# Richard Henry Friend
**Sir Richard Henry Friend** is a physicist who pioneered the understanding and use of semiconductors made from organic, carbon-based materials, work that produced the first polymer light-emitting diodes and founded the field of plastic electronics.[1](https://royalsociety.org/people/richard-friend-11470/) According to [St John's College, Cambridge](https://www.edgepedia.org/st-johns-college-cambridge), he held the Cavendish Professorship of Physics at the [University of Cambridge](https://www.edgepedia.org/university-of-cambridge) from 1995 to 2020 and became a Director of Research in the [Cavendish Laboratory](https://www.edgepedia.org/cavendish-laboratory) and Tan Chin Tuan Centennial Professor at the National University of Singapore.[2](https://www.joh.cam.ac.uk/research/academics/fellows/professor-sir-richard-friend) • [3](https://www.royce.ac.uk/our-people/professor-sir-richard-friend-2/) His honors include election as Fellow of the Royal Society in 1993, a knighthood in 2003 for services to physics, the 2010 Millennium Technology Prize, and the 2024 Isaac Newton Medal of the Institute of Physics.[1](https://royalsociety.org/people/richard-friend-11470/) • [4](https://finlandabroad.fi/documents/384951/405231/richard_friend.pdf/1a270347-5862-07c6-81e6-74402ba94d0e?t=1548856407749) • [5](https://www.iop.org/about/awards/2024-isaac-newton-medal-and-prize)
| Key fact | Detail |
|---|---|
| Born | 1953, London, UK; British |
| Signature work | First polymer LEDs (1990); "Spin-dependent exciton formation in π-conjugated compounds" (Nature, 2001)[6](https://doi.org/10.1038/35101565); ["Electroluminescence in conjugated polymers"](https://doi.org/10.1038/16393), *Nature*, 1999 |
| Principal chair | Cavendish Professor of Physics, Cambridge, 1995–2020; Director of Research since then; Tan Chin Tuan Centennial Professor, NUS[2](https://www.joh.cam.ac.uk/research/academics/fellows/professor-sir-richard-friend) • [3](https://www.royce.ac.uk/our-people/professor-sir-richard-friend-2/) |
| Companies co-founded | Cambridge Display Technology (1992), Plastic Logic (2000), Eight-19 Ltd[7](https://www.cam.ac.uk/research/news/plastic-logic-from-innovation-to-impact) • [8](https://www.energy.cam.ac.uk/people/professor-sir-richard-friend-frs-freng) |
| Major honors | FRS 1993; knighthood 2003; Millennium Technology Prize 2010; Isaac Newton Medal 2024[1](https://royalsociety.org/people/richard-friend-11470/) • [4](https://finlandabroad.fi/documents/384951/405231/richard_friend.pdf/1a270347-5862-07c6-81e6-74402ba94d0e?t=1548856407749) • [5](https://www.iop.org/about/awards/2024-isaac-newton-medal-and-prize) |
## Education and early career
Friend read Theoretical Physics at [Trinity College, Cambridge](https://www.edgepedia.org/trinity-college-cambridge). According to [Who's Who](https://www.edgepedia.org/whos-who), he has been a Fellow of St John's College since 1977, with a Teaching Fellowship there from 1980 to 1995.[2](https://www.joh.cam.ac.uk/research/academics/fellows/professor-sir-richard-friend) • [4](https://finlandabroad.fi/documents/384951/405231/richard_friend.pdf/1a270347-5862-07c6-81e6-74402ba94d0e?t=1548856407749)
## Polymer LEDs and the birth of plastic electronics
The discovery came in 1989, when a doctoral student in Friend's laboratory applied a voltage to a device containing the conjugated polymer PPV with a semi-transparent aluminum top electrode and saw green light shining through the metal film.[7](https://www.cam.ac.uk/research/news/plastic-logic-from-innovation-to-impact) Patents were filed in April 1989 and April 1990, and in October 1990 the team published a letter in Nature titled "Light-emitting diodes based on conjugated polymers".[7](https://www.cam.ac.uk/research/news/plastic-logic-from-innovation-to-impact) The result was a breakthrough because the materials were structurally disordered yet still gave clean diode behavior, and it showed polymers could be used as solution-processed semiconductors, deposited by printing rather than high-temperature crystal growth.[5](https://www.iop.org/about/awards/2024-isaac-newton-medal-and-prize) • [4](https://finlandabroad.fi/documents/384951/405231/richard_friend.pdf/1a270347-5862-07c6-81e6-74402ba94d0e?t=1548856407749) The Institute of Physics records that the 1990 discovery triggered substantial academic and industrial research activity.[5](https://www.iop.org/about/awards/2024-isaac-newton-medal-and-prize)
