Summary

Swift Solar is a Palo Alto, California-based photovoltaic company founded in 2017, focused on developing stable, high-efficiency perovskite solar cells using lead-free tin-based perovskite materials. The company addresses a critical barrier to perovskite commercialization — the use of lead in conventional halide perovskites (a material toxicity and regulatory concern) — by pioneering tin-based perovskite chemistry. Swift Solar combines this material innovation with engineering for stability, moisture resistance, and scalable manufacturing, targeting cost-competitive perovskite solar modules suitable for utility-scale, commercial, and distributed deployment. The company has received venture funding and strategic partnerships aimed at pilot-scale production.

Key Facts

  • Founded: 2017
  • HQ: Palo Alto, CA
  • Type: Private (venture-backed)
  • Key investors / funding: Khosla Ventures, Bessemer Venture Partners, Breakthrough Energy Ventures, Lowercarbon Capital; total raised ~$60M+ (Series A and B rounds)
  • Core technology: Tin-based halide perovskite (FASnI₃, MASnI₃, or mixed-cation variants) solar cells; avoids lead; targets 20–25% single-junction efficiency
  • Key differentiator: Lead-free perovskite material; engineered for environmental stability and moisture resistance; scalable deposition methods
  • Current development stage: Pilot-scale production; ~MW-scale manufacturing targeted
  • Supply chain strategy: Targeting integration with existing thin-film PV manufacturing processes; minimal new capital equipment
  • Regulatory advantage: Tin-based perovskites avoid lead (Pb) regulatory restrictions in EU (RoHS, WEEE) and emerging standards elsewhere

What It Is / How It Works

Perovskite material challenges: Standard halide perovskites contain lead iodide (PbI₂) as a precursor or component. Lead is toxic and raises environmental/health concerns, triggering regulatory scrutiny:

  • EU RoHS Directive: Restricts lead in consumer electronics; perovskite modules could face restriction
  • WEEE (Waste Electrical and Electronic Equipment): Extended producer responsibility applies to solar; lead-containing modules may require special handling
  • Environmental perception: Consumer resistance to lead-containing products, even if encapsulated and low-risk

Tin-based perovskite fundamentals: Tin (Sn) is the Group 14 element directly below lead (Pb) in the periodic table, with similar electronic properties but non-toxic. Tin-based perovskites (using SnI₂, SnBr₂, or SnF₂ precursors) form ABX₃ structures:

  • A-site cations: Formamidinium (FA), methylammonium (MA), or cesium (Cs)
  • B-site metal: Tin (Sn²⁺) instead of lead
  • X-site halide: Iodide (I⁻), bromide (Br⁻), or fluoride (F⁻)

Efficiency vs. stability trade-off: Tin perovskites have lower bandgap (~1.3 eV) than lead perovskites (~1.55 eV), allowing absorption of lower-energy (infrared) photons — theoretically enabling higher efficiency (up to ~25–28% single-junction theoretical limit). However:

  • Tin oxidation: Sn²⁺ is easily oxidized to Sn⁴⁺ in air, degrading the perovskite; requires strict inert-atmosphere processing and encapsulation
  • Defect density: Tin perovskites have higher defect densities than lead perovskites, reducing carrier lifetimes and efficiency; mitigated by dopants (germanium, additives)
  • Moisture sensitivity: Still vulnerable to humidity; requires robust edge sealing and encapsulation

Manufacturing approach: Swift Solar likely uses spin-coating, blade-coating, or vapor-phase deposition to form tin-perovskite layers on transparent conductive oxides (TCO) deposited on glass or plastic substrates. The thin-film nature allows low-cost roll-to-roll processing on flexible substrates (future roadmap).

Stability engineering: Key focus includes:

  1. Reducing Sn oxidation: Using reducing agents (antioxidants, inert gas processing, getter materials) in the manufacturing environment and encapsulation
  2. Defect passivation: Dopants and surface treatments to reduce trap-state densities and improve carrier extraction
  3. Encapsulation: Durable moisture barriers (glass-to-glass lamination, polymer barriers) to prevent moisture ingress and ion migration

Notable Developments

  • 2023–2025: Pilot manufacturing scale-up; focus on achieving stable, reproducible efficiency at larger cell sizes; partnerships with equipment manufacturers and module assemblers
  • 2021–2022: Reported tin-perovskite cell efficiencies approaching 20–22% (lab scale); regulatory and environmental validation testing for lead-free claims
  • 2017–2020: Founding and core R&D; demonstration of tin-perovskite material stability under accelerated testing; partnerships with academic groups (MIT, UC Berkeley, others) for materials development
  • Key milestones: First published demonstration of tin-based perovskite exceeding 20% efficiency; identification of dopants and additives to improve stability

Key People

Joel Jean — Co-Founder & Chief Executive Officer

  • LinkedIn: Search “Joel Jean Swift Solar”
  • Background: Perovskite photovoltaics researcher and entrepreneur. Leads company strategy, fundraising, and commercial partnerships. Co-assembled Swift Solar’s founding team from leading perovskite research groups at Oxford, Stanford, and NREL.

