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This study aims to investigate the effect of the Sn2+-substituted into the CuFeO2delafossite on thermoelectric properties in the Sn content of x = 0.03, 0.05. The CuFe1−xSnxO2samples were synthesized by solid state reaction. The crystal structure was characterized by XRD, TGA, XPS and the thermoelectric properties were measured in the range of 300 to 960 K. The Seebeck coefficient display positive sign in all temperature range and the XPS show the stable Sn+2state as confirming the Sn-doped CuFeO2playing p-type conductor. The Sn2+-substituted supports the mixed valency Fe3+/Fe4+state in transition octahedral oxide of FeO6layer enhancing Seebeck coefficient. The high Seebeck are appeared in content of x=0.03 which are 280 to 340 µV/K in the range of 300 to 800 K. The experimental Seebeck corresponds to the prediction formula at high temperature. Totally, the maximum Power Factor is 2.30×10−4W/mK2occurring in the CuFe0.95Sn0.05O2at 860 K which is higher than that value of the undoped-CuFeO2in 4 times. These support that the Sn-substituted CuFeO2delafossite enhancing thermoelectric properties.

We have performed a quartz crystal microbalance (QCM) study of the uptake and nanotribology of organophosphate (tricresylphosphate (TCP) and t-butyl phenyl phosphate (TBPP)) layers adsorbed from the vapor phase onto amorphous and polycrystalline silicon and octadecyltrichlorosilane (OTS) treated silicon substrates. The materials were selected for their relevance to MEMS applications. About 3-5 monolayer-thick organophosphate films are observed to form readily on both silicon and OTStreated silicon. The coatings moreover exhibit mobility in the form of interfacial slippage or viscoelasticity in response to the oscillatory motion of the QCM, implying that enhanced tribological performance may be expected in MEMS applications.

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