Flexible Piezoelectric Structure via Chemical Etching of Sacrificial Substrate
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Solution Overview
Problem
Current methods for fabricating flexible piezoelectric structures are complex, costly, and difficult to scale industrially due to the need for expensive materials like Sapphire and precise optical systems, limiting the choice of materials and scalability of energy harvesting devices like mechanoelectrical microgenerators.
Innovation Solution
A chemical process is used to transfer the piezoelectric material to a flexible polymer substrate, forming structural layers on a metallic sacrificial substrate, which is then etched to obtain a flexible piezoelectric structure, allowing for a simple and low-cost method suitable for industrial-scale production, with a polymeric adhesion and support layer ensuring adhesion and elasticity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If laser lift-off process is used to transfer piezoelectric layer to flexible substrate, then piezoelectric structure can be obtained, but fabrication complexity and cost increase significantly
Solution Approach 1:
The patent extracts the piezoelectric layer from the sapphire substrate using chemical etching of a sacrificial layer, eliminating the need for complex laser lift-off equipment and processes while achieving the same transfer function
Solution Approach 2:
The patent replaces the optical/mechanical laser lift-off system with a chemical etching process using sacrificial layers, substituting complex physical systems with simpler chemical reactions to achieve layer transfer
2Reliability
If sapphire substrate and laser lift-off system are used, then piezoelectric layer transfer is achieved, but manufacturing cost increases
Solution Approach 1:
The patent uses inexpensive sacrificial layers (metallic or oxide) that are deliberately designed to be removed after serving their temporary purpose of supporting piezoelectric layer deposition, replacing expensive sapphire substrates and laser equipment
Solution Approach 2:
The patent changes the approach from physical/optical parameters (laser wavelength, power) to chemical parameters (etching solution composition, temperature, time), enabling cost-effective manufacturing with standard chemical equipment
3Reliability
If laser lift-off process is implemented, then piezoelectric structure fabrication is possible, but industrial scalability is limited
Solution Approach 1:
The patent segments the fabrication process into distinct chemical steps (deposition on sacrificial layer, etching, transfer) that can be independently optimized and scaled, unlike the integrated laser process which is difficult to parallelize
Solution Approach 2:
The patent replaces the laser lift-off mechanical/optical system with chemical etching processes that can be performed in batch or continuous mode using standard chemical processing equipment, enabling industrial-scale production
4Reliability
If laser lift-off method is used, then flexible piezoelectric structure is obtained, but material selection is limited
Solution Approach 1:
The patent creates a universal sacrificial layer approach that can support various piezoelectric materials (PZT, PMN-PT, Pb(Mg3Nb2/3)O3-PbTiO3) and can be removed by different etching methods, enabling broad material selection unlike laser lift-off which is material-specific
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
This method enables the production of a flexible piezoelectric structure that is cost-effective, scalable, and suitable for energy harvesting devices, improving mechanoelectrical energy conversion efficiency and enabling the use of a wider range of materials, such as Lead Zirconate Titanate, for high energy conversion efficiency.
Implementation Method 1
Piezoelectric materials are promising materials for electromechanical energy conversion technologies. These materials become electrically polarized when subjected to a mechanical stress. In other words, a mechanical stress applied to the piezoelectric material causes an electrical signal by piezoelectric effect.
Implementation Method 2
The metallic sacrificial substrate is then etched by a chemical etching process
Data Source
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AI summary
The invention relates to method for obtaining an elastically-flexible piezoelectric structure (150), characterized in that it comprises steps of: - depositing a piezoelectric thin layer (110) on a chemical etching sensitive metallic sacrificial substrate (100); - depositing an elastically-flexible polymeric support layer (130) on the piezoelectric thin layer, - selectively and chemically etching said metallic sacrificial substrate to obtain an elastically-flexible piezoelectric structure comprising the piezoelectric thin layer and the elastically-flexible polymeric support layer used as permanent substrate (140) of said structure.