Aside from being applied on displays, including the renowned QLED TV in recent years, Quantum Dot is also able to elevate solar conversion efficiency. Swiss and South Korean scientists have recently joined hands on developing a Quantum Dot perovskite solar cell that yields a conversion efficiency of 25.7%.
The growth in conversion efficiency has been tremendously remarkable for perovskite cells over the past decade from the initial 3% to more than 24%, and advantages to the particular cell that include low production cost, lightweight, and flexibility have been generating sizable interests for scientists. However, perovskite cells can still be improved in many areas, such as proneness to deterioration and low stability.
Scientists had attempted to elevate the stability in the past by adding macromolecules, additives, and various compounds, and now the École polytechnique fédérale de Lausanne (EPFL) and the Korea Institute of Energy Research have come up with a new method that is adding Quantum Dot to the formula, which managed to create a much more stable solar cell with a high level of efficiency.
Quantum Dot is a type of nanocrystalline semiconductor material, with each dice measuring at approximately 2-10nm in diameter, and its most prominent feature lies on the changeable energy gap according to the sizes of dices, where the larger the dice the smaller the energy gap is. A light of a certain wavelength is emitted when Quantum Dot is under irradiation, making it applicable for various optical applications, including TV and solar energy.
Most Quantum Dots are formed with II-VI, III-V, or IV-VI elements. The research team adopted Quantum Dots that are made with tin oxide as the electron transport layer for perovskite solar. Compared to common electron transport layers of titanium dioxide, Quantum Dots are able to increase the capability of light capture for equipment, as well as reduce adverse reactions in the electron transport layer and electric shock.
Perovskite solar cells are mostly formed with this particular order of components: cathode – electron transport layer – light-absorbing layer of perovskite (active layer) – hole transport layer – anode. The battery would form an electron-hole pair at the active layer when absorbed with sunlight, and scientists would utilize the transport layer to control electrons and holes, which further generates current and voltage.
The research team managed to develop a Quantum Dot perovskite solar cell that yielded an efficiency of 25.7%, and its power generation is considered to be quite remarkable when enlarged to the size of a solar cell, where a Quantum Dot perovskite solar cell at approximately 1cm2 attained a conversion efficiency of 23.3%, with 20cm2 at 21.7%, and 64cm2 at 20.6%, indicating a higher level of conversion efficiency compared to most silicon solar.
(Cover photo source: pixabay)