MIT Contact Layer for Hybrid Energy Harvesting
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Solution Overview
Problem
Hybrid electrical energy generators face challenges in achieving optimal electrode contact characteristics for both photovoltaic and piezoelectric energy conversion methods, as ohmic contacts are desired for photovoltaic methods while Schottky contacts are needed for piezoelectric methods, and existing solutions do not efficiently adapt to temperature variations.
Innovation Solution
Incorporating a contact layer with metal-insulator transition (MIT) characteristics, such as vanadium oxide, which changes contact characteristics based on temperature, allowing for ohmic contacts at higher temperatures and Schottky contacts at lower temperatures, and using nanowires with piezoelectric materials like zinc oxide, lead zirconate titanate, or polyvinylidene fluoride to form p-n junctions with semiconductor layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single contact layer structure is used, then device complexity is reduced, but adaptability to different energy conversion methods deteriorates
Solution Approach 1:
The contact layer is designed with universal functionality to serve both photovoltaic and piezoelectric energy conversion methods. By using a material with MIT characteristics, a single contact layer structure can provide the appropriate electrical contact characteristics (ohmic or Schottky) required by different energy conversion methods, eliminating the need for separate contact layers for each method.
Solution Approach 2:
The contact layer material exhibits dynamic change in electrical characteristics based on temperature. At lower temperatures, it forms Schottky contact optimal for piezoelectric energy conversion, while at higher temperatures, it transitions to form ohmic contact optimal for photovoltaic energy conversion. This dynamic adaptation allows the same contact layer to serve both energy harvesting methods effectively.
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
Enables efficient conversion of both sunlight and mechanical vibration into electrical energy by dynamically adjusting contact types based on temperature, optimizing energy harvesting across different conditions.
Implementation Method 1
The contact layer includes a material having metal-insulator transition (MIT) characteristics. The contact between the first end of the at least one elongated member containing a piezoelectric material and the contact layer may be an ohmic contact at a temperature above a transition temperature of the material having metal-insulator transition (MIT) characteristics. The contact between the first end of the at least one elongated member containing a piezoelectric material and the contact layer may be a Schottky contact at a temperature below a transition temperature of the material having metal-insulator transition (MIT) characteristics.
Implementation Method 2
A hybrid electrical energy generator may transform sunlight or mechanical vibration into electrical energy according to a surrounding environment. A hybrid electrical energy generator may have a structure in which a photovoltaic element and a piezoelectric element are integrated together, and thus a photovoltaic effect and a piezoelectric effect may occur together or separately.
Implementation Method 3
Solar cells may transform solar energy into electrical energy. When light is directed onto a solar cell, solar cells may generate electrons and holes. The generated electrons and holes may move to an n-type electrode and a p-type electrode respectively, thereby generating electrical energy.
Data Source
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AI summary
According to an example embodiment, an electrical energy generator includes at least one piezoelectric structure, a semiconductor layer and a contact layer. The at least one piezoelectric structure includes a material having piezoelectric characteristics. One surface of each piezoelectric structure forms a p-n junction with the semiconductor layer. The other end of each piezoelectric structure contacts the contact layer that is formed of a material having metal-insulator transition (MIT) characteristics. The piezoelectric structure may be an elongated member, such as a nanowire.