# [TECH] Solar Cells (Photovoltaics)
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**Solar Cells** convert sunlight directly into electricity via the photovoltaic effect, and have become the cheapest source of electricity in history as of 2020.
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## Overview
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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 >$80/W (1980) to <$0.30/W (2023), a 99.6% reduction — the steepest cost decline of any energy technology.
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## Key Actors
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- **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)
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## Key Patents
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- Chapin, D.M., Fuller, C.S. & Pearson, G.L. US Patent 2,780,765 (1957) — silicon solar cell
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## Economic Value
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Global PV market: **$270 billion/year** installed capacity (BloombergNEF 2023). Generating ~3,000 TWh/year of electricity. Expected to grow to $1.5T+/year by 2030. Carbon avoidance value at $50/tonne CO₂: additional ~$150B/year.
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## Notes
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BloombergNEF *New Energy Outlook* 2023 for cost and capacity data. IRENA *Renewable Power Generation Costs* 2023 for levelised cost trajectory.
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# Parents
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* [SCI] Semiconductor Physics⏎