Preparation And Properties Of Octadecyltrichlorosilane Self-assembled Multilayer Films

In order to solve collision relaxation problem of the polarized atoms in atomic vapor chamber,the preparation and research of anti-relaxation coatings have attracted wide attention.As a high temperature effective?170°C?anti-relaxation material,octadecyltrichlorosilane?OTS?has good anti-relaxation property and can effectively maintain polarization state of atoms.The formation mechanism and optimum preparation condition of OTS coatings have yet to be studied.In addition,it exists difficulty in introducing OTS films into miniaturized chambers.In this paper,OTS self-assembled multilayer films were prepared by immersion method on glass substrates.And the mechanism of film formation was studied by atomic force analysis.By changing coating time and solution concentration,the surface morphology and performance of OTS films were studied.In addition,the patterned OTS films,prepared by photolithography,were introduced into miniaturized atomic vapor chambers,combined with standard MEMS process.BiFeO₃?BFO?films were prepared by the OTS hydrophobic template,and the effects of the number of spin coating layers on the morphology and property of BFO films were investigated here.The OTS film,prepared by evaporation deposition method,was used as interface modification layer so as to study the effects on photovoltaic properties of BFO thin films.The main research contents are as follows:?1?Experiments show that,the formation of a complete OTS coating was in accordance with the typical nucleation growth mechanism.By studying the effect of immersion time and solution concentration on the surface morphology and hydrophobicity of OTS self-assembled films,self-assembled films with good hydrophobicity and high coverage were prepared at the concentration of 5 mM and 15min immersion time,with water droplet contact angle as high as 116.4°.?2?In this study,OTS anti-relaxation coatings were successfully applied in MEMS micro-chambers with the combination of photolithography,reactive ion etching?RIE?and anodic bonding technology.At last,the chamber?3×3×0.5 mm³?was well sealed and its leakage rate was as low as 1.27×10^-8 Pa·m³/s.?3?A patterned OTS self-assembled film was prepared on surface of FTO conductive glass by immersion method,photolithography and reactive ion etching?RIE?technique.In this paper,BFO films were successfully induced by spin coating method and one-time annealing process onto surfaces of OTS self-assembled film templates.By studying the effect of number of coating layers?4,6,8 and 10 layers?on the surface morphology and ferroelectric properties of BFO films,we find that:When coated with6 layers,the patterned BFO film have better crystallinity structure,better polarization,good ferroelectric properties and less film defects.?4?The photovoltaic performance of BFO thin film solar cells modified with reduced graphene?RGO?layer and OTS film was studied.It was found that:the open circuit voltage?Voc?of BFO film modified with OTS was improved obviously;while RGO was more helpful to improve the fill factor?FF?and photoelectric conversion efficiency?PCE?of the battery structure.