Anisotropic Conductive Back Contact for Thin Film Photovoltaics
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Solution Overview
Problem
Metal electrodes form poor contacts with cadmium telluride in photovoltaic devices, leading to reduced energy conversion efficiency and device deterioration.
Innovation Solution
An anisotropic conductive paste with a polymeric binder and conductive particles is applied to the p-n junction, forming an anisotropic conductive layer that improves adhesion and contact between the cadmium telluride layer and the metal contact layer, facilitating electron flow while isolating individual cells.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If metal electrodes are used as back contact, then device structure is simple, but contact quality with cadmium telluride is poor leading to reduced energy conversion efficiency
Solution Approach 1:
An anisotropic conductive layer is introduced as an intermediary between the metal back contact electrode and the cadmium telluride absorber layer. This intermediate layer improves electrical contact quality and energy collection efficiency without significantly increasing overall device complexity, resolving the contradiction between simple structure and effective energy conversion.
Solution Approach 2:
The back contact structure employs a composite material system consisting of metal electrodes combined with an anisotropic conductive layer containing conductive particles embedded in a polymer matrix. This composite approach enhances the electrical interface between the metal and cadmium telluride, improving energy conversion efficiency while maintaining structural feasibility.
2Duration of action of stationary object
If metal electrodes are used as back contact, then manufacturing process is simple, but device lifetime is reduced due to contact deterioration
Solution Approach 1:
The anisotropic conductive layer serves as a protective intermediary that prevents direct contact between metal electrodes and cadmium telluride, reducing chemical reactions and contact deterioration. This extends device lifetime while the layer can be applied through conventional printing or coating techniques, maintaining reasonable manufacturing simplicity.
Solution Approach 2:
The anisotropic conductive layer is applied beforehand as a protective barrier between the metal back contact and the cadmium telluride absorber layer. This pre-established protective interface prevents harmful chemical interactions and contact degradation over time, extending device lifetime without complicating the manufacturing process.
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 anisotropic conductive layer enhances energy conversion efficiency and device lifetime by providing a reliable conductive back contact that reduces resistance and prevents cell short circuits.
Implementation Method 1
The anisotropic conductive paste includes a polymeric binder and a plurality of conductive particles... providing a reliable conductive back contact that reduces resistance
Implementation Method 2
The anisotropic conductive paste includes a polymeric binder... improves adhesion and contact between the cadmium telluride layer and the metal contact layer
Data Source
AI summary
Thin film photovoltaic devices are generally provided. The device can include a transparent conductive oxide layer on a glass substrate, an n-type thin film layer on the transparent conductive layer, and a p-type thin film layer on the n-type layer. The n-type thin film layer and the p-type thin film layer form a p-n junction. An anisotropic conductive layer is applied on the p-type thin film layer, and includes a polymeric binder and a plurality of conductive particles. A metal contact layer can then be positioned on the anisotropic conductive layer.