Researchers at the Department of Energy's Lawrence Berkeley National Laboratory (Berkeley Lab) have demonstrated that halide perovskites are capable of discharging multiple, bright colors from just one nanowire at resolutions as small as 500 nm. This work could impact the development of new applications in optoelectronics, nanoscopic lasers, photovoltaics and more.
The team used electron beam lithography to fabricate halide perovskite nanowire heterojunctions, the junction of two types of semiconductors. The researchers analyzed cesium lead halide perovskite, and then used a common nanofabrication method integrated with anion exchange chemistry to switch out the halide ions to form cesium lead bromide, cesium lead iodide and cesium lead chloride perovskites. Each difference resulted in a different color discharged.
Furthermore, the Researchers demonstrated that a number of heterojunctions could be engineered on a single nanowire. They were able to achieve a pixel size down to 500 nm, and established that the color of the material was tunable all the way through the entire range of visible light.
The Researchers said that the chemical solution-processing method used to treat this class of soft, ionic-bonded semiconductors is a lot simpler than approaches used to make traditional colloidal semiconductors. To switch the anions in a soft semiconductor, the material is put into a special chemical solution at room temperature.
The Researchers are continuing to enhance the resolution of these soft semiconductors and aim to incorporate them into an electric circuit.
