ART-PV reports 29.8% efficiency for a lab tandem cell

In the roughly 5,000 sq ft ISO 7 cleanroom at IIT Bombay’s research park, a solar startup is trying to push beyond silicon’s ceiling. ART-PV India, led by Professor Dinesh Kabra, reports a 29.8% conversion efficiency for a two-terminal monolithic tandem cell combining silicon and CdTe with perovskite.

A standard silicon cell cannot use every wavelength of sunlight equally well; its single-junction efficiency is capped at around 29%, while commercial panels remain several points below that level. ART-PV’s tandem design adds a second layer tuned to absorb what silicon handles poorly. Perovskite is suited to that role because its absorption can be adjusted through its chemistry and it can be deposited at low temperature onto a finished silicon cell.

The architecture is designed to avoid a difficult installation hurdle. “Monolithic” means the layers are grown as one device rather than assembled as separate cells. “Two-terminal” means the result has the same two electrical connections as an ordinary panel, allowing the company to target existing solar systems. ART-PV says the top layer can be placed over crystalline silicon or cadmium telluride thin film. First Solar and Waaree are partners, with preferential licensing rights, according to the company.

The practical consequence is a route to more electricity from the same solar-cell architecture without requiring a new connection format. To test that route beyond individual research cells, India’s Ministry of New and Renewable Energy is funding a pilot manufacturing facility of about $10 million on the IIT Bombay campus. It is intended to produce commercial tandem cells rather than laboratory samples.

That milestone has a hard limit today. The 29.8% figure comes from a laboratory cell, and full-sized modules generally test lower than individual cells. ART-PV has not published a production timeline, module-level efficiency figure or durability result. Perovskite’s sensitivity to heat, moisture and ultraviolet light remains an unresolved problem, so the pilot line is the next test of whether the lab result can survive manufacturing and outdoor use.