Study On Novel Plasmonic Sensors Employed For Ultrasensitive Biosensing

Surface plasmon resonance?SPR?technology based on the metal film,known as real-time monitoring,no damage and sensitivity,has become a simple and direct sensor detection method both in monitoring and recording the level of biochemical molecules.In addition,the surface plasmon wave?SPW?excited by Kretschmann structure based on prism/noble metal film is very sensitive to the local refractive index change of the sensing medium.When SPW interacts with the tiny refractive index change of sensing interface,the reflection curve characteristics of Kretschmann structure also change obviously.However,with the development of detection field towards ultra-low concentration?<1×10^-1212 M?and small molecular biological analytes?DNA bases,cytokines,etc.?,the traditional SPR sensing structure cannot be able to achieve stable detection.The sensor based on prism precious metal film structure only has low detection sensitivity and the noble metal sensing interface with poor biocompatibility cannot capture bio-molecules with small molecular weight.Herein,this paper focuses on improving the detection performance?Sensitivity,detection accuracy,etc.?of the traditional SPR biosensors.To date,the superior electronic and optical properties of novel two-dimensional materials have been widely employed in designing various optoelectronic devices,energy storages and SPR sensors.Remarkably,the SPR biosensor structures enhanced by graphene,TMDCs,MXenes,Black phosphorus,hexagonal boron nitride and other two-dimensional materials have aroused great enthusiasm of many researchers.In this paper,the study background of this thesis is two-dimensional material enhanced plasmonic resonance,and through phase modulation to improving detection performance of the traditional SPR biosensor.In addition,the resonance principle and characteristics of the SPR sensor are studied using plasmonic resonance theory,Fano resonance principle and the principle of thin film optical transmission matrix.Moreover,we propose the SPR sensing structure which can detect bio-molecules in an ultra-low concentration.Finally,through theoretical calculation and simulation modeling,the detection performance of the plasmonic sensor model is analyzed.In this thesis,two kinds of SPR biosensor models based on two-dimensional material sensitization are designed for ultra-low concentration bio-analysis.The main research work is as follows:?1?A deep ultraviolet SPR sensor based on aluminum-graphene hybrid structure is proposed in this thesis in detail.This paper introduces the photoelectric properties of graphene nanometer layers,describes the role of graphene in enhanced SPR.It can be found that,our proposed the phase detection sensitivity based on the deep ultraviolet SPR sensor is 5.44 times higher than that without graphene,and 5 orders of magnitude more than the angle detection sensitivity.In addition,by changing the thickness of aluminum and graphene,the designed deep ultraviolet SPR biosensor can detect organic solution?1,1,1,3,3-hexafluoro-2-propanol solution,HFIP?and gas molecules?NH₃,NO₂?.We believe that the proposed deep ultraviolet SPR sensor is expected to be a novel gas and biochemical detection sensor in deep ultraviolet region.?2?A novel Fano resonance with two-dimensional material is proposed to enhance the sensitivity of SPR biosensor.This paper elaborates the Fano resonance mechanism,and describes the superiority of the Fano enhanced SPR biosensor compared with the surface plasmon resonance enhanced SPR sensor.We proposed the 2D-SPR sensor model with silver-silica-h-BN heterostructure,and introduce the role of h-BN in this model.The results show that,the proposed Fano enhancement in phase detection is¹00 times more sensitive than the traditional phase detection sensitivity based on SPR biosensor,overcoming the weak limitations of the traditional SPR biosensor detection signal.In particular,this SPR biosensor can control the coupling degree by changing the thickness of h-BN.The novelty of this article:?1?This article proposed a multi-functional ultra-high sensitivity SPR sensor in the deep ultraviolet region,which can provide an important reference value for the study of deep ultraviolet region sensor.?2?This paper designed a Fano enhanced high-sensitivity 2D-SPR biochemical sensor,which can provide an important reference for the development of SPR biochemical sensor with both ultra-high sensitivity and detection accuracy.