# [TECH] Solar Cells (Photovoltaics)

**Solar Cells** convert sunlight directly into electricity via the photovoltaic effect, and have become the cheapest source of electricity in history as of 2020.

## Overview

Becquerel discovered the photovoltaic effect (1839). Bell Labs produced the first practical silicon solar cell (1954, Chapin, Fuller, Pearson; 6% efficiency). Space programme demand drove early production. The key breakthrough was cost reduction via silicon wafer manufacturing borrowed from the semiconductor industry. By 2023, global installed capacity exceeded 1,400 GW; levelised cost of solar electricity fell from >USD 80/W (1980) to <USD 0.30/W (2023), a 99.6% reduction — the steepest cost decline of any energy technology.

## Key Actors

- **Companies**: Bell Labs/AT&T (1954), ARCO Solar (1977), First Solar (1999), SunPower (1985), LONGi (2000), BYD, CATL
- **Inventors**: Daryl Chapin (1906–1995), Calvin Fuller (1902–1994), Gerald Pearson (1905–1987)

## Key Patents

- Chapin, D.M., Fuller, C.S. & Pearson, G.L. US Patent 2,780,765 (1957) — silicon solar cell

## Economic Value

Global PV market: **USD 270 billion/year** installed capacity (BloombergNEF 2023). Generating ~3,000 TWh/year of electricity. Expected to grow to USD 1.5T+/year by 2030. Carbon avoidance value at USD 50/tonne CO₂: additional ~USD 150B/year.

## Notes

BloombergNEF *New Energy Outlook* 2023 for cost and capacity data. IRENA *Renewable Power Generation Costs* 2023 for levelised cost trajectory.

## What This Enables

This is a current frontier node — no downstream connections yet recorded in this graph.

## Discovery Character
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**Surprise level**: High — The 99.6% reduction in solar cell cost from 1976 to 2023 — the steepest cost decline of any energy technology in history — was not predicted. In 2010, the IEA forecast solar would provide 3% of global electricity by 2030; it exceeded that level by 2020.
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**Mode**: Systematic-experimental origin; learning-curve-driven cost reduction. Bell Labs' 1954 silicon solar cell was systematic experimental work (Chapin, Fuller, Pearson tested numerous semiconductors before choosing silicon). Subsequent cost reduction was driven by semiconductor manufacturing learning curves — systematic improvement of a known process at scale, with the Swanson's Law cost trajectory resembling Moore's Law.
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# Parents

* [SCI] Semiconductor Physics
* [TECH] Chemical Industry
* [SCI] Semiconductor Physics
* [SCI] Photoelectric Effect