Photoelectrets (Nadjakov effect)
Fotoelectretos (efecto Nadjakov)
- Date
- 1937 · confidence medium
- Place
- Sofia, Bulgaria
- Credited to
- Georgi Nadjakov
- Field
- Cosmos & Earth
What was discovered
The Bulgarian physicist discovered that some insulators, such as sulphur, illuminated in an electric field retain permanent polarisation after the light is switched off. The resulting material was called a photoelectret.
Nadjakov had previously worked in Marie Curie's laboratory in Paris. The electret itself (of wax) had been prepared by Eguchi in Japan in 1925; Nadjakov's novelty was formation by light.
What it led to
- study of photoconductivity in insulators
- the basis of electrophotography
- electrets for microphones and sensors