文摘
An organic light-emitting device was fabricated on a commercial atomic force microscopy (AFM) probe having a pyramidal tip by a lithography-free vacuum thermal evaporation (VTE) process. The line-of-sight molecular transport characteristic of VTE results in controlled thicknessvariation across the nonplanar substrate, such that localized current injection occurs at the tip region. Furthermore, the high curvature of theAFM tip vertex concentrates the electric field, causing highly localized bipolar charge injection, accompanied by photon emission from aregion less than a micrometer across. This light source exhibits a range of features potentially attractive for applications such as probe-basedoptical microscopy, nanoscale light sensing, and chemical detection.