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arXiv 2405.09830cond-mat.mtrl-sci
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揭示铁电体中压电-光电子耦合的直接压电效应:第一性原理研究辅助的实验方法

Unveiling the Direct Piezoelectric Effect on Piezo-phototronic Coupling in Ferroelectrics: First Principle Study Assisted Experimental Approach

Koyal Suman Samantaray, Sourabh Kumar, P Maneesha, Dilip Sasmal, Suresh Chandra Baral, B. R. Vaishnavi Krupa, Arup Dasgupta, K Harrabi, A Mekki, Somaditya Sen

AI总结:

本研究以钛酸铋钠为对象,结合实验与第一性原理计算,阐明铁电体中自发极化与压电极化对压电-光电子耦合的作用,揭示纳米纤维因高柔韧性带来更高压电应变系数,从而提升压电-光催化性能的机制。

摘要:

一项新研究探究了自发极化与压电极化在压电-光电子耦合中的不同作用。本研究以关键铁电材料钛酸铋钠(NBT)为对象,聚焦其光催化与压电-光催化性能的差异,旨在明确哪类极化对压电-光电子效应的影响更大。理论评估与实验结果互为补充,提供了更多洞见。\n本研究探究了静电纺丝纳米纤维相较于溶胶-凝胶颗粒在不同光照条件(11W紫外光、250W紫外光及自然太阳光)下提升的压电-光电子性能。在光催化过程中加入超声处理时,静电纺丝纳米纤维的速率常数(k)提升了2.5至3.75倍,而溶胶-凝胶颗粒的性能仅提升1.3至1.4倍。\n采用第一性原理方法的分析显示,纳米纤维的弹性模量(C33)约为溶胶-凝胶颗粒的1/2.15,表明其柔韧性更强。纳米纤维的晶格沿z轴伸长,降低了Bi-O键与Ti-O键的共价性。这些结构差异导致自发极化和压电应力系数(e31与e33)降低。尽管压电应力系数更低,纳米纤维更高的柔韧性使其压电应变系数更高,分别为溶胶-凝胶颗粒的2.66倍和1.97倍,这提升了纳米纤维的压电-光电子耦合性能。

英文摘要:

A new study explores the distinct roles of spontaneous polarization and piezoelectric polarization in piezo-phototronic coupling. This investigation focuses on differences in photocatalytic and piezo-photocatalytic performance using sodium bismuth titanate (NBT), a key ferroelectric material. The research aims to identify which type of polarization has a greater influence on piezo-phototronic effects. A theoretical assessment complements the experimental findings, providing additional insights. This study explores the enhanced piezo-phototronic performance of electrospun nanofibers compared to sol-gel particles under different illumination conditions (11W UV, 250W UV, and natural sunlight). Electrospun nanofibers exhibited a rate constant (k) improvement of 2.5 to 3.75 times, whereas sol-gel particles showed only 1.3 to 1.4 times higher performance when ultrasonication was added to photocatalysis. Analysis using first-principle methods revealed that nanofibers had an elastic modulus (C33) about 2.15 times lower than sol-gel particles, indicating greater flexibility. The elongation of lattice along z-axis in the case of nanofibers reduced the covalency in the Bi-O and Ti-O bonds. These structural differences led to reduced spontaneous polarization and piezoelectric stress coefficients (e31 & e33). Despite having lower piezoelectric stress coefficients, higher flexibility in nanofibers led to a higher piezoelectric strain coefficient, 2.66 and 1.97 times greater than sol-gel particles, respectively. This improved the piezo-phototronic coupling for nanofibers.

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