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Tandem solar cells are widely viewed as a path to cheaper, more powerful solar electricity.
Photo Credit: iStock
A team of researchers in China appears to have cleared a major hurdle for next-generation solar power, pushing a tandem solar cell to 34% efficiency in the lab while also showing strong durability.
According to Interesting Engineering, scientists at Soochow University and LONGi Central R&D Institute built the device, and independent certification measured its open-circuit voltage at 2.014 volts — one of the highest readings reported for this kind of cell.
Clean-energy researchers have been watching perovskite-silicon tandem cells closely because they pair a perovskite top layer with a conventional silicon base, a setup that can capture more solar energy than standard silicon-only panels.
A big obstacle has been achieving strong performance at scale. Textured silicon surfaces are excellent for trapping light, but their uneven structure makes it harder to create smooth, high-quality perovskite films, and charge can also be lost at a buried interface inside the cell, reducing both efficiency and voltage.
Instead of using a flat insulating layer, the team placed ultra-thin monoclinic zirconia nanoparticles at the interface to manage that trade-off. 
“Second, the discrete nanoparticles form nanoscale localized contacts at the interface. The zirconia regions provide field-effect passivation that suppresses non-radiative recombination, while the exposed monolayer pathways preserve efficient hole extraction,” the researchers explained in a press release.
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In testing, the device reached a laboratory power conversion efficiency of 34.0%. Its steady-state efficiency was certified at 33.5%, and its open-circuit voltage was independently verified at 2.014 volts.
Tandem solar cells are widely viewed as a path to cheaper, more powerful solar electricity. If manufacturers can extract more energy from each panel, homes, businesses, and utilities could generate more power from the same roof or plot of land.
What makes this advance stand out is that earlier efforts to improve the buried interface often fixed one problem while worsening another: They reduced charge losses but also made it more difficult for electricity to move through the device.
The team also reported signs of improved longevity. After 2,000 hours of continuous simulated sunlight at room temperature, encapsulated cells still retained 84% of their initial efficiency. Time-resolved measurements found charge carriers lasting nearly twice as long, increasing from 1.46 to 2.81 microseconds.
Professor Jiang Liu, Prof. Xiaohong Zhang, and Dr. Hongbo Mo co-led the research at Soochow University, along with Dr. Bo He at LONGi Central R&D Institute. Huimin Zhang and Qingshui Zheng contributed equally as first authors.
At the nanoscale, the design used a speckled zirconia scaffold to help the perovskite spread more evenly, produce larger crystal grains, and stay better anchored through strong chemical bonding. Zirconia’s high dielectric properties also helped shield the device from electrical fluctuations and charge buildup.
While this remains a laboratory result rather than a product on store shelves, it points to a practical route for making tandem solar panels more efficient and durable.
“The results show that a carefully patterned insulating interface can improve perovskite film growth and suppress recombination without blocking charge extraction. This nanoscale interface design provides a practical strategy for developing more efficient and durable perovskite/silicon tandem solar cells,” the press release concluded.
These stories explore tandem and perovskite solar cells, from efficiency records to new ways of improving performance.
• In Germany, scientists completed a years-long tandem solar project that could reshape the energy industry.
• Researchers built an antimony-selenide tandem cell that reached 20% efficiency and widened material options.
• In Singapore, engineers achieved certified world-record efficiency with a redesigned perovskite solar cell.
• Scientists unveiled a selenium-based performance boost that could make solar panels more effective.
• Researchers developed a pulse-shaped light treatment to lift solar-cell output and energy generation.
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