Germanium selenide (GeSe) nanosheets are stable and inexpensive and considered to have a great potential for photovoltaic applications, however we have demonstrated that GeSe nanosheets are also promising for sensing technology, in this paper. By spin-coating the GeSe nanosheets on the surface of noble metal (Au), we have obtained a surface plasmon resonance (SPR) sensor with significantly enhanced sensitivity, and the performance of the sensor is closely related to the thickness of the GeSe

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... m. By detecting different refractive index solutions, we have obtained the optimized sensitivity with 3581.2 nm/RIU (which is nearly 80% improvement compared to traditional SPR sensors) and figure of merit with 14.37 RIU−1. Moreover, the proposed SPR sensor was vastly superior in sensing Pb2+ heavy metal ions after coating it with chitosan and GeSe composite. A maximum sensitivity of 30.38 nm/μg/l has been verified, which is nearly six times better than that of conventional SPR sensor. Our results demonstrated that GeSe nanosheets overlayer with modified SPR sensor has its great potential in heavy metal detection and chemical-specific molecular identification.