Perovskite-silicon tandem cells by LONGi: status and timeline

Perovskite-silicon tandem cells

Perovskite-silicon tandem cells stack perovskite atop silicon to capture broader spectrum. Reached 35.5% efficiency (ESTI-certified July 2026), the world record.

ResearchStage 1 of 5

World record at 35.5% efficiency certified July 2026; lab-stage development, not yet in production.

Updated Jul 2026Checked 10 Oct0 updates this week

Milestones

Next · Path to pilot production

LONGi perovskite-silicon tandem reaches 31.8% efficiency2023Complete.
Efficiency improved to 35.5%, certified by ESTIJul 2026Complete.
Path to pilot productionTarget 2027Not yet reached.

Most important updates

LONGi perovskite-silicon tandem solar cell sets world efficiency record at 35.5%, certified by ESTIJul 2026

Upcoming

2027Path to pilot production (next)

Current obstacles

Perovskite durability under field conditionsDegrade under moisture, oxygen, UV. Lab samples last months; need 25+ years in field. No proven scalable encapsulation.
Lab-to-production scalingMoving lab cells to module-size (1-2 m²) and factory speed requires major capital, new equipment, unproven yield curves.

Physics limits

Theoretical efficiency ceilingShockley-Queisser limit is ~43%; at 35.5% already near practical bounds, further gains small.
Encapsulation cost burden25-year durability requires expensive barrier films, edge sealing. Cost may not be recovered in bulk commodity solar, limiting tandem to premium applications.

How it works

2 parts

Light capture

Two junctions broaden spectrum

Perovskite captures high-energy photons; passes rest to silicon for low-energy capture. Broader spectrum = higher efficiency.

Manufacturing challenge

Encapsulation and scalability

Perovskite must resist moisture, oxygen, heat. Production is slow; coating on silicon substrates needs new factories.

Spec sheet

Spec	Perovskite-silicon tandem cells
Certified efficiency (July 2026)	35.5%^R (reported)
Certification body	European Solar Test Installation (ESTI)^R (reported)

^R reported by the company

Update log

1 update

Jul 2026

Major: LONGi perovskite-silicon tandem solar cell sets world efficiency record at 35.5%, certified by ESTIPressTest

About LONGi

The team behind Perovskite-silicon tandem cells

LONGi

Solar cells, modules, perovskite, silicon, HIBC back-contact

LONGi is the world's largest solar module manufacturer. It leads in silicon wafer production and developing next-gen perovskite-silicon tandem and back-contact solar cells. Founded in 2000 and rebranded in 2017 after acquiring LERRI Solar.

World records: perovskite-silicon tandem at 35.5% (ESTI-certified July 2026) and HIBC silicon at 28.13%.
Operates world's largest wafer capacity; manufactures at gigawatt-scale across Chinese plants.
Vertically integrated from polysilicon refining to modules, maintaining cost leadership in commodity solar.

longi.com (opens longi.com)Company profile →

Founded: 200026 yrs
Headquarters: China
Status: Public
Valuation: public
Works in: EnergySolar
Coverage: 2 programs · 2 updateslatest 1 Jul 2026checked 10 Oct
People: Li Zhenguo (opens en.wikipedia.org)Founder and President

Spec

Perovskite-silicon tandem cells

Certified efficiency (July 2026)

35.5%^R (reported)

Certification body

European Solar Test Installation (ESTI)^R (reported)