�ʹ�����

by Dongze Wang and Prof. Jun Gao has been published in the prestigious Physical Review Letters as Editor's Suggestion. The interesting findings have also been featured in in the Physics Magazine titled , as well as Physics.org titled

Abstract from the Physical Review Letters

Luminescent conjugated polymers are organic semiconductors possessing unique electrical and optical properties. Luminescent polymers have been extensively investigated because of their potential applications in light sources and display devices. Here, we provide the first evidence that a luminescent polymer is also a strong emitter of free electrons and a source of new light. Vivid green light flashes have been observed from a red-emitting polymer 𝑝−𝑛 junction under a large reverse bias. The 𝑝−𝑛 junctions have a planar configuration, revealing that the green light flashes are emitted into free space, far beyond the confines of electrodes. Moreover, the green flashes can be strongly distorted by a permanent magnet placed nearby, generating a light show resembling an aurora. Like the aurora, the green light flashes are caused by charged particles. By applying a known transverse magnetic field to bend the flashes into circular arcs, a charge to mass ratio is determined for the charged particles. The auroralike green light coincides with the formation of electrical trees in the 𝑛-doped region of the junction. We postulate that the green light is caused by field-emitted electrons exciting an unknown organic vapor released in the treeing process.