Weidong Xu (IMAGE) Linköping University Caption Weidong Xu, postdoc at the Department of Physics, Chemistry and Biology at Linköping University, Sweden is part of the research group that have developed efficient blue light-emitting diodes based on halide perovskites Credit Thor Balkhed Usage Restrictions Please use appropriate caption and credit. License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.