The underlying physics is exciton-based. When an electron and hole meet in an organic semiconductor they form a bound pair whose two spins can be arranged as zero-spin singlet states, which emit light, or spin-1 triplet states, which in solar cells separate to give free charge.[9](https://royalsocietypublishing.org/doi/10.1098/rsta.2015.0121)
## Representative work
- **Spin-dependent exciton formation in π-conjugated compounds** (Nature, 1 October 2001): the experimental demonstration that the fraction of emissive singlet excitons formed in organic LEDs is far above the value spin statistics predict. [https://doi.org/10.1038/35101565](https://doi.org/10.1038/35101565)[6](https://doi.org/10.1038/35101565)
- **Conjugated polymers. New materials for optoelectronic devices** (Pure and Applied Chemistry, 2001): the review reporting polymer LEDs across red, green, and blue with efficiencies above 20 lumen/W for green emitters, and their integration with active-matrix TFT displays and inkjet printing. [https://doi.org/10.1351/pac200173030425](https://doi.org/10.1351/pac200173030425)[10](https://doi.org/10.1351/pac200173030425)
The spin work changed device efficiency limits. Spin statistics had been assumed to cap organic LED efficiency at 25%, since exchange energies above 0.5 eV should favor triplet formation; experiments showed the singlet fraction can be considerably higher, of order 45%.[10](https://doi.org/10.1351/pac200173030425)
## Industry roles and commercialization
According to the University of Cambridge, after failing to find a UK electronics company to license the invention, Friend founded Cambridge Display Technology in 1992 with help from the University and local seed venture capital; the company floated on NASDAQ in 2004 and was acquired by [Sumitomo Chemical](https://www.edgepedia.org/sumitomo-chemical) in 2007, where the polymer LED technology is described as fully commercialized.[7](https://www.cam.ac.uk/research/news/plastic-logic-from-innovation-to-impact) Plastic Logic was formed in January 2000 to develop printed transistor circuits; by 2006, according to the University of Cambridge, it had built a display with a million transistors and raised more than US$100 million for a manufacturing plant in Dresden.[7](https://www.cam.ac.uk/research/news/plastic-logic-from-innovation-to-impact) He later co-founded Eight-19 Ltd to develop organic solar cell manufacturing and became a non-executive director of Eight-19 and of Azuri Technologies, which markets pay-as-you-go solar lighting.[8](https://www.energy.cam.ac.uk/people/professor-sir-richard-friend-frs-freng) Organic semiconductors now support an industry worth over $60 billion (about £45 billion).[12](https://www.cam.ac.uk/research/news/spinning-twisted-light-could-power-next-generation-electronics)
## Honours and awards
Friend was elected a [Fellow of the Royal Society](https://www.edgepedia.org/fellow-of-the-royal-society) in 1993 and, according to the [Institute of Physics](https://www.edgepedia.org/institute-of-physics), was knighted in the 2003 Queen's Birthday Honours for services to physics.[1](https://royalsociety.org/people/richard-friend-11470/) • [11](https://www.iop.org/about/awards/honorary-fellowship/our-honorary-fellows/sir-richard-henry-friend) He was elected an Honorary Fellow of the Institute of Physics in 2008 for his research and its exploitation through Cambridge Display Technology and Plastic Logic.[11](https://www.iop.org/about/awards/honorary-fellowship/our-honorary-fellows/sir-richard-henry-friend) The 2010 [Millennium Technology Prize](https://www.edgepedia.org/millennium-technology-prize) recognized his contributions to plastic electronics, citing organic LEDs as a crucial milestone and naming electronic paper, cheap organic solar cells, and illuminating wallpaper as products the work made possible.[4](https://finlandabroad.fi/documents/384951/405231/richard_friend.pdf/1a270347-5862-07c6-81e6-74402ba94d0e?t=1548856407749) In 2024 he received the Isaac Newton Medal and Lecture for pioneering and enduring work on the fundamental electronic properties of molecular semiconductors and their engineering development.[5](https://www.iop.org/about/awards/2024-isaac-newton-medal-and-prize)
