Nano-structured M-tcnq Applied Research

Nanotechnology is the dominant trend of science and technology development in 21th century. It is an interdisciplinary which permeated into many fields of the modern science and has a very extensive development perspective. Nanotechnology is base on several modern advanced science and technology. Meanwhile it is promoting the development of advanced scientific and technological progress. Nanotechnology developments also contribute to the development of sensor technology. Sensors base on nanotechnology or nanomaterial have many advantages such as compact, high accuracy, fast responding, low power consumption. Fabrication of nanosensor and related research are becoming a new hotspot.This paper focuses on metal-tetracyanoquinodimethane (M-TCNQ) nanomaterial. Base on the brief introduction of nanomaterial, nanosensor, M-TCNQ, quartz crystal microbalance (QCM) and some other basic notions; the electrical properties of single Cu-TCNQ nanowire were studied. A new approach to enhance the M-TCNQ Field Emission (FE) performance is proposed. A polyethyleneimine (PEI) humidity sensor base on QCM was fabricated. The main contents of this paper were listed as follows:Cu-TCNQ nanowires were prepared by Solution Method. The morphology and structure were characterized via X-ray diffraction (XRD) and scanning electron microscopy (SEM). The electrical switching characteristics of single nanowire were studied. At the threshold voltage (7 V) an abrupt switching occurs from a high-impedance to low-impedance state. Compare to Cu-TCNQ thin film, the single nanowire has similar switching properties.The electrical switching characteristics of single nanowire in low temperature were also studied. The threshold voltage of electrical switching increases as temperature decreases. Negative resistance effect occurs when temperature is below 160 K. Both the heating of a single nanowire caused by an electric current and the external electrical field impact on the switching effect in low temperature.The Field Mission performance of Cu-TCNQ nanowires array and Ag-TCNQ nanowires array were measured respectively. A new approach to increase the M-TCNQ Field Emission (FE) current densities and decrease turn-on electric fields is proposed. Due to the homogeneous-like metal film buffer layer, the Ag-TCNQ turn-on electric field decreases from 9.7 V/μm to 6 V/μm and Cu-TCNQ turn-on electric field decreases from 7.6 V/μm to 2.2 V/μm. And the emission current densities increased by two orders at a field of 8 V/μm. The patterned field emission cathode was then fabricated. The emission luminance was 810 cd/m2 at a field of 8.5 V/μm.A polyethyleneimine (PEI) humidity sensor base on QCM was fabricated. In-situ growth Ag-TCNQ nanowires array was prepared on the surface of QCM probe. The frequency shift is 2000 Hz with increasing relative humidity (RH) from 11% to 95%. The sensor has a response and recovery time of about 30 s and 20 s, respectively, when relative humidity changes suddenly. The results indicate that nano-structure on the probe'surface improves humidity sensitive.The innovations in the dissertation as bellow:(1) The electrical switching characteristics of single Cu-TCNQ nanowire in low temperature were studied for the first time. (2) A new approach to increase the M-TCNQ Field Emission (FE) current densities and decrease turn-on electric fields is proposed. (3) In-situ growth Ag-TCNQ nanowires array was prepared on the surface of QCM probe.