  We fabricate OLEDs using a stable neutral {\pi} radical, BDPA, as the
emitter. There is only one electron in the singly occupied molecular orbital
(SOMO) of this open-shell molecule. This feature makes the excited state of
open-shell molecