How the First Practical Silicon Solar Cell Works
A 1954 invention by Bell Labs researchers that created the first silicon-based solar cell capable of converting sunlight into enough electricity to power everyday devices.
Original patent title: “Solar energy converting apparatus”
A 1954 invention by Bell Labs researchers that created the first silicon-based solar cell capable of converting sunlight into enough electricity to power everyday devices. Granted to Bell Telephone Laboratories Inc in 1957 with 2 claims and 59 forward citations, and it is now in the public domain.
Key facts
Coverage
What does this patent actually cover?
This patent describes a device that uses a silicon body to turn sunlight into electrical current to charge a battery. It creates a p-n junction by placing a thin p-type zone, doped with boron, next to an n-type zone. The p-type zone is kept thin—specifically, about the same thickness as the distance electrons can travel before recombining—to ensure electricity is generated efficiently. It also includes a one-way electrical gate, known as a unilaterally-conductive element, to ensure power flows from the solar cell to the battery but prevents the battery from draining back through the cell at night.
The gap
What does this patent NOT cover?
- Does not cover solar cells made from materials other than silicon.
- Does not cover solar power systems that lack a battery for energy storage.
- Does not cover the use of non-boron impurities for creating the p-type zone.
- Does not cover solar cells without the specific one-way electrical gate (diode) for preventing battery discharge.
These exclusions are unique to PatentBrief — derived from the actual claim language, not patent-office boilerplate.
What made this novel
The inventors realized that by carefully controlling the thickness of the p-type layer to match the electron diffusion length, they could maximize the number of electrons collected before they were lost, drastically increasing efficiency.
The Patent Drawing
Schematic visualization of the patent's claim structure. Hand-drawn diagrams in progress for each landmark patent.
Where you've seen this
Real-world examples
Early space satellite power systems
Modern silicon-based rooftop solar panels
Solar-powered calculators
Off-grid remote power stations
Why it matters
The bigger picture
This is the foundational patent for modern photovoltaics. Before this, solar cells were made of selenium and were far too inefficient for practical use. This invention proved that silicon could generate enough power to run electronics, eventually leading to the global solar energy industry.
Filed
March 5, 1954
Granted
February 5, 1957
Market context
Who's building on this
Companies in this space
Companies like First Solar, SunPower, and JinkoSolar continue to refine the p-n junction physics established here. While the original Bell Labs patent has long expired, the fundamental architecture of the silicon solar cell remains the industry standard.
Market impact
This patent triggered the transition from theoretical solar research to a viable commercial power source. It enabled the space race by providing a reliable power source for satellites and laid the groundwork for the multi-billion dollar renewable energy market we see today.
Claim 1 — Plain English
What this patent covers
This patent describes a device that uses a silicon body to turn sunlight into electrical current to charge a battery. It creates a p-n junction by placing a thin p-type zone, doped with boron, next to an n-type zone. The p-type zone is kept thin—specifically, about the same thickness as the distance electrons can travel before recombining—to ensure electricity is generated efficiently. It also includes a one-way electrical gate, known as a unilaterally-conductive element, to ensure power flows from the solar cell to the battery but prevents the battery from draining back through the cell at night.
The clever bit
The inventors realized that by carefully controlling the thickness of the p-type layer to match the electron diffusion length, they could maximize the number of electrons collected before they were lost, drastically increasing efficiency.
What it does not cover
- Does not cover solar cells made from materials other than silicon.
- Does not cover solar power systems that lack a battery for energy storage.
- Does not cover the use of non-boron impurities for creating the p-type zone.
- Does not cover solar cells without the specific one-way electrical gate (diode) for preventing battery discharge.
Patent Journey
From filing to expiry
PatentBrief Score
Impact Score
Early stage
Citation count
35/40
Highly cited
Claim breadth
1/20
Narrow claimsclaimsThe numbered statements at the end of a patent that legally define what the inventor owns.Read more →
Recency
0/20
Older than 20 years
Assignee scale
0/20
Independent or smaller assigneeassigneeThe entity that owns the patent — usually the inventor's employer or a company.Read more →
PatentBrief Impact Score — based on citation count, claim breadth, recency, and assignee scale. Not a legal assessment.
Heuristic Value Estimate
What this patent might be worth
$30K – $97K
Midpoint $60K · expired or expiring · industry ×1.4
Heuristic only — blends forward/backward citation counts, claim scope, time remaining, litigation history, and CPC-derived industry baseline. Real valuations need a professional appraisal.
