Great efficiency beneficial properties in perovskite–silicon tandem solar cells (a lot like that pictured right here) can even be achieved by including a magnesium fluoride interlayer. Credit: © 2022 KAUST; Erkan Aydin
An additional metal fluoride layer enables charge separation and boosts efficiency in perovskite–silicon tandem solar cells.
Inserting a metal fluoride layer in multilayered perovskite–silicon tandem solar cells can stall charge recombination and increase efficiency, King Abdullah University of Science & Expertise (KAUST) researchers salvage chanced on.
Tandem solar cells that combine perovskite and silicon-primarily based mostly subcells in one tool are anticipated to greater capture and convert daylight hours into electrical energy than their archaic single-junction silicon competitors. And they also are anticipated to procedure so at a decrease cost. However, when daylight hours strikes the perovskite subcell, the following pairs of electrons and positively charged holes are inclined to recombine at the interface between perovskite and the electron-transport layer. Furthermore, a mismatch between vitality phases at this interface hinders electron separation at some stage in the cell. These points together decrease the tandem cells’ commence-circuit voltage, or most working voltage, which restricts tool efficiency.
By including a layer of lithium fluoride between the perovskite and the electron-transport layer, which on the total contains the electron-acceptor fullerene (C60), these efficiency concerns would possibly presumably well be partly resolved. However, the devices turn into unstable because lithium salts without issues liquefy and diffuse thru surfaces. Lead creator Jiang Liu, a postdoc in Stefaan De Wolf’s community, states, “None of the devices salvage handed the routine check protocols of the World Electrotechnical Commission, prompting us to rep an different.”
Liu, De Wolf, and colleagues systematically investigated the capacity of assorted metal fluorides, a lot like magnesium fluoride, as interlayer offers at the perovskite/C60 interface of tandem cells. They thermally evaporated the metal fluorides on the perovskite layer to procedure an ultrathin uniform movie with controlled thickness earlier than including C60 and high contact parts. The interlayers are also extremely clear and proper, per the inverted p-i-n solar cell necessities.
The magnesium fluoride interlayer successfully promoted electron extraction from the perovskite active layer while displacing C60 from the perovskite ground. This reduced charge recombination at the interface. It also enhanced charge transport across the subcell.
The ensuing tandem solar cell achieved a 50 millivolt amplify in its commence-contemporary voltage and a licensed stabilized vitality conversion efficiency of 29.3 p.c — one of the most effective efficiencies for perovskite–silicon tandem cells, Liu says.
“All in favour of that primarily the most uncomplicated efficiency is 26.7 p.c for mainstream crystalline silicon-primarily based mostly single-junction cells, this modern abilities would possibly presumably well bring well-known efficiency beneficial properties without including to the cost of fabrication,” Liu says.
To extra explore the applicability of this abilities, the study group is constructing scalable techniques to rep industrial-scale perovskite–silicon tandem cells with areas exceeding 200 sq. centimeters (31 sq. inches). “We’re also constructing several techniques to execute extremely proper tandem devices that can cross the serious industrial steadiness protocols,” Liu says.
Reference: “Atmosphere pleasant and proper perovskite-silicon tandem solar cells thru contact displacement by MgFx” by Jiang Liu, Michele De Bastiani, Erkan Aydin, George T. Harrison, Yajun Gao, Rakesh R. Pradhan, Mathan Good sufficient. Eswaran, Mukunda Mandal, Wenbo Yan, Akmaral Seitkhan, Maxime Babics, Anand S. Subbiah, Esma Ugur, Fuzong Xu, Lujia Xu, Mingcong Wang, Atteq ur Rehman, Arsalan Razzaq, Jingxuan Kang, Randi Azmi, Ahmed Ali Said, Furkan H. Isikgor, Thomas G. Allen, Denis Andrienko, Udo Schwingenschlögl, Frédéric Laquai, Stefaan De Wolf, 23 June 2022, Science.
DOI: 10.1126/science.abn8910