New photosensitizer proposed – Science Communication Center

They propose a new photosensitizer

Published : 11 November 2022

At the level of quantum-mechanical simulations, researchers propose a mixture of two dyes with optical properties, generating a compound that has properties that make it optimal for use in Grätzel-type solar cells.

Solar energy reaches the Earth in the form of electromagnetic radiation, waves produced by the oscillation or acceleration of an electric charge.

The wavelength (l) and the frequency (m) of electromagnetic waves, related by the expression lm = C (where C is the speed of light), are important to determine their energy, their visibility, their penetrating power and other features.

The Sun emits energy in the form of short-wave radiation, mainly in the ultraviolet, visible, and near-infrared bands.

“One objective of the study is the ability of sensitizers to absorb light in the UV-Vis range and thus improve the design of solar panels,” explains Dr. Ximena Zárate, a researcher at the Institute of Applied Chemical Sciences of the Autonomous University of Chile.

The photosensitizer is one of the most important components of a dye-sensitized solar cell, the so-called Grätzel cells, which is a substance that is activated by the absorption of photons, starting the process of photoconversion of light into electricity.

“Using quantum chemical approaches, through computational simulations, we propose in our work a new photosensitizer, called 1-WS55, which is made up of the union of two dyes, previously evaluated, with excellent optical properties” comments the researcher .

The two dyes used were azulenocyanine, which has a broad absorption in the NIR region of the spectrum (~1000 nm), and WS55, which is a metal-free organic dye that has a photoelectric conversion efficiency of 9.5. %.

As the researcher details, “1-WS55 was found to exhibit panchromatic absorption, that is, along the UV-Vis-NIR region of the electromagnetic spectrum. On the other hand, the study of its electronic and molecular structure shows that the new system can carry out charge transfer processes, which favors the generation of photocurrent».

The next step is, with experimental groups, to test the photoconversion efficiency compared to the molecules that make up the compound.

The published work is part of the FONDECYT Regular 1221072 project: Atomic-Scale modeling of materials and molecular devices base don metal phthalocyanine and organic metal-free dyes for dye-sensitized, in which Dr. Ximena Zárate is a co-investigator with Dr. Gloria Cárdenas-Jirón from the University of Santiago de Chile, and is also part of the ECOS ANID project (ECOS C19E03).

Granados-Tavera, K., Zambrano-Angulo, M., Hidalgo-Rosa, Y., Zarate, X., & Cárdenas-Jirón, G. (2022). Tuning the visible-NIR absorption of azulenocyanine-based photosensitizers. Journal of Molecular Modelling, 28(11), 344.