US Perovskite Startups Advance Tandem Solar Manufacturing, Bolstering Domestic Production

While the global solar industry debates the merits of silicon technologies like TOPCon and HJT, the future of high-efficiency photovoltaics is increasingly converging on perovskite-silicon tandem designs. Perovskites, a thin-film material capable of absorbing a broader light spectrum, offer a scalable and cost-effective method to significantly boost solar output when integrated with traditional silicon cells. Chinese solar giant Trinasolar has demonstrated this potential, achieving a record 30.6% efficiency in lab settings and consistently breaking its own records for full-sized modules, recently reaching 840-W output with 27.1% efficiency.

Despite China's aggressive positioning to dominate the perovskite segment, U.S. startups are making significant strides to establish domestic manufacturing capabilities. Scott Graybeal, CEO of California-based Caelux, emphasized the unique opportunity perovskites present for localized production globally. "We have a unique historical moment to reset the manufacturing paradigm internationally," Graybeal stated, highlighting the material's versatility with any silicon solar cell, enabling a more powerful and affordable product.

Two California-based companies, Tandem PV and Caelux, exemplify distinct approaches to commercializing perovskite-silicon tandem technology. Tandem PV, founded by Stanford alumnus Colin Bailie, is developing a full perovskite-silicon tandem solar panel. After a decade of research and $50 million in funding, CEO Scott Wharton announced plans for utility-scale panels by 2026. Tandem PV's mechanically stacked tandem cell has achieved 28% efficiency, with projections to exceed 30% by year-end. Wharton noted strong interest from utility-scale developers, who are keen on acquiring 28%-efficient, U.S.-made panels. The company's strategy focuses on a direct drop-in replacement for existing silicon panels, maintaining size and electronics while significantly boosting performance. Recent investments, including a $4 million grant from the California Energy Commission, are facilitating the build-out of a demonstration factory for larger panels.

Conversely, Caelux, located near Los Angeles, has opted to specialize in perovskite-coated glass, which serves as the front layer for traditional silicon solar panels. The company recently shipped its first commercial order of this 'Active Glass' to an unnamed solar panel manufacturer for a domestic project. Caelux, backed by $24 million in funding, designed its product to seamlessly integrate into existing assembly lines, requiring minimal adjustments. Graybeal explained, "We didn’t want to make it hard for the module manufacturer, because those lines run full-out." Caelux claims its Active Glass can enable up to a 6% efficiency improvement, with the final module performance dependent on the base silicon product. India's Reliance New Energy was an early investor, underscoring global interest in Caelux's model.

Graybeal also noted that the current U.S. solar market headwinds, including potential regulatory rollbacks on incentives like the Investment Tax Credit (ITC), could paradoxically create an opportunity for perovskite technologies. He asserted that perovskites can reduce installation costs by approximately 14% and boost project cash flows by 45% in the U.S., making them highly attractive in a less subsidized environment. Both companies express optimism for the broader perovskite industry, anticipating a long-term transition towards these high-performance thin-film technologies, potentially rivaling crystalline silicon in the future.