Transparent Piezoelectric Crystal Domain Engineering
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Solution Overview
Problem
Achieving simultaneous high piezoelectricity and perfect transparency in piezoelectric materials has been a long-standing challenge, as existing transparent materials like LiNbO3 and PVDF have low piezoelectric coefficients, while perovskite solid solutions with high piezoelectricity are typically opaque due to light scattering from domain walls.
Innovation Solution
A binary/ternary relaxor-PT based ferroelectric crystal is poled using an AC electric field, reducing the density of 71° domain walls and maintaining high piezoelectricity, with the crystal structure being (Pb1-xMx)[(MI,MII)1-yTiy]O3 or (Pb1-2x/3Mx)[(MI,MII)1-yTiy]O3, where M is a rare earth cation and MI/MII include specific elements, and the crystal thickness ranging from 0.05-5 mm.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If perovskite solid solution ferroelectric ceramics and crystals with high piezoelectricity are used, then piezoelectric coefficients d33 and electromechanical coupling factors k33 are improved, but light transparency deteriorates due to light scattering from domain walls
Solution Approach 1:
The patent applies parameter changes by modifying the domain structure parameters of perovskite solid solution ferroelectrics. Specifically, it transforms the domain configuration from large domains with extensive domain walls to polar nano-regions with domain sizes reduced to hundreds of nanometers to tens of micrometers. This parameter change in domain size eliminates light scattering while preserving high piezoelectricity, resolving the contradiction between transparency and piezoelectric performance
Solution Approach 2:
The patent segments the continuous domain structure into discrete polar nano-regions. By breaking down large domains into smaller polar nano-regions separated by reduced domain wall networks, the material achieves both transparency (through reduced light scattering) and high piezoelectricity (through engineered domain configurations). This segmentation approach directly addresses the technical contradiction
2Illumination intensity
If domain sizes are reduced to polar nano-regions to improve transparency, then light scattering is reduced, but remnant polarization and piezoelectric coefficient d33 deteriorate
Solution Approach 1:
The patent applies parameter changes by optimizing the size, distribution, and orientation of polar nano-regions. Rather than simply reducing domain size, it carefully controls the parameters of polar nano-regions (size: hundreds of nanometers to tens of micrometers, distribution pattern, and orientation) to maintain sufficient remnant polarization while achieving transparency. This controlled parameter optimization resolves the contradiction between transparency and piezoelectric performance
Solution Approach 2:
The patent applies local quality by creating non-uniform domain structures with different characteristics in different regions. The polar nano-regions are engineered with specific local properties (size, orientation, density) that optimize both optical transparency and piezoelectric response locally, while the overall material achieves both global transparency and high piezoelectricity
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The method results in significantly improved transparency while maintaining ultrahigh piezoelectric performance, as demonstrated by increased domain sizes and reduced light scattering, enabling applications in optoacoustic transducers, actuators, and optical-electro-mechanical coupling devices.
Implementation Method 1
A binary/ternary relaxor-PT based ferroelectric crystal is poled using an AC electric field, reducing the density of 71° domain walls and maintaining high piezoelectricity
Implementation Method 2
an object is illuminated with short laser pulses to generate an acoustic wave (namely optoacoustic signals) by means of thermoelastic effect
Implementation Method 3
The signals are then detected by ultrasonic transducers and transformed into images
Data Source
AI summary
A method of preparing a piezoelectric single crystal with high piezoelectricity and near- perfect transparency. The method includes depositing electrodes on two opposition surfaces of a piezoelectric single crystal which is a ferroelectric crystal; AC-poling the piezoelectric single crystal through the electrodes by repeatedly changing polarity of an AC electric field; and after polarization, removing the electrodes on the two opposition surfaces of the piezoelectric single crystal and then depositing Ag nanowire or indium tin oxide (ITO) as electrodes on the two opposition surfaces of the piezoelectric single crystal. Repeatedly changing the polarity of the polarized electric field can increase the domain size of the ferroelectric crystal, or reduce the domain wall density of the domain structure, thereby improving the transparency of the piezoelectric single crystal having high piezoelectric.