This thesis proposal presents a series of studies which explores the use of single wall carbon nanotubes (SWNT) as a light absorber in VO2 photo-thermal actuators. The recent strong interest in VO2 among applied researchers has been driven by the drastic and reversible changes in the properties of this smart material, such as electrical resistivity and optical transmissivity, across its phase transition. This phase transition, also called insulator-to-metal transition (IMT), occurs at a temperature of about 68 oC and spans about 5 oC, which is highly hysteretic and temperature-dependent. Although this temperature range is close to room temperature, it still represents a considerable power burden for practical transducer applications, especially for photo-thermal actuators. Current efforts to reduce the transition temperature in VO2 thin films involve doping or growing pre-stressed films. Nevertheless, the aforementioned approaches have great limitations due to either reduced material property change across the phase transition or requirement of specific substrates, respectively. Rather than compromising the advantages of VO2, this paper proposes a new method based on a SWNT VO2 hybrid structure that utilizes the strong optical absorbance of SWNT. The devices allow more efficient triggering of the phase transition in VO2 by light irradiation. The chirality dependent optical property of SWNT also enables a simple solution for wavelength selective micro-actuator and allows exploration of new applications based on photo-thermal actuation.
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