Sub-system
A solar cell's efficiency is decided by how much of the incident light produces collected charge rather than being reflected, transmitted or lost to recombination. Successive cell architectures are successive attacks on those losses, each buying a point or two of efficiency at some cost in process complexity.
In one sentence
Solar cell technology refers to the architecture of the cell — how surfaces are passivated, how contacts are made and where they sit — which determines the efficiency with which sunlight is converted to electricity.
The dominant architecture for years added a rear passivation layer to reduce recombination at the back surface. Its successor inserts an ultra-thin oxide and doped polysilicon layer that lets charge through while blocking recombination, gaining efficiency for a manageable number of extra process steps — which is why it became the mainstream choice.
Heterojunction cells combine crystalline silicon with thin amorphous layers, achieving high efficiency and excellent temperature behaviour at the cost of a different process line and more silver. Back-contact cells move all contacts to the rear so no metal shades the front, gaining efficiency with the most complex processing of the four.
At a silicon surface the crystal ends abruptly, leaving unsatisfied bonds that trap charge carriers and destroy them before they can be collected. Passivation layers satisfy those bonds chemically or repel carriers electrically. Nearly every efficiency gain of the past fifteen years has come from doing this better at one surface or another.
Cells are contacted with screen-printed silver paste, and silver is a material cost that does not fall with scale. Reducing consumption per cell, or replacing silver with copper plating, is a live area of development — and solar's share of global silver demand has grown enough to matter to that market.
A cell that collects light on both faces gains energy from ground reflection, which can add a meaningful percentage over a year depending on the surface beneath. It changes mounting design and pairs naturally with trackers, and it is now standard on utility-scale projects for that reason.
1 of these is marked as a chokepoint: a handful of qualified suppliers, a multi-year lead time, or a single geography.
A material cost that does not scale away and ties module cost to a precious metal market.
Each architecture requires a specific set of tools; changing architecture means re-equipping a line.
Deposition and etchThe substrate every crystalline architecture starts from.
Polysilicon and wafersSilane, the dopant gases and the etchants behind every passivation step come from the same industrial gas suppliers the chip industry draws on.
Specialty gasesOther pages in this map that name Cell technology as something they cannot do without.
What each company supplies at this step, and — where a public figure exists — its share of this specific market — with what that share measures, the period it covers and who published it. Some rows also show the company’s own reported revenue for the segment covering this step, which is a different thing: it says how much this business matters to that company, not how much of the market it holds. Not a ranking and not a recommendation.
Manufactures cadmium telluride thin-film modules rather than crystalline silicon cells.
Major crystalline cell and module manufacturer.
Supplies deposition and process equipment used in cell manufacturing.
Manufactures modules and develops solar projects.
Produces polysilicon and solar cells at large scale.
largest producer by capacity; the four largest Chinese producers held 65% between them global polysilicon market2024 · PV Tech
Whether heterojunction or back-contact architectures take share from the current mainstream.
Whether silver consumption per cell falls materially or is replaced by copper.
Whether efficiency gains keep arriving at a pace that justifies re-equipping lines.
Each page explains one technology in plain language, states what it depends on, and names companies by what they supply at that step. Company roles are described qualitatively and deliberately carry no market shares, revenue figures or rankings — those change faster than an explainer can, and a stale number is worse than none. Ticker links point at company pages on this site and are provided for reference only.
Nothing here is investment advice, a recommendation, or a forecast. A company named on a page about a technology is not thereby a good investment, and the chokepoints described are structural facts about supply chains rather than predictions about prices. Technology moves; where a page describes something as unresolved or in development, that was true when it was written.