Solar Cell Contact Layout With Local Heavy Doping
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Solution Overview
Problem
Current solar cells face challenges in optimizing photoelectric conversion efficiency due to optical and electrical losses, including reflection, non-absorption of long-wave radiation, and electrical recombination at metal-semiconductor contacts.
Innovation Solution
A solar cell design incorporating a substrate with a tunneling dielectric layer and a doped conductive layer featuring heavily doped regions, which reduces contact resistance and enhances current transmission by forming a good ohmic contact with electrodes, thereby improving photoelectric conversion efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a uniform doped conductive layer is used, then the manufacturing process is simple, but the contact resistance with electrodes is high and current transmission is poor
Solution Approach 1:
The patent applies local quality by creating heavily doped regions within the doped conductive layer that have higher doping concentrations than the surrounding areas. These localized heavily doped regions are positioned to contact the electrodes, providing low contact resistance and improved current transmission only where needed, while the rest of the layer maintains its original structure and function.
2Reliability
If the doping concentration is increased throughout the entire layer, then the electrical conductivity improves, but the optical absorption increases and photoelectric conversion efficiency decreases
Solution Approach 1:
The patent resolves this contradiction by concentrating the high doping concentration only in specific heavily doped regions that contact the electrodes, rather than uniformly doping the entire layer. This localized approach provides the necessary electrical conductivity at the contact points while minimizing the overall optical absorption in the doped conductive layer, thereby preserving photoelectric conversion efficiency in the active areas.
3Reliability
If more electrodes are added to improve current collection, then the current transmission improves, but the shadowing effect increases and optical loss increases
Solution Approach 1:
The patent addresses this contradiction by creating localized heavily doped regions that enhance current collection at specific contact points with the electrodes. This allows for effective current transmission through the doped conductive layer without requiring an excessive number of electrodes across the entire cell surface, thereby minimizing the shadowing effect and optical losses while still achieving good current collection.
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 photoelectric conversion efficiency by reducing sheet resistance and contact resistance, allowing for better current conduction and increased light absorption, while also optimizing the doping concentration and depth of the doped conductive layer to minimize optical absorption.
Implementation Method 1
The tunneling oxide structure can provide good surface passivation, thereby reducing composite current caused by metal contact
Implementation Method 2
A doping concentration in the plurality of first heavily doped regions is greater than a doping concentration in other regions of the doped conductive layer
Implementation Method 3
The performance of a solar cell (for example, photoelectric conversion efficiency) is subject to optical and electrical losses
Data Source
AI summary
A solar cell and a photovoltaic module are disclosed, including: a substrate; a tunneling dielectric layer and a doped conductive layer disposed on the substrate, the tunneling dielectric layer being disposed between the doped conductive layer and a surface of the substrate, the doped conductive layer having a N-type or P-type doping element and having a plurality of first heavily doped regions spaced apart from each other and extending in a first direction, a doping concentration in the first heavily doped regions being greater than that in other regions of the doped conductive layer; a passivation layer disposed on a surface of the doped conductive layer facing away from the substrate; and a plurality of electrodes spaced apart from each other, extending in a second direction and penetrating the passivation layer to contact the doped conductive layer, at least two first heavily doped regions contacting a same electrode.