Silicon solar cells with hybrid back contacts
Article Date: 12 November 2025
Article URL: https://www.nature.com/articles/s41586-025-09681-w
Article Image: (not provided)
Summary
This Nature paper from Wang et al. describes a hybrid back-contact (HIBC) architecture for crystalline silicon solar cells that combines passivated selective contacts with laser-treated, low-resistivity back contacts. Using a 14-step fabrication flow that includes chemical vapour deposition, patterned laser treatments and passivation stacks, the team produced cells with measured efficiencies around 27.6–27.8%. The work pairs detailed experimental characterisation (lifetimes, contact resistivity, topography, current and surface potential mapping) with COMSOL and TCAD simulations to explain how laser-induced crystallisation of the p-type contact and in-situ edge passivation improve transport and reduce recombination. The research is led by LONGi-affiliated teams with multiple institutional collaborators; LONGi holds the associated IP and many authors are company employees.
Key Points
- The authors demonstrate HIBC silicon solar cells achieving peak efficiencies of approximately 27.8% (reported examples: 27.81% and 27.63%).
- The hybrid approach uses passivating contact stacks together with laser-induced crystallisation to create low-resistivity p-type contacts while retaining surface passivation.
- A 14-step fabrication process is reported, including multiple CVD steps, laser patterning stages and in-situ passivated edge technology (iPET) to limit edge recombination.
- Extensive characterisation (effective lifetime, contact resistivity via TLM, conductive AFM, Kelvin probe mapping) supports the performance claims and identifies loss mechanisms.
- COMSOL and TCAD modelling are used to simulate laser treatment effects, carrier transport and band alignment changes after laser processing.
- Work is industrially oriented: many authors are employed by LONGi, which holds the related intellectual property; funding is from Chinese national and provincial programmes.
Context and relevance
This paper sits at the intersection of heterojunction/passivated-contact advances and manufacturing-friendly processing. It addresses two key industry challenges: keeping contact resistivity low while preserving passivation and doing so with steps (laser patterning, standard CVD/PVD) that are compatible with industrial lines. The efficiency numbers place HIBC among the leading single-junction silicon approaches and the detailed loss analyses and process flow make the work immediately relevant to PV developers aiming for incremental but manufacturable gains.
Why should I read this?
Short version — if you’re tracking where silicon cell efficiencies are headed and want to know which lab tricks could make it into factories, read this. It’s got a practical laser-based twist that keeps passivation AND lowers contact resistance, plus real data and simulations that explain why it works. If you want the technical bits without trawling Nature for hours, this summary has done the heavy lifting for you.