Molybdenum Oxide Interlayer Reduces Contact Resistance in CIGS Solar Cells
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Solution Overview
Problem
CIGS solar cells face reduced overall efficiency due to high contact resistance caused by the molybdenum selenide layer between the back electrode and light absorbing layers, leading to increased series resistance.
Innovation Solution
Incorporating a molybdenum oxide layer between the back electrode and light absorbing layers to reduce contact resistance, which is formed by oxidizing the back electrode or using MoO2 or MoO3, thereby minimizing the generation of contact resistance and lowering series resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a molybdenum selenide layer is formed between the back electrode layer and light absorbing layer to increase adhesive strength, then adhesive strength at the interfacial surface is improved, but contact resistance increases leading to reduced photoelectric conversion efficiency
Solution Approach 1:
A molybdenum oxide layer is introduced as an intermediary layer between the back electrode layer and the light absorbing layer. This mediator layer has lower contact resistance compared to molybdenum selenide while still providing adequate adhesive strength, thus resolving the contradiction between adhesion and electrical conductivity
Solution Approach 2:
The chemical composition of the interface layer is changed from molybdenum selenide to molybdenum oxide, which fundamentally alters the electrical properties (lower resistance) while maintaining mechanical properties (adhesive strength), thereby improving photoelectric conversion efficiency without sacrificing interface bonding
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 molybdenum oxide layer with lower resistance than the contact resistance layer enhances photoelectric conversion efficiency by reducing series resistance, improving the overall performance of the solar cell.
Implementation Method 1
The MoSe2 layer has resistance higher than that of the back electrode layer to increase contact resistance between the window layer and the back electrode layer so that overall efficiency of a solar cell is significantly reduced
Implementation Method 2
Solar cells may be defined as devices for converting light energy into electric energy by using a photovoltaic effect of generating electrons when light is incident onto a P-N junction diode
Data Source
AI summary
Disclosed are a solar cell and preparing method of the same. The solar cell includes a back electrode layer on a support substrate, a molybdenum oxide layer on the back electrode layer, a light absorbing layer on the molybdenum oxide layer, and a front electrode layer on the light absorbing layer.