## Recent developments
His current group works on three fronts. For LEDs, it explores molecular structures with low exchange energy and, in the ERC-funded SCORS project, spin-radical materials whose unpaired electrons allow efficient light emission entirely within the spin doublet manifold.[13](https://www.phy.cam.ac.uk/profile/prof-sir-richard-friend-frs-freng/) • [5](https://www.iop.org/about/awards/2024-isaac-newton-medal-and-prize) For solar energy, the spin-radical semiconductor P3TTM was reported in [Nature Materials](https://www.edgepedia.org/nature-materials) in October 2025 to show Mott-Hubbard-like intrinsic photoinduced charge separation, and a device made from a single P3TTM film achieved close-to-unity charge collection, meaning almost every absorbed photon became usable charge.[14](https://www.phy.cam.ac.uk/news/new-organic-molecule-set-to-transform-solar-energy-harvesting/) A 2025 Science paper reported a helical triazatruxene-based chiral semiconductor incorporated into circularly polarized OLEDs with record efficiency, brightness, and polarization levels.[12](https://www.cam.ac.uk/research/news/spinning-twisted-light-could-power-next-generation-electronics) [Perovskite](https://www.edgepedia.org/perovskite) research continues into quantum well structures built from two-dimensional metal halide perovskites with controlled bandgaps.[13](https://www.phy.cam.ac.uk/profile/prof-sir-richard-friend-frs-freng/)
## References
1. Sir Richard Friend FREng FRS, Royal Society, https://royalsociety.org/people/richard-friend-11470/
2. Professor Sir Richard Friend, St John's College, Cambridge, https://www.joh.cam.ac.uk/research/academics/fellows/professor-sir-richard-friend
3. Professor Sir Richard Friend, Henry Royce Institute, https://www.royce.ac.uk/our-people/professor-sir-richard-friend-2/
4. The Millennium Technology Prize Laureate 2010, Richard Friend, https://finlandabroad.fi/documents/384951/405231/richard_friend.pdf/1a270347-5862-07c6-81e6-74402ba94d0e?t=1548856407749
5. 2024 Isaac Newton Medal and Lecture, Institute of Physics, https://www.iop.org/about/awards/2024-isaac-newton-medal-and-prize
6. Spin-dependent exciton formation in π-conjugated compounds, Nature (2001), https://doi.org/10.1038/35101565
7. Plastic Logic: from innovation to impact, University of Cambridge, https://www.cam.ac.uk/research/news/plastic-logic-from-innovation-to-impact
8. Professor Sir Richard Friend, Cambridge Energy IRC, https://www.energy.cam.ac.uk/people/professor-sir-richard-friend-frs-freng
9. Organic semiconductor spintronics, Phil. Trans. R. Soc. A, https://royalsocietypublishing.org/doi/10.1098/rsta.2015.0121
10. Conjugated polymers. New materials for optoelectronic devices, Pure and Applied Chemistry (2001), https://doi.org/10.1351/pac200173030425
11. Honorary Fellows: Sir Richard Henry Friend, Institute of Physics, https://www.iop.org/about/awards/honorary-fellowship/our-honorary-fellows/sir-richard-henry-friend
12. Spinning, twisted light could power next-generation electronics, University of Cambridge, https://www.cam.ac.uk/research/news/spinning-twisted-light-could-power-next-generation-electronics
13. Prof. Sir Richard Friend, Cavendish Laboratory profile, https://www.phy.cam.ac.uk/profile/prof-sir-richard-friend-frs-freng/
14. New organic molecule set to transform solar energy harvesting, Cavendish Laboratory, https://www.phy.cam.ac.uk/news/new-organic-molecule-set-to-transform-solar-energy-harvesting/
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*Topic: Encyclopedia › Technology and the built world › Engineers and computer scientists › Engineers and materials scientists › Researchers in materials science and nanotechnology › Electronic and photonic materials (semiconductors, optoelectronics)*
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