[19:18 Mon,7.July 2025 by blip] |
So far, silicon has always been used in image sensors to convert the incident light into electrical charges, which in turn are the basis of digital images. However, there seems to be a fundamentally more effective semiconductor material for this task: It is called perovskite and is used in some cases in photovoltaics. Researchers at ETH Zurich have been working for several years on a new type of image sensor which, thanks to perovskite, should be both more light-sensitive and higher-resolution than image converters available to date. ;) Perovskite sensor as thin-film prototype
More precisely, a three times higher light yield as well as resolution should be achievable on a comparable area, because the special thing about perovskite is its light transmission. While sensor pixels on silicon sensors obtain their red, green or blue sensitivity via filter methods and can therefore only be arranged next to each other, it is possible to place three sensor layers made of perovskite on top of each other, with each layer responding to one of the required wavelengths. This is because the physical properties of the semiconductor vary with its exact chemical composition: If the perovskite contains a little more iodine ions, it absorbs red light. For green, the researchers add more bromine, for blue more chlorine - without any filters. For the other wavelengths, the perovskite pixel layers remain transparent, i.e. let them through. ;){kind=tracking} According to the researchers, such perovskite sensors should also be able to reproduce colors more precisely, and since each pixel captures all the light, some artifacts of digital photography, such as demosaicing and the moiré effect, are also eliminated. However, it will take even longer before this new type of sensor can be used: As a proof of concept, two functioning thin-film image sensors made of perovskite have now been built for the first time. In a next step, the researchers want to further reduce the size of their perovskite image sensors and at the same time increase the number of pixels. The two prototypes have pixel sizes between 0.5 and 1 millimeter, while pixels in commercial image sensors are in the micrometer range. The electronic connections and processing techniques for the new technology also need to be adapted, as today&s readout electronics are optimized for silicon. The new technology should also bring advantages for machine vision, as the individual perovskite layers can also be tuned for completely different wavelengths - the R-G-B structure is ultimately designed for human eyes. Hyperspectral image sensors made of perovskite could be used, for example, in the field of medical analysis or in the automated monitoring of agriculture and the environment. (Thanks to CotORR for the hint in the forum; here is the current study in  Nature.)  more infos at bei ethz.chdeutsche Version dieser Seite: Neue, mehrschichtige Bildsensoren könnten 3-fache Lichtausbeute und Auflösung ermöglichen |
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