A new technological breakthrough from China could substantially improve the performance of photovoltaic panels. Researchers have developed an innovative metallization method that enables TOPCon solar cells to exceed 26% efficiency, while remaining compatible with existing industrial infrastructures. This innovation could accelerate the production of more efficient and more competitive solar cells.
The results of this work, published in the scientific journal Matter, are based on a combination of an aluminum-free silver paste and a high-precision laser treatment.
Improving charge transport without damaging the cell
The objective of this new method is to improve the transfer of electric charges while preserving the passivation layers of the solar cell.
These layers play a crucial role in photovoltaic performance, as they help limit energy losses caused by the recombination of electrons and holes before they are collected by the electrodes.
By further protecting these layers while optimizing the metal contacts, researchers have managed to improve the cell’s overall efficiency.
TOPCon technology is gaining ground
Crystalline silicon remains today the dominant technology in the global photovoltaic industry. However, TOPCon cells are rapidly gaining ground among manufacturers.
They offer the advantage of delivering higher efficiencies while remaining compatible with a large portion of the equipment and infrastructures already used in solar cell production plants.
This compatibility is a major asset for the industry, as it allows performance improvements without requiring massive investments in new production lines.
Ultrathin layers to reduce energy losses
TOPCon cells use extremely thin layers designed to limit charge carrier recombination.
Concretely, they prevent some of the electrons and holes generated by sunlight from recombining before reaching the electrodes. A greater amount of solar energy can thus be converted into usable electricity.
Despite these advantages, one obstacle remained until now: the fabrication of very fine metal lines used to collect current at the surface of the cell.
Limitations of conventional methods
Conventional metallization processes generally rely on pastes made from a mixture of silver and aluminum.
After application, these materials are subjected to high-temperature firing to ensure sufficient electrical conductivity. But this thermal step can damage the passivation layers, reducing their ability to effectively retain electrical charges.
It can also lead to the formation of wider metal lines on the surface of the cell. Indeed, these lines obscure part of the surface exposed to sunlight and thus reduce the amount of light that can be converted into electricity.
Aluminum-free silver paste paired with laser
The new approach developed by Chinese researchers is precisely aimed at overcoming these difficulties.
It combines an aluminum-free silver paste with a particularly precise laser treatment. This technique enables an effective electrical contact while reducing the risk of damage to the passivation layers.
By further refining the metal contacts and limiting exposure to temperatures that could damage the cell, this strategy simultaneously improves current collection and light absorption.
Towards higher-performance solar panels
With a conversion efficiency exceeding 26%, this technology could represent a new step in improving TOPCon cells.
Its main industrial appeal also lies in its potential to be integrated into existing manufacturing infrastructures without requiring a complete overhaul of production lines.
This advance could thus contribute to gradually increasing the power delivered by photovoltaic panels while controlling the costs associated with their industrialization.
