Quantum dots boost perovskite solar cell effectiveness and scalability

• Perovskites are hybrid substances made from steel halides and organic components. They show excellent potential in a series of applications, e.g. LED lights, lasers, as well as photodetectors, yet their major payment remains in solar cells, where they are poised to surpass the market from their silicon equivalents.

Among the challenges encountering the commercialization of perovskite solar cells is that their power-conversion performance as well as functional stability decline as they scale up, making it a challenge to maintain high performance in a total solar cell.

The trouble is partly with the cell's electron-transport layer, which makes certain that the electrons created when the cell soaks up light will certainly transfer successfully to the device's electrode. In perovskite solar cells, the electron-transport layer is made with mesoporous titanium dioxide, which reveals low electron wheelchair, as well as is likewise prone to adverse, photocatalytic events under ultraviolet light.

In a new publication in Science, scientists led by Professor Michael Grätzel at EPFL and Dr. Dong Suk Kim at the Korea Institute of Energy Research have located an innovative method to enhance the efficiency as well as keep it at a high level in perovskite solar cells also at large scales. The cutting-edge concept was to replace the electron-transport layer with a thin layer of quantum dots.

Quantum dots are nanometer-sized bits that serve as semiconductors, and also emit light of details wavelengths (colors) when they are brightened. Their unique optical homes make quantum dots optimal for use in a variety of optical applications, consisting of photovoltaic devices.

The researchers replaced the titanium dioxide electron-transport layer of their perovskite cells with a thin layer of polyacrylic acid-- maintained tin(IV) oxide quantum dots, as well as discovered that it boosted the devices' light-capturing capacity, while likewise subduing nonradiative recombination, an efficiency-sapping sensation that often tackles the user interface between the electron-transport layer and also the real perovskite layer.

By using the quantum dot layer, the scientists discovered that perovskite solar cells of 0.08 square centimeters achieved a record power-conversion performance of 25.7% (qualified 25.4%) and also high operational stability, while helping with the scale-up. When boosting the surface of the solar cells to 1, 20, and also 64 square centimeters, power-conversion efficiency determined at 23.3, 21.7, and 20.6% specifically.