Nanowires promise to make LEDs more colorful and solar cells more efficient, in addition to speeding up computers. That is, provided that the tiny semiconductors convert electric energy into light, and vice versa, at the right wavelengths. A research team at the German Helmholtz-Zentrum Dresden-Rossendorf (HZDR) has managed to produce nanowires with operating wavelengths that can be freely selected over a wide range—simply by altering the shell structure. Fine-tuned nanowires could take on several roles in an optoelectronic component. That would make the components more powerful, more cost-effective, and easier to integrate, as the team reports in Nature Communications.