Climate and Clean Tech | August 14, 2023

Caelux snags another $12 million to make solar panels more efficient

Amy Cortese
ImpactAlpha Editor

Amy Cortese

ImpactAlpha, Aug. 14 – Solar power costs have dropped by more than 75% since 2010. But the efficiency at which solar panels convert sunlight to energy has only inched up in the past decade, from 15% to 20%.

Pasadena-based Caelux is among a slew of startups looking to use perovskites, a lightweight, flexible crystalline material, to boost the output and cost-effectiveness of silicon-based solar cells. It is leveraging Inflation Reduction Act incentives to build a plant in Baldwin, Calif., outside of Los Angeles, that will coat glass used in solar wafers with the material.

Perovskites capture higher energy blue light, complementing silicon’s lower energy red light absorption. Caelux has seen a 12-15% improvement every time it has doubled its output. “We will enable much higher power output at the same cost per watt,” the company’s Leslie Chang told ImpactAlpha


Caelux has raised $12 million in a third Series A tranche led by Singapore’s Temasek. Khosla Ventures, Mitsui Fudosan, and Fine Structure Ventures also participated, bringing Caelux’s Series A round to $24 million. India’s Reliance New Energy injected $12 million into Caelux last September, and agreed to purchase the first 100 megawatts produced for a solar factory in Gujarat. 

Solar everywhere

Caelux expects to launch its first product, for residential solar panels, by the end of next year and then expand into commercial and utility scale solar. Energy-conducting perovskites can be applied to surfaces from car roofs and window shades to satellites.

“We see perovskites as an accelerant to be able to get everybody to their goals,” said Chang. “It’s thinking about how we can turn all of these different industries into renewable energy vehicles.”