【作者】 李佳；

【导师】 张健；

【作者基本信息】 华东师范大学 ， 微电子学与固体电子学， 2019， 硕士

【摘要】 近年来,随着对柔性电子设备需求的不断增加,高性能柔性传感器引起了学界的广泛关注,但目前的传感器仍无法兼顾高灵敏度和高柔性。为此,需要开发特有的新型材料制备及加工技术。聚合物金属化在柔性电子的应用中最为广泛,引起了诸多关注。本工作围绕低温溶液法制备银/聚酰胺酸(poly(amic acid),PAA)复合结构展开,基于差分进化算法的反向传播神经网络模型(Back Propagation neural network based on Differential Evolution,DE-BPNN)优化工艺参数,实现了高阻态和高导态的可控制备,研究了材料的电学和机械特性,并探索了复合结构在柔性传感中的应用,实现了高灵敏度和宽应变范围的统一。论文主要内容如下:1、基于表面改性和离子交换技术,实现PAA表面金属银层的原位生长,获得了Ag/PAA复合结构。通过DE-BPNN优化工艺参数,实现了高阻态和高导态复合结构的可控制备。选取PAA浓度,硝酸银(Ag NO3)离子交换时间,硼氢化钠(Na BH4)浓度和还原时间4个工艺参数作为DE-BPNN模型的输入信息,Ag/PAA方块电阻和总工艺时间的乘积作为输出信息。选择1077组工艺参数作为学习样本,建立了DE-BPNN的工艺参数模型,得到优化的高阻态和高导态复合材料的生长条件;另外选择49组工艺参数作为测试样本,进行模型准确度预测,相对误差小于1.96%。结果表明,所建立的DE-BPNN模型可以得到全局性的工艺参数最优解。2、依据所建立的DE-BPNN模型,研究了Ag/PAA复合结构的柔性传感特性,分别制备电阻型应变式传感器和电容型压力式传感器阵列。利用高阻态Ag/PAA复合结构作为应变敏感材料,高导态Ag/PAA复合结构作为导电电极,进行了传感特性研究。结果表明,高阻态Ag/PAA复合结构所制备应变式传感器灵敏度是10.96,应变范围1%~9%,可以承受8000次弯曲应力测试,比未经模型优化的材料具有更好的稳定性;高导态Ag/PAA复合结构满足电极材料的要求,所制备的电容型阵列传感器可实时测量压力值变化。3、采用低温溶液化学退火的方法,改善表面金属层存在的缺陷,进一步升Ag/PAA复合结构性能。选择不同浓度的卤素盐溶液,通过浸泡处理,利用卤素盐对银纳米粒子(Ag NPs)融合改善表面金属银层的缺陷。结果表明,在高导态的Ag/PAA复合结构中,1wt%Na I溶液化学退火50s,可以使得表面方块电阻下降18.2%;而对于高阻态的Ag/PAA复合结构,化学退火对电阻的影响作用不明显。更多还原

【Abstract】 In recent years,with the increasing demand for flexible electronic devices,highperformance flexible sensors have attracted widespread attention.However,these sensors still cannot achieve high sensitivity and high flexibility simultaneously.To this point,it is necessary to develop unique new material preparation and processing technologies.Polymer metallization used widely in flexible electronics has attracted much attention.In this work,the composite structure of silver/poly(amic acid)(PAA)was prepared by low temperature solution method.The back propagation neural network model based on differential evolution algorithm(DE-BPNN)was used to optimize the process parameters to achieve either high resistance or high conductivity.The optimized process parameters are obtained,and the electrical and mechanical properties of the material are studied.The application of this composite structure in flexible sensor is explored to achieve high sensitivity and wide strain range.The main content of this thesis is as the following:1.Based on surface modification and ion exchange technology,the in-situ growth of the metal silver layer on the surface of PAA is realized,and the Ag/PAA composite structure is obtained.With the DE-BPNN optimized process parameters,the controllable preparation of high-resistance or high-conductivity composite structures was achieved.Four process parameters such as PAA concentration,Ag NO3 ion exchange time,Na BH4 concentration and reduction time were selected as the input of DE-BPNN,and the product of Ag/PAA sheet resistance and total process time was used as the output.1077 sets of process parameters were selected as learning samples.The DE-BPNN model was established,and the optimized growth conditions of high-resistance and highconductivity composites were obtained.Another 49 sets of process parameters were selected as test samples to evaluate the model accuracy.The results indicated that the obtained relative error is no more than 1.96%.The results implied that the established DE-BPNN model can provide the global optimal solution of process parameters.2.According to the established DE-BPNN model,the flexible sensing characteristics of the Ag/PAA composite structure were studied,and the resistive strain sensor and the capacitive pressure sensor array were prepared,respectively.The high-resistance Ag/PAA composite structure was used as the strain-sensitive material,and the high-conductivity Ag/PAA composite structure was used as the conductive electrode.The results show that the strain sensor with high-resistance Ag/PAA composite structure has the maximum gauge factor of 7.49 and the maximum strain range of 1% to 9%.It can withstand 8000 bending stress tests without degradation.All these showed that the optimized sensor has better stability than the one with materials without model optimization.The lowresistance Ag/PAA composite structure satisfies the requirements of the electrode.And the prepared capacitive array sensor can measure the pressure value change in real time.3.The low temperature solution chemical annealing method is used to improve the defects of the surface metal layer and further improve the performance of the Ag/PAA composite structure.With the selected halogen salt solution,the defects of the surface metal silver layer were improved by the immersion treatment,in which silver nano particles(Ag NPs)can be melted by the halogen salt.The results showed that in the high-conductivity Ag/PAA composite structure,the chemical annealing of 1wt% Na I solution for 50 s can reduce the surface sheet resistance by 18.2%.For the high-resistance Ag/PAA composite structure,the effect of chemical annealing on electrical resistance is not obvious.更多还原