Vapor Deposition Delivers Durable Perovskite-Silicon Tandems

• Breakthrough vapor-deposited perovskite-silicon tandems hit 30% efficiency on textured wafers, surpass 2,000-hour stability—paving mass-production-ready modules as NUS, A*STAR, Trina Solar move to pilot lines.

Researchers at the National University of Singapore, A*STAR and Trina Solar demonstrated the first vapor-deposited perovskite-silicon tandem cells on industrial micrometer-textured wafers, a key step toward mass production. The conformal perovskite growth delivered over 30% power-conversion efficiency and operational stability beyond 2,000 hours, including T90 lifetimes exceeding 1,400 hours at 85°C under 1-sun—among the most durable perovskite-Si tandems reported.

The team solved adsorption and film-formation issues on steep silicon textures by designing a molecule that binds to the wafer surface, enabling uniform perovskite deposition and heat resilience. Next, NUS plans to scale the process to full-size modules and integrate it into pilot manufacturing lines.

How does vapor-deposited perovskite on textured wafers unlock scalable tandem production?

• Preserves silicon’s micro-pyramid texture for light trapping, boosting photocurrent without adding extra patterning steps.
• Conformal coverage over steep features avoids pinholes and edge thinning, cutting shunt pathways and improving yield.
  
• Eliminates the need to planarize wafers, keeping existing texturing lines and consumables in place—true drop-in for c‑Si fabs.
  
• Vacuum co-evaporation enables stoichiometry control across 3D topography, delivering uniform bandgap and thickness at scale.
  
• Surface-binding chemistry seeds nucleation on sharp facets, stabilizing film growth and mitigating de-wetting seen in solution routes.
  
• Low thermal budget fits silicon heterojunction and TOPCon back-end limits, simplifying tandem stack integration.
  
• Inline vacuum clustering links perovskite, charge transport, and TCO deposition, reducing air breaks and contamination risk.
• Dry processing avoids solvent ingress into silicon passivation layers, protecting lifetime and open-circuit voltage.
  
• Maintains pyramid geometry for reduced front-surface reflection, improving angular response and bifacial potential.
• Compatible with standard wafer handling and high-throughput carriers; no special planar substrates or exotic fixtures required
• Better thickness uniformity over texture tightens module power binning, improving factory yield economics.
  
• Scales to large-area wafers more predictably than spin or slot-die on rough surfaces, enabling gigawatt-class tools to run tandems.
  
• Facilitates encapsulation with smoother top TCOs over conformal films, easing mechanical reliability and damp-heat performance.
  
• Reduces interfacial stress concentrations at facet tips versus non-conformal films, improving crack resistance during lamination.
  
• Streamlines quality control via in-situ rate/flux monitoring and end-point metrology, aiding process control and uptime.
  
• Minimizes material waste relative to solution coating, lowering per-watt cost and simplifying lead capture in closed vacuum systems.
• Enables standard pyramid-size freedom (no need to re-optimize texture for wet coating), preserving upstream wafer supplier flexibility.
  
• Improves tandem optical design headroom (e.g., thinner perovskite with same coverage), simplifying current matching across climates.
  
• Supports rapid recipe transfer between lines and sites because vacuum process windows are less sensitive to ambient humidity.
• Opens a path to retrofitting existing Si lines with vacuum perovskite modules, compressing time-to-market for high‑efficiency tandems.