Accident opens the way for innovation

Scientific incidents sometimes bring completely unexpected results. So, largely due to chance, vulcanized rubber, X-rays, penicillin, local anesthesia, and more appeared. And nowadays, researchers from the UCLA Science Center , which is located in glorious Los Angeles, have unexpectedly stumbled upon the material, thanks to which digital cameras in the form in which we got used to them, may soon become just a piece of history.

Graduate student Sang-Yu Chen (Hsiang-Yu Chen) was working on a new formula for solar cells when something went wrong. Instead of generating electricity, in contact with direct sunlight, the conductivity of the material with which it worked changed.

“The original goal was to create a more efficient solar panel,” says Chen. “Anyway, during the course of the study, we saw that the properties of the solar panel simply disappeared.” Instead of generating electricity, the test material became highly photosensitive, prompting the idea of ​​using it as a sensor.
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Thanks to lucky chance, it is possible that soon a new type of digital photo and video cameras will appear on the horizon, inside of which there will be cheaper and high-quality matrices, besides, having lower noise levels than today's ones. Under the cut there will be photos with descriptions.
The photo above shows five strips of new material on a glass substrate, which Chen holds with forceps in a sterile box.


In this photo, Sang-Yu Chen takes a polymer sample from a test tube. Researchers in this laboratory are testing hundreds of materials before there is at least one whose properties are suitable for further experiments.

When Chen made her discovery, she worked with a substance resembling plastic coated with quantum dots — nanoparticles (about the size of a virus), whose properties are similar to those of semiconductors. Quantum nanoparticles, if successful, would provide a new type of matrix, an unprecedented, even by today's standards, resolution. And since this new material is a plastic tape, it is flexible and could one day be very cheap.


At the top you can see a pair of containers containing concentrates of various polymers. Later they will all be tested for reaction to sunlight.

Today’s matrices in digital cameras, the ones that determine the presence of light and allow you to take a picture, are made of silicon. This makes them quite expensive and, at the same time, flat and solid. It would seem that everything is in order, even if the sensor is flat, but it only seems that way until we think about how the lenses of the lenses work. Indeed, depending on the curvature of the glass, the image that is produced at the output also changes. And when a spherical image is projected on a flat surface, it turns out that near the corners the noise level is quite high. A flexible matrix would prevent such a phenomenon.


Now the polymer deposited on the substrate is enclosed in a metal sheath and placed in an electrode clip (white thing, part of the installation). Its task is that the sensor “read” the information when it is brought to light. This is how all light-sensitive materials work, but here the process of obtaining information about how well the polymer perceives the “picture” is a serious task.


Now a test copy of the polymer inside the clip is placed in the test setup. Wires, well distinguishable from the right side, will send any electrical activity of the material to the computer for further analysis.



Surely you noticed that all these operations were carried out in an isolated sterile box. Now a very bright broad-spectrum light source was connected to it. Moreover, the distance from the source to the test material is rigidly fixed. Despite the fact that the light appears blue in the photograph (this is due to the fact that the laboratory has a yellow light), in fact it is as close as possible to the color of daylight.



Chen checks the test results using a computer and special software designed for the laboratory. The graphs, in the form of which the processed information is displayed, correspond to the level of reaction of the material to light.

In the original experiment, the young talent was hoping to see as a result electricity, which would inevitably be produced when the light came in contact with the polymer, but instead light stopped the flow of electricity. This phenomenon suggests that the material being tested behaves like a photosensitive matrix, and not a solar battery.

Despite the fact that the main focus of the laboratory is still the issue of solar cell efficiency, the results obtained by Chen have already been published. Now the question of technology has become only a matter of time, since many companies producing photo and video equipment have already paid attention to this find.


A scanning atomic force microscope ( AFM ) is used to obtain an image of the polymer profile and look at its atomic structure. A nano-needle passes along the surface in almost the same way as a needle of a turntable.

This needle is attached to the cantilever, which reflects the laser beam, because of which the output is a three-dimensional topographic image of the surface. It allows researchers to make sure that quantum dots are correctly located over the entire area of ​​the polymer.


But a scanning tunneling microscope ( STM ) is used to determine the physical structure of the polymer. The level of detail of the image obtained using the STM is equal to several hundreds of nanometers. The photo above shows a micro-image of a photosensitive (now without a doubt) polymer.

Chen's letter, sent to Nature with a message about a random, but not non-stop, innovative find, is here . It remains to wish good luck to the young girl, whose interest in their work may well bring all of humanity to a qualitatively new level of understanding of what “video” and “photo” are.

Thank you guys from Wired