Scientists build 31%-efficient indium-free tandem perovskite silicon mini-module via reactive plasma deposition

<p>An international research team has fabricated an indium-free perovskite-silicon tandem solar cell using a low-damage reactive plasma deposition (RPD) process.</p>

<p>RPD is a vacuum-based thin-film coating technique in which a plasma generated from oxygen reacts with evaporated metal atoms to form a metal oxide film on the substrate. Unlike conventional sputtering, which bombards the target with high-energy ions that can damage sensitive materials such as perovskites, RPD generates lower-energy particles, allowing dense, conductive oxide films to be deposited with minimal damage to the underlying layers.</p>

<p>Monash University Department of Materials Science and Engineering Adjunct Professor and research co-lead Yuan Cheng said achieving more than 30% efficiency in a commercially relevant tandem mini-module represents an important technical milestone, demonstrating that high performance can be achieved without relying on scarce, high-cost materials.</p>

<p>&#8220;The research team developed a reactive plasma deposition (RPD) process for tin oxide (SnOx) films to serve as the recombination layer, achieving a certified efficiency of 33.6% on a 1 cm² device,&#8221; Cheng said. &#8220;By further extending the application of RPD-SnOx to both the front and rear transparent electrodes, we successfully fabricated indium-free tandem solar cells. We then scaled the technology to a 207.9 cm² mini-module, achieving a certified efficiency of 31.0%.&#8221;</p>

<p>The researchers said the dense and uniform tin oxide films produced by the RPD process provided an improved surface for the self-assembled monolayer used in the device, helping to reduce non-radiative recombination losses and suppress halide ion migration, two mechanisms that can limit solar cell efficiency and long-term stability.</p>

<p>They also explained the devices maintained strong performance after exposure to heat, humidity and more than three months of outdoor operation. &#8220;Indium-free minimodules exhibited high thermal, damp-heat, and outdoor operational stability and retained 65% of their maximum initial efficiency after 105 days of outdoor operation,&#8221; they added.</p>

<p>The results, published in <em><a href="https://www.science.org/doi/10.1126/science.aef5355">Science</a></em>, replace conventional indium-based transparent conducting oxides with tin oxide, an abundant material that the researchers said costs about 1% as much as indium. They said the approach could improve the commercial viability of tandem solar cells by reducing material costs while maintaining high efficiency.</p>

<p>Cheng said the work represents the first demonstration of a large-area, high-efficiency indium-free perovskite-silicon tandem solar cell, indicating that the technology can be scaled beyond laboratory-scale devices.</p>

<p>&#8220;Considering the cost of tin is a mere 1% of that of indium, this breakthrough provides a new materials approach and a viable engineering pathway for low-cost, sustainable and scalable tandem photovoltaics,&#8221; Cheng said. &#8220;Ultimately, this work is of strategic importance for advancing the industrialisation and terawatt-scale deployment of next-generation, ultra-high-efficiency photovoltaic technologies.&#8221;</p>

<p>The research was led by a collaboration involving Monash University in Australia, Soochow University and Chint New Energy Technology Co. Ltd in China, along with other research partners.</p>
<p>The post <a href="https://www.pv-magazine.com/2026/07/17/research-breakthrough-develops-indium-free-tandem-solar-cell-with-31-efficiency/">Scientists build 31%-efficient indium-free tandem perovskite silicon mini-module via reactive plasma deposition</a> appeared first on <a href="https://www.pv-magazine.com">pv magazine Global</a>.</p>