An international group of scientists led by specialists from the National Research Nuclear University “MEPhI” (NRNU MEPhI) believes that their work will help to increase the quality of operation of solar cells, organic light-emitting diodes and other photovoltaic equipment by several times.
An exciton is a quasiparticle, an auxiliary object of quantum theory, the behavior of which describes the bound state of a pair of carriers of opposite charges. This concept, the authors of the work note, makes it possible to very accurately describe, for example, the electrical properties of organic semiconductors when interacting with light.
When an exciton is born or destroyed, a resonant energy transformation occurs in the organic semiconductor. Along with this event, a photon is absorbed or emitted. In a new article, the research team showed the possibility of controlling the properties of exciton transitions using the strong coupling effect.
The strong coupling effect consists in the formation of a hybrid energy state between excitation in matter, which is described using the concept of an exciton, and localized electromagnetic excitation. To create such conditions, special resonators are used, which are based on a pair of mirrors located opposite each other at a distance of the order of the wavelength of light.
Igor Nabiev, Leading Scientist of the Laboratory of Nano-Bioengineering (LNBE), National Research Nuclear University MEPhI
The term exiton is used for one of the effects in organic semiconductors – the Förster resonant energy transfer (FRET). It is used in medical technology. The bottom line is that there is a lossless transfer of energy between two exciton states in different molecules located at a small distance from each other.
To make wider use of the potential of this phenomenon in photovoltaics, it was necessary to experimentally record and study the so-called carnival effect, which consists in a controlled change in the directions of energy transfer in the FRET mode between excitons of different molecules.
The authors believe that their work can be applied to photovoltaic devices that convert light energy into electrical energy. For example, the efficiency of solar panels can increase several times. They also want to use it for precise remote control of chemical reactions.