Theoretical-Experimental Molecular Engineering to Develop Nanodevices for Sensing Science



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Molecular electrostatic potentials (MEPs) and vibrational electronics (?vibronics?) have developed into novel scenarios proposed by our group to process information at the molecular level. They along with the traditional current-voltage scenario can be used to design and develop molecular devices for the next generation electronics. Control and communication features of these scenarios strongly help in the production of ?smart? devices able to take decisions and act autonomously in aggressive environments. In sensor science, the ultimate detector of an agent molecule is another molecule that can respond quickly and selectively among several agents. The purpose of this project is the design and development of molecular sensors based on the MEPs and vibronics scenarios to feature two different and distinguishable states of conductance, including a nano-micro interface to address and interconnect the output from the molecular world to standard micro-technologies. In this dissertation, theoretical calculations of the electrical properties such as the electron transport on molecular junctions are performed for the components of the sensor system. Proofs of concept experiments complement our analysis, which includes an electrical characterization of the devices and measurement of conductance states that may be useful for the sensing mechanism. In order to focus this work within the very broad array between nanoelectronic and molecular electronics, we define the new field of Molecular Engineering, which will have the mission to design molecular and atomistic devices and set them into useful systems. Our molecular engineering approach begins with a search for an optimum fit material to achieve the proposed goals; our published results suggest graphene as the best material to read signals from molecules, amplify the communication between molecular scenarios, and develop sensors of molecular agents with high sensitivity and selectivity. Specifically, this is possible in the case of sensors, thanks to the graphene atomic cross section (morphology), plasmonic surface (delocalized charge) and exceptional mechanical and electrical properties. Deliverables from this work are molecular devices and amplifiers able to read information encoded and processed at the molecular level and to amplify those signals to levels compatible with standard microelectronics. This design of molecular devices is a primordial step in the development of devices at the nanometer scale, which promises the next generation of sensors of chemical and biological agents molecularly sensitive, selective and intelligent.