物理科学与技术学院知识库

水资源在当今社会相当的重要。水不但可以当做原材料制备氢气，也可以利用动能产生电力。在光电催化分解水制备氢气的过程中，其内部载流子分离效率一直是制约光电催化整体效率的重要因素。对于依靠压电效应促进载流子分离率的方法而言，为提高压电效应，铁电或压电材料的电阻往往较高，这不利于光生载流子的分离。为解决这个难题，本文首先考虑了将压电部分放置于电荷收集层之后，使得压电材料的高电阻不影响载流子的分离。作者构建了相应的异质结的理论模型，并通过计算的方法论证了采用不同电荷收集层时，电荷收集层对铁电势的屏蔽效应。作者证明了采用单层石墨烯时，铁电势可以穿过石墨烯并影响光电催化。作者在理论研究的基础之上，进一步通过实验制备了PMN-PT/石墨烯/TiO2的光电催化器件，实验同样证明了PMN-PT的铁电势可以穿过石墨烯，并可以促进二氧化钛的光电催化效率。此外，作者考虑了利用摩擦发电机收集水滴的动能产生电能。该摩擦发电机可以生产电能的同时，检测水滴中氯化钠的含量。与一般的摩擦发电机发电原理不同，该摩擦发电机利用液珠滚落超疏水PDMS层时介电系数的变化发电。

Water sauce is crucial to the development of human society. On one hand, water can be used as raw materials to produce hydrogen. On the other hand, the flowing water can generate electricity. As for photoanode to split water, the low separation rate of photo induced carriers is the main drawback of to increase the overall efficiency. One way to increase the separation rate of carriers is introduce the piezoelectric or ferroelectric material in photoanode. However, high quality piezoelectric material has high intrinsic resistance which would jeopardize the carrier separation. To overcome this problem, Author firstly considers putting piezoelectric material outside the photoanode, and uses Mathematica to calculate the potential distribution in the hetro-structure. The result shows that by using single layer graphene, the Piezopotential can penetrate graphene and further enhance the efficiency of photoelectrochemical catalysis. Based on the calculated result, Author fabricated corresponding device and experimental result confirms our hypothesis. Author also fabricated a new kind of self-powered which can synchronously detect the salinity of water solution from 0 mmol/L to 1 mmol/L and generate electricity. The power generation of self-powered sensor is realized by repeatedly moving water droplets down from hydrophobia PDMS surface to firstly generate negative charges on the surface of PDMS and then change the capacitance between two electrodes to drive the screen charges (electrons) moving back and forth between two electrodes. And the ability for droplet to change the capacitance depends on its salinity.