Image: Researchers use potassium to 'cure' perovskite solar cells. Photo: Provided by Cambridge University.
An international team of scientists at Cambridge University found that the addition of potassium iodide 'cure' the defect and immobilize the ion movement. These factors have become the limiting factor for the efficiency of low-cost perovskite solar cells.
The next generation of solar cells can be used as the energy efficiency enhancement layer on top of existing silicon-based solar cells.
The solar cells under study are based on metal halide perovskites, which are cheap and easy to produce at low temperatures. These properties make perovskites attractive for the next generation of solar cells and lighting.
However, even with these advantages, there are limitations that hamper their efficiency and consistency. The tiny defects in the crystal structure of the perovskite, known as traps, may cause the electrons to 'stuck' before releasing energy.
Dr. Sam Stranks, who is in charge of research at the Cavendish Laboratory in Cambridge, said: “So far, we have not been able to stabilize these materials with the band gap we need, so we’ve been trying to fix the ion motion by adjusting the chemical composition. Perovskite layer. '
'This will enable perovskites to be used to make multi-functional solar cells or colored LEDs, which are essentially the reverse operation of solar cells.'
In this study, the scientists changed the chemical composition of the perovskite layer by adding potassium iodide to the perovskite ink.
Potassium iodide forms a layer on the top of the perovskite, which has the function of 'healing' traps, allowing electrons to move more freely and moving the fixed ions.
Stranks said: 'Potassium can stabilize the perovskite band gaps of the solar cells we want to connect in series and make them easier to emit, which means that more efficient solar cells can be made.'
'It almost completely controls the ions and defects in the perovskite.'