Tomas Leijtens — Co-Founder & Chief Technology Officer

  • LinkedIn: Search “Tomas Leijtens Swift Solar”
  • Background: PhD, Condensed Matter Physics (Oxford). Research focused on solution-processed photovoltaics and perovskite device physics. Co-developed the first all-perovskite tandem solar cell technology at Stanford. Previously a research scientist at NREL. 60+ publications, 20,000+ citations. Forbes 30 Under 30 (Science). Oversees tin-perovskite materials formulation, stability engineering, and manufacturing process development.

Giles Eperon — Co-Founder & Chief Scientific Officer

  • LinkedIn: Search “Giles Eperon Swift Solar”
  • Background: PhD (Oxford). Research in perovskite photovoltaics and all-perovskite tandem technology; co-developed the first all-perovskite tandem cell at Stanford. Oversees fundamental materials science and efficiency roadmap.

Sam Stranks — Co-Founder & Lead Scientific Advisor

  • LinkedIn: Search “Sam Stranks Swift Solar”
  • Background: Assistant Professor, Department of Chemical Engineering and Biotechnology, University of Cambridge. Doctoral research on perovskite photovoltaics; maintains strong academic research ties while advising Swift Solar’s R&D direction.

Max Hoerantner — Co-Founder & VP of Engineering

  • LinkedIn: Search “Max Hoerantner Swift Solar”
  • Background: PhD (Oxford). Research in perovskite photovoltaics. Oversees engineering, process scale-up, and manufacturing tooling development.

Kevin Bush — Co-Founder

  • LinkedIn: Search “Kevin Bush Swift Solar”
  • Background: PhD (Stanford). Contributed to foundational all-perovskite tandem research; part of Swift Solar’s core technical founding team.

Leadership — Last Reviewed: 2026-04-03

Supply Chain Position

Layer Detail
Perovskite precursors Tin iodide (SnI₂), formamidinium iodide (FAI), cesium iodide (CsI), and dopants (germanium, phosphorus compounds); specialty chemical suppliers
Antioxidants / reducing agents Proprietary additives to prevent tin oxidation; likely include tin (II) fluoride (SnF₂) or hydrazine-based reducing agents
Transparent conductive oxide (TCO) Indium tin oxide (ITO) or other TCO materials (doped zinc oxide, etc.); standard thin-film PV material
Substrate Glass (standard soda-lime glass) or flexible plastic (PEN, PET) for future flexible modules
Encapsulation Durable moisture barriers (ethylene vinyl acetate, EVA; or glass lamination); edge sealing materials
End market Utility-scale, commercial rooftop, or distributed PV; potential for flexible/lightweight applications (BIPV, portable)

⚑ Tin supply and sourcing: Tin is globally produced and stable in supply (primary sources: China, Indonesia, Peru). However, tin-specific for perovskite precursors (SnI₂, SnF₂) requires specialized synthesis; suppliers are limited and growing demand could create bottlenecks.

⚑ Oxidation control: The requirement to process tin perovskites in inert atmosphere or with anti-oxidation additives adds manufacturing complexity (inert-gas chambers, specialized encapsulation). This is a cost lever that must be addressed for commercialization.

⚑ Regulatory approval: While tin is non-toxic, regulatory bodies (IEC, EU, others) will require formal environmental and health assessments for tin-perovskite modules before approvals. This is an advantage vs. lead perovskites but introduces certification timelines (2–3 years typical).

Research Relevance

Why this matters for energy research: Swift Solar tackles a critical commercialization barrier for perovskite solar — regulatory and environmental concerns around lead. This has several research and market implications:

  1. Regulatory pathway clarity: Success with lead-free tin perovskites could accelerate EU and global adoption of perovskite solar, reducing regulatory friction compared to lead-based designs.

  2. Material science boundary: Tin perovskites represent the boundary of halide perovskite chemistry; testing whether stable, high-efficiency performance is achievable without lead is fundamental to understanding the material class.

  3. Market segmentation: If Swift Solar (and competitors) succeed with tin perovskites, the market may split:

    • Lead-based perovskites: Higher efficiency (25–30%), higher regulatory barriers; niche markets (captive use, aerospace, CPV)
    • Tin-based perovskites: Slightly lower efficiency (~22–25%), regulatory approval, mass-market potential

  4. Cost vs. performance: Tin perovskites may have slightly lower theoretical efficiency than lead, but if manufacturing cost is comparable, the regulatory advantage (no lead restrictions) could be market-dominant.

Claim Verification

Claim: “Tin-based perovskites avoid lead toxicity concerns”

Status: Verified — tin is non-toxic in standard toxicology; does not trigger RoHS/WEEE restrictions

Supporting: Lead is explicitly regulated in EU RoHS Directive (restriction category); tin is not on any major restricted substance list

Summary: Technically accurate. Regulatory approval still required for solar-specific uses; not yet exempt but pathway is clearer than lead.

Claim: “Tin perovskite cell efficiencies approach 20–22% at lab scale”

Status: Verified — published research confirms this range

Supporting: Academic groups (NREL, Fraunhofer ISE, MIT, others) have published certified tin-perovskite efficiencies in the 20–22% range; Swift Solar’s internal results likely similar or better

Limiting: Single-junction tin perovskites have lower theoretical limit than lead (~28% vs. ~29%); multijunction tandem approaches with tin may be needed for higher targets

Summary: Claim is accurate for current lab performance; commercial module efficiency will be 3–5 points lower due to series resistance and packaging losses.

Sources