Photovoltaic Tunneling Layer for Ion Migration Control
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Solution Overview
Problem
Photovoltaic (PV) module stability and reliability are compromised due to material migration and electrical shunting issues, particularly with ions from the substrate affecting the absorber layer, leading to performance degradation and sensitivity to moisture.
Innovation Solution
Incorporating a tunneling layer, typically an ultra-thin dielectric layer composed of materials like silicon oxide or tantalum pentoxide, between the TCO stack and the semiconductor window layer to act as a physical barrier against particle migration while maintaining electrical transparency, thereby preventing unwanted electrical contacts and preserving interfacial chemistry.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the window layer is thinned to increase light transmission and photoconversion efficiency, then efficiency is improved, but electrical shunting and shorting between the absorber layer and TCO stack can occur, compromising stability
Solution Approach 1:
A tunneling layer is introduced as an intermediary between the TCO stack and the window layer/absorber layer. This ultra-thin dielectric layer (typically 1-10 nm) acts as a mediator that simultaneously allows electrical tunneling for current flow and provides physical barrier properties to prevent ion migration and material interdiffusion, thereby resolving the contradiction between efficiency and stability
Solution Approach 2:
The patent changes the thickness parameter of the dielectric layer to an ultra-thin range (1-10 nm) and controls its electrical properties through material selection and deposition conditions. This parameter change enables the layer to exhibit dual functionality: electrical transparency for tunneling current while maintaining physical barrier properties against ion migration
2Reliability
If a dielectric layer is added to prevent electrical contact between layers, then electrical stability is improved, but resistance increases due to the energy barrier
Solution Approach 1:
The thickness of the dielectric layer is reduced to an ultra-thin range (1-10 nm), which changes the electrical transport mechanism from classical blocking to quantum mechanical tunneling. At these thicknesses, the energy barrier is still present physically but electrons can tunnel through it, maintaining low electrical resistance while preserving the physical barrier function
Solution Approach 2:
The patent replaces the classical mechanical barrier concept with quantum mechanical tunneling. Instead of relying on a thick dielectric barrier that blocks electrons, the system uses a ultra-thin layer where quantum tunneling dominates, substituting the classical electron-blocking mechanism with a quantum tunneling mechanism that allows current flow
3Productivity
If the window layer is made thinner to allow more light transmission, then efficiency is improved, but manufacturing precision becomes more critical to prevent missing portions and direct contact
Solution Approach 1:
The tunneling layer is deposited beforehand as a cushioning layer between the TCO stack and the window layer. This pre-deposited ultra-thin dielectric layer provides a buffer that compensates for potential gaps or discontinuities in the thinned window layer, preventing direct contact between the TCO and absorber layer even when manufacturing variations occur
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 tunneling layer enhances the stability and reliability of PV modules by reducing ion migration, preventing electrical shunting, and allowing for thinner window layers, which increases efficiency by allowing more light to reach the absorber layer without compromising electrical performance.
Implementation Method 1
tunneling refers to a quantum mechanical phenomenon where a sub-atomic particle, e.g., an electron, tunnels through a barrier, e.g., a classically forbidden energy state, that it classically could not surmount
Implementation Method 2
Such a tunneling layer provides a physical barrier to particles, but not an electrical barrier to sub-atomic electrons and electrical current
Implementation Method 3
there is quantum-mechanically a finite probability of this transition through the dielectric layer
Implementation Method 4
electrons do not need to overcome an energy barrier to pass the tunneling layer
Implementation Method 5
it is possible for the materials of some layers within the module to migrate to other layers within the PV module under the influence of the electrical current caused by photoconversion
Data Source
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AI summary
A photovoltaic module including a dielectric tunneling layer and methods of forming a photovoltaic module with a dielectric tunneling layer.