Scientists have developed a method of bettering the packing of two newly designed photosensitizer dye molecules to reinforce the mesoscopic dye-sensitized photo voltaic cell’s photovoltaic efficiency.
In the 1990s, mesoscopic dye-sensitized photo voltaic cells (DSCs) had been invented by Brian O’Regan and Michael Grätzel, taking over the latter’s identify – the world-famous Grätzel cells. DSCs convert mild into electrical energy by photosensitizers. These are dye compounds that take up mild and inject electrons into an array of oxide nanocrystals that are subsequently collected as electrical present.
In DSCs, photosensitizers are hooked up (“adsorbed”) to the floor of nanocrystalline mesoporous titanium dioxide movies which might be imbibed with redox-active electrolytes or a stable charge-transport materials. The whole design goals to generate electrical energy by transferring electrons from the photosensitizer towards {an electrical} output like a tool or a storage unit.
DSCs are clear, might be fabricated in a number of colours for low price, and are already being utilized in skylights, greenhouses, in addition to glass facades, similar to these adorning the SwissTech Convention Center. In addition, light-weight versatile variations of DSCs at the moment are commercially offered on a big scale for utilizing ambient mild to generate electrical energy for transportable digital gadgets similar to earphones and e-readers, in addition to within the Internet of Things.
Recent developments in photosensitizers and different parts of DSCs have improved the efficiency of DSCs below each photo voltaic daylight and ambient mild situations. But the important thing to enhancing DSC effectivity lies in understanding and controlling the meeting of dye molecules on the floor of titanium dioxide nanoparticle movies that favor the technology {of electrical} cost.
One methodology is cosensitization, a chemical fabrication method that produces DSCs with two or extra completely different dyes which have complementary optical absorption. Cosensitization has moved the power-conversion efficiencies of DSCs in direction of world-record values as a result of it may conceivably mix dyes that may take up mild from throughout your complete mild spectrum. Nonetheless, cosensitization has additionally proved ineffective in some instances since discovering the suitable pairs of dyes that may obtain excessive mild absorption and energy conversion effectivity requires painstaking molecular design, synthesis, and screening.
Now, scientists from the teams of Grätzel and Anders Hagfeldt at EPFL have developed a method of bettering the packing of two newly designed photosensitizer dye molecules to reinforce the DSC’s photovoltaic efficiency. Together, the brand new photosensitizers can harvest mild quantitatively throughout your complete seen area. The new method entails pre-adsorbing a monolayer of a spinoff of hydroxamic acid on the surface of nanocrystalline mesoporous titanium dioxide. This slows down the adsorption of the two sensitizers, enabling the formation of a well-ordered and densely packed layer of sensitizer at the titanium dioxide surface.
With this approach, the team was able to develop DSCs with a power conversion efficiency of 15.2% for the first time under standard global simulated sunlight, with long-term operational stability tested over 500 hours. By increasing the active area to 2.8 cm2, the power conversion efficiency spanned 28.4% – 30.2% over a wide range of ambient light intensities along with outstanding stability.
The authors write: “Our findings pave the way for facile access to high-performance DSCs and offer promising prospects for applications as power supply and battery replacement for low-power electronic devices that use ambient light as their energy source.”
Reference: “Hydroxamic acid preadsorption raises efficiency of cosensitized solar cells” by Yameng Ren, Dan Zhang, Jiajia Suo, Yiming Cao, Felix T. Eickemeyer, Nick Vlachopoulos, Shaik M. Zakeeruddin, Anders Hagfeldt and Michael Grätzel, 26 October 2022, Nature.
DOI: 10.1038/s41586-022-05460-z
