Last year, South Korea’s Qcells set the world record for large-area silicon solar cell efficiency, a development that promised to dramatically shrink the size of solar projects and slash costs. Qcells, a subsidiary of South Korea’s giant conglomerate Hanwha Corp, set the world record after achieving 28.6% efficiency by combining a top light-absorbing layer of perovskite with a bottom silicon layer to capture a broader spectrum of sunlight. For some context, high-end commercial solar panels typically operate at 21% to 23% efficiency, meaning they convert about a fifth of the sunlight striking them into usable electricity. More importantly, unlike many high-efficiency records achieved only on lab-scale cells, Qcells’ efficiency was demonstrated on an industry-standard cell designed for mass manufacturing.
But China has now managed to wrestle back the title of the world’s most efficient solar panel maker: leading Chinese solar firm Trina Solar has officially shattered the world record for solar module efficiency, achieving a conversion efficiency of 29.2% and an unprecedented peak power output of 907 watts.
Trina’s solar cell isn’t just any solar cell. Its record was achieved using a perovskite-on-silicon tandem design, which stacks two different solar materials on top of each other to capture a broader range of sunlight. The perovskite layer absorbs higher-energy wavelengths while the silicon layer captures light that would otherwise pass through, allowing the cell to convert more of the sun’s energy into electricity. The company also developed a new interconnection structure between the two layers that reduces energy losses and improves the flow of electrical current through the cell, helping push efficiency to record levels.
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Like Qcells’ earlier record, Trina achieved the breakthrough on industry-standard 210 mm wafers rather than small laboratory cells. The company reported efficiencies of 29.2% on full-size cells and 32.6% on half-cut cells, demonstrating that the technology can be manufactured at commercial dimensions. The resulting module produced 907 watts of power, up sharply from the company’s previous record of 808 watts and well above the output of conventional solar panels currently deployed in the field.
The result pushes perovskite technology further into commercial territory. Researchers have been posting impressive efficiency figures for years; the challenge has been reproducing them on modules large enough to manufacture at scale.
From Microscopic to Groundbreaking-Size
While individual lab cells have reached higher standalone efficiencies on a microscopic level, we are now talking about commercial scale applications.
Conventional silicon panels are nearing the limits of what the technology can deliver. Perovskite-silicon tandem cells offer a way around that by capturing a broader range of sunlight and generating more electricity from the same panel area.
Now, the race is to manufacture them at scale and keep them operating reliably for decades in the field.
Perovskites are a class of materials that share a specific, diamond-like crystal structure. Perovskite solar cells can convert a wider spectrum of sunlight into electricity compared to traditional silicon.
Indeed, perovskites can be layered directly on top of traditional silicon solar cells, with these “tandem” cells absorbing the colors of light that silicon misses and pushing theoretical maximum efficiencies to over 40%. They can be applied in extremely thin layers, allowing them to be sprayed or printed onto flexible films, windows or curved building surfaces.
Further, unlike silicon, which requires high-temperature, energy-intensive manufacturing, perovskites can be processed into inks and printed at room temperature, dramatically lowering production costs. Whereas commercially available perovskite solar cells exist, they are currently not yet widely available for standard residential rooftop installations, in large part because pure perovskite cells degrade rapidly when exposed to outdoor elements like moisture, heat, and UV light.
However, several pioneering companies have started manufacturing and shipping them at scale. This includes California-based Caelux, whose “Active Glass” technology allows factories to build Hybrid-Tandem modules right on their existing assembly lines without redesigned silicon cells or complex overhauls, while UK-based Oxford PV has started shipping modules that boast efficiencies up to 24.5% to utility-scale customers in the U.S. and Europe.
By Alex Kimani for Oilprice.com