The original legal language
Original claims
2 claims as filed with the patent office.
Concepts involved
Citations
Patent lineage
Cite this patent
Chapin, D. M., Fuller, C. S., & Pearson, G. L. (1957). How the First Practical Silicon Solar Cell Works (U.S. Patent No. 2,780,765). U.S. Patent and Trademark Office. https://patentbrief.org/patent/us/2780765/solar-cell-photovoltaic
Auto-generated from the patent record. Double-check author order and the issue date against the official USPTO document before submitting.
Embed
Add this patent to your site
Drop this plain-English patent card into any blog post or article — free, no signup. It always links back to the full breakdown here.
<div data-patentlens-widget data-patent-number="US2780765"></div> <script src="https://patentbrief.org/embed.js" async></script>
Stay in the loop
Get a weekly digest of new patents.
One email per week. No spam. Unsubscribe anytime.
Keep exploring
Related patents you should know
US 4683195 · 1987
How to Make Billions of Copies of a DNA Segment
This patent describes the Polymerase Chain Reaction (PCR), a method to rapidly create many copies of a specific piece of DNA or RNA, enabling its detection and analysis.
Cetus Corp
US 8697359 · 2014
How to Edit Genes in Human Cells Using an Engineered CRISPR System
This patent describes an engineered CRISPR-Cas9 system for precisely cutting DNA in eukaryotic cells to change how genes work, opening the door for gene editing in complex organisms.
Massachusetts Institute of Technology
US 7657849 · 2010
How the iPhone's Slide-to-Unlock Gesture Works
Apple's 2010 patent describes unlocking a device by dragging a specific graphical image across the touchscreen along a predefined path, a gesture that became iconic with the original iPhone.
Apple Inc
US 4733665 · 1988
How Doctors Implant a Permanent Stent Using a Balloon
This patent describes the method for placing a permanent, expandable wire mesh tube inside a blood vessel or other body tube using a balloon-tipped catheter to widen it and keep it open.
Expandable Grafts Partnership
US 4405829 · 1983
How RSA Public-Key Encryption Keeps Digital Messages Secret
This patent describes the foundational RSA algorithm, a method for securely sending messages where anyone can encrypt a message using a public key, but only the intended recipient can decrypt it using a secret private key.
Massachusetts Institute of Technology
US 4575330 · 1986
How 3D Printers Build Objects Layer by Layer from Liquid
This patent describes the foundational method for 3D printing, where a machine builds a three-dimensional object layer by layer by hardening a liquid material with light or other energy.
UVP Inc
Semantically similar
You might also find these interesting
US 4064521 · 1977 · RCA Corp
How Amorphous Silicon Changed Solar Power
US 2569347 · 1951 · Bell Telephone Laboratories Inc
The Invention of the Junction Transistor
US 3102230 · 1963 · Bell Telephone Laboratories Inc
The Invention of the Modern Field-Effect Transistor
US 2524035 · 1950 · Bell Telephone Laboratories Inc
The Invention of the Transistor
More to explore
More in Energy & Clean Tech
US 2708656 · 1955
How the First Nuclear Reactor Works
US 223898 · 1880
How Thomas Edison Invented the Practical Incandescent Light Bulb
US 2742437 · 1956 · Oxy Catalyst Inc
How Eugene Houdry Invented the Modern Catalytic Converter
US 3723796 · 1973
How a Single Coil Powers Multiple Motor Armatures Simultaneously
New to patents?
Common Questions
Frequently Asked Questions
What does How the First Practical Silicon Solar Cell Works cover?
A 1954 invention by Bell Labs researchers that created the first silicon-based solar cell capable of converting sunlight into enough electricity to power everyday devices.
Who owns patent US 2780765?
Bell Telephone Laboratories Inc owns this patent, granted in 1957.
When does this patent expire?
This patent has expired and is now in the public domain — anyone can use the invention freely.
What is patent US 2780765 cited by?
This patent has been cited by 59 later patents that build on its ideas.
What problem does this patent solve?
This is the foundational patent for modern photovoltaics. Before this, solar cells were made of selenium and were far too inefficient for practical use. This invention proved that silicon could generate enough power to run electronics, eventually leading to the global solar energy industry.
What does this patent NOT cover?
Does not cover solar cells made from materials other than silicon.
Same assignee
More from Bell Telephone Laboratories Inc
Patent monitoring