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Schematic diagram of a thin-film solar cell with a new material as the active layer. Image source: Lehigh University
According to the latest issue of Science Advances, researchers at Lehigh University in the United States have developed a new material that can dramatically improve the efficiency of solar panels. Prototypes using the material as the active layer of solar cells exhibited an average photovoltaic absorption rate of 80%, a high photogenerated carrier generation rate, and an external quantum efficiency (EQE) of up to 190%. This indicator far exceeds the efficiency limit of the Shockley-Kviser theory that breaks through silicon-based materials, and pushes the field of photovoltaic quantum materials to a new level.
According to the researchers, this work represents a major leap forward in understanding and developing sustainable energy solutions. In the future, this innovative approach will redefine the efficiency and accessibility of solar energy.
The increase in the efficiency of this material is largely due to the unique "intermediate energy bands", which are specific energy levels located within the electronic structure of the material. This makes it ideal for solar conversion.
The energy levels of these states are within the optimal sub-band gap (the energy range in which the material can effectively absorb sunlight and generate carriers), which is about 0.78 to 1.26 electron volts. In addition, the material has high absorption levels in the infrared and visible regions of the electromagnetic spectrum.
In conventional solar cells, the maximum EQE is 100%, which represents the generation and collection of one electron for each photon absorbed from sunlight. However, some advanced materials and structures developed in the past few years have demonstrated the ability to generate and collect multiple electrons from high-energy photons, which means that EQEs can exceed 100%. Although such multiple exciton generation materials are not yet widely commercialized, they have the potential to greatly improve the efficiency of solar energy systems.
In the new material, the "intermediate energy band" is able to capture the photon energy lost by conventional solar cells. The researchers developed this new type of 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 are often used by materials scientists to insert or embed other elements in order to adjust material properties.
To develop the new material, the researchers inserted zero-valent copper atoms between layers of a two-dimensional material consisting of germanium selenide and tin sulfide. Subsequently, they developed a prototype that could serve as a proof of concept. It is found that its fast response and improved efficiency strongly demonstrate the potential of copper intercalation as a quantum material in photovoltaic applications, which provides a new way to improve solar energy conversion efficiency.
Source: Science and Technology Daily
Paper link: https://www.science.org/doi/10.1126/sciadv.adl6752
Yangtze River Delta G60 Laser Alliance Chen Changjun reprinted!
At the same time, welcome to the 2nd Conference on the Application of Laser Intelligent Manufacturing in the Energy Storage Industry held by the Yangtze River Delta G60 Laser Alliance in Nanjing (Nanjing, April 23-25, 2024)