. The fast response and short recovery time was proven by quartz crystal microbalance (QCM) analysis. This HFHPB-GQD sensor shows highly sensitive to DMMP in comparison with GQD sensor without HFHPB and graphene. In addition, the HFHPB-GQD sensor showed high selectivity only to the phosphonate functional group among many other analytes and also stable enough for real device applications. Thus, the tuning of the band gap of the photoluminescent GQDs may open up new promising strategies for the molecular detection of target substrates.

Highlights

A band gap tuning of environmental-friendly graphene quantum dot (GQD) becomes a keen interest for novel applications such as photoluminescence (PL) sensor
To protect from insertion of nitrogen and other additional oxygen functional groups before adding the grafted molecules, we synthesized bare GQDs using a solvothermal method with ethanol to obtain a clean and intrinsic GQD8
Observation of the morphology and thickness of the hexafluorohydroxypropanyl benzene (HFHPB)-GQDs and bare GQDs were conducted by atomic force microscopy (AFM)

Summary

Introduction

A band gap tuning of environmental-friendly graphene quantum dot (GQD) becomes a keen interest for novel applications such as photoluminescence (PL) sensor. As the growing hazard of chemical attacks in our society grows, a detection of toxic materials still has been widely studied in sensor technology[1]. This technology has improved the quality of life and has contributed to novel applications such as health monitoring, environmental monitoring, and safety. Yasaei et al studied the sensing properties of chemically untreated graphene at the grain boundaries[5] They proved that the grain boundaries are highly sensitive sites for catching phosphonates by sequentially checking the numbers of graphene grain boundaries. These reasons, the development of novel sensing materials with facile processing, fast response and a dual checking system to reduce misdiagnoses is urgently required in sensor applications. It is strongly believed that the HFHPB moiety shows an advanced property on interaction with organophosphorus DMMP compound

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