Researchers at Lehigh University have created a revolutionary solar cell material with an external quantum efficiency of up to 190%, surpassing the traditional efficiency limit, showing great promise for enhancing future solar systems. With funding from the U.S. Department of Energy, practical applications require further development. It shows great potential to drive the development of high-efficiency next-generation solar cells, which are critical to meeting global energy demand.
A research team at Lehigh University in the United States has created a material that can greatly improve the efficiency of solar panels.
Prototypes using this material as the active layer of solar cells show an average photoabsorption rate of 80%, a high photoexcited carrier generation rate, and an unprecedented external quantum efficiency (EQE) of up to 190% – which far exceeds the Shockley-Quessel theoretical efficiency limit for silicon-based materials and pushes the field of photovoltaic quantum materials to new heights.
Chindeau Ekuma. 资料来源:利哈伊大学
Physics professor Chinedu Ekuma published his paper in the journal Science Advances in which he collaborated with Srihari Kastuar, a PhD student at Lehigh University, to develop the material.
Advanced material properties
This material's efficiency leap is largely due to its unique "intermediate band state", a specific energy level in the material's electronic structure, making it ideal for solar energy conversion.
The energy levels of these states are within the optimal subband gap, i.e., the energy range in which the material can effectively absorb sunlight and produce charge carriers, which is about 0.78 and 1.26 electron volts.
In addition, the material excels at its high absorption rates in the infrared and visible regions of the electromagnetic spectrum.
Schematic diagram of a thin-film solar cell with CuxGeSe/SnS as the active layer. Source: Ekuma Lab/Lehigh University
In conventional solar cells, the maximum EQE is 100%, i.e., for every photon absorbed from sunlight, an electron is produced and collected. However, some advanced materials and configurations developed in the last few years have demonstrated the ability to generate and collect more than one electron from high-energy photons, i.e., EQE exceeds 100%.
Sri Hari Kastuar, Lehigh University. Source: Lehigh University
While such multiple exciton generation (MEG) materials are not yet widely commercialized, they have the potential to significantly improve the efficiency of solar power systems. In the materials developed by Lehigh, the intermediate band state is able to capture the photon energy lost by conventional solar cells through reflection and heat production, among other things.
Material development and potential
The researchers developed the new material using "van der Waals gaps", which are small atomic-scale gaps between layered two-dimensional materials. These gaps can confine molecules or ions, and materials scientists often use them to insert or "interpolate" other elements in order to adjust material properties.
To develop the new material, researchers at Lehigh University inserted zero-valent copper atoms between layers of two-dimensional materials made of germanium selenide (GeSe) and tin sulfide (SnS).
Ekuma is an expert in computational condensed matter physics, and after extensive computer modeling of the system and proving its theoretical prospects, he developed this prototype as a proof of concept.
"Its fast response and higher efficiency strongly demonstrate the potential of copper-doped GeSe/SnS as a quantum material in advanced photovoltaic applications, providing a way to improve solar energy conversion efficiency," he said. This is an ideal candidate for the development of a new generation of high-efficiency solar cells that will play a vital role in meeting global energy demand. "
While further research and development is needed to integrate newly designed quantum materials into current solar systems, Ekuma noted that the experimental techniques used to fabricate these materials are already very advanced. Over time, scientists have mastered the method of inserting atoms, ions, and molecules into materials with precision.
编译自:ScitechDaily