Cu2O Solar Cell Electrode Stack for Adhesion and Transmittance
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Solution Overview
Problem
Cuprous oxide (Cu2O) solar cells face challenges with low peel strength between the Au film electrode and the Cu2O layer, and cannot produce transmissive solar cells when using Au film electrodes, due to poor adhesion and high resistance issues.
Innovation Solution
A solar cell design incorporating a transparent substrate, a p-electrode structure with a Sn-based metal oxide first p-electrode, a metal or graphene second p-electrode with openings, and an In-based metal oxide third p-electrode, which improves adhesion and transmittance while reducing resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a Au film electrode is used, then low-resistance contact with Cu2O layer is achieved, but peel strength between electrode and Cu2O layer is not high
Solution Approach 1:
The patent employs a composite electrode structure consisting of multiple layers including transparent conductive oxide layers (such as ITO, IZO, or AZO) combined with metal layers (such as Al, Ag, or Mo). This composite structure achieves both low contact resistance through the metal layer and high peel strength through the transparent conductive oxide layer that adheres well to the Cu2O layer, thereby resolving the contradiction between low resistance and high adhesion.
Solution Approach 2:
The transparent conductive oxide layer serves as an intermediary between the Cu2O layer and the metal electrode layer. It provides good adhesion to the Cu2O layer while the metal layer provides low contact resistance, thus mediating between the requirements for strong bonding and low resistance.
2Reliability
If a Au film electrode is used, then low-resistance contact is achieved, but transmissive solar cell cannot be produced
Solution Approach 1:
The patent uses a composite electrode structure where transparent conductive oxide layers (such as ITO, IZO, or AZO) provide both electrical conductivity and optical transparency. These transparent conductive oxide layers replace the opaque Au film while maintaining low contact resistance through combination with metal layers, thereby enabling transmissive solar cell production.
3Productivity
If Cu2O is used for light absorbing layer, then high efficiency is expected, but adhesion with Au film electrode is poor
Solution Approach 1:
The patent employs a composite electrode structure with transparent conductive oxide layers that exhibit excellent adhesion to the Cu2O light absorbing layer. These transparent conductive oxide layers (such as ITO, IZO, or AZO) form strong bonds with Cu2O while providing the necessary electrical conductivity, thereby maintaining high power generation efficiency while solving the adhesion problem.
4Quantity of substance
If Au film electrode is used, then low cost material is available, but peel strength and transmittance are insufficient
Solution Approach 1:
The patent replaces expensive Au film with a composite structure using abundant and inexpensive materials such as transparent conductive oxides (ITO, IZO, AZO) and common metals (Al, Ag, Mo). This composite structure achieves both cost reduction and improved performance in terms of peel strength and transmittance.
Solution Approach 2:
The patent substitutes the expensive Au film with cheaper alternative materials that can be deposited using conventional techniques. The composite electrode structure using transparent conductive oxides and common metals provides comparable or superior performance at lower material cost.
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 design enhances peel strength, maintains high transmittance, and reduces power generation loss by combining Sn-based and In-based metal oxides, enabling efficient and cost-effective solar cell performance.
Implementation Method 1
The Cu2O layer of the Cu2O solar cell forms a low-resistance contact with a high-cost Au film electrode, but when the Au film electrode is used, the peel strength between the Au film electrode and the Cu2O layer is not so high
Implementation Method 2
A transmissive solar cell can be produced by using Cu2O for the light absorbing layer
Implementation Method 3
Cu2O is a wide-gap semiconductor having a bandgap of, for example, 2.1 eV
Data Source
AI summary
A solar cell of an embodiment includes: a transparent substrate; a p-electrode on the substrate, the p-electrode including a first p-electrode containing an Sn-based metal oxide, a second p-electrode having an opening and consisting of a wiring containing a metal or graphene, and a third p-electrode containing an In-based metal oxide; a p-type light absorbing layer in direct contact with a surface of the first p-electrode on a side opposite to the second p-electrode side; an n-type layer provided on the p-type light absorbing layer; and an n-electrode provided on the n-type layer. The third p-electrode is provided to be present between the first p-electrode and the second p-electrode and to be in direct contact with an upper surface of the second p-electrode. An entire side surface of the second p-electrode is in direct contact with the first p-electrode.