l'Actualité du Solaire

Scientists present possible innovations for the main photovoltaic cell technologies over the next five years. Given the "urgent need" to deploy photovoltaics on a scale of several terawatts over the next two decies to mitigate greenhouse gas emissions, "innovation in photovoltaic devices takes on a new urgency and impact. "

Even modest advances will have major future impacts on a multi-terawatt scale. They will create ever greater value.

PERC cells will give way to TOPCon technology by 2025. Nevertheless, crystalline silicon photovoltaic cells are approaching the theoretical maximum single-junction efficiency of 29.4%. Research is therefore needed to develop high-temperature selective zone passivation contacts on both sides of the photovoltaic cell.of the photovoltaic cell (also known as 'advanced TOPCon'), in order to improve the transparency and conductivity heterojunction technology (HJT) contacts ('advanced HJT'), and to combine the latest HJT or TOPCon technologies with an interdigitated back contact(IBC) structure, "which could achieve an ultimate practical efficiency of 28% probably as early as 2025".

However, as the theoretical limit is approached, "several new modes of degradation, known as carrier-induced degradation, and metastable defects are revealed", said the researchers.

In addition, the industry is "striving to reduce or eliminate" the use of rare materials such as silver for forming grid lines, and indium used in transparent conductive oxides. Several photovoltaic companies and research laboratories have announced the design of HJT PV cells with reduced indium consumption "or even indium-free HJT cells".

Tandem technology

The development of 2-terminal perovskite/silicon tandem monolithic cells, "considered by many to be the most likely and cost-effective solution", is currently the most active area of research. It has already achieved a record cell efficiency of 33.7% on a cell measuring one square centimetre.

For a 2-terminal tandem cell with 30% efficiency, "the efficiency of the top cell is much more critical than the efficiency of the bottom cell".

"Stability still needs to be improved", say the authors. The degradation of the tandem device should be limited to less than 0.5% per year.

Cadmium telluride

CdTe technology accounts for 25% of large-scale photovoltaic power plants in the United States, but only 5% of the world market. Researchers have spiked a First Solar cell with arsenic. They believe that these Cd(Se,Te) cells doped with a Group V material "will become the main research, development and manufacturing platform."

CIGS

The combination of CIGS (copper, indium, gallium and selenium) in tandem applications is "one of the major areas of future development". CIGS tandem devices "are not limited to combining CIGS with perovskites", as "they can be fabricated with many materials, including CdTe, silicon or CIGS-based alloys with different band gaps".

III-V multijunction

The Americans estimate that these cells can achieve efficiencies of over 45% by using several band gaps, or junctions, each tuned to absorb a specific part of the solar spectrum. III-V photovoltaic cells with multiple junctions could enable "significant spatial energy production", say the authors.

https://www.pv-magazine.com/2023/08/29/pv-cell-technology-trends/

PV Magazine, 30 August 2023

Editor's note It is particularly difficult to predict technological advances. The avenues mentioned are those available today. It is certain that other avenues will emerge within the next twelve months, and that those considered serious will be abandoned by the end of 2024!

The article does have the merit of indicating some interesting current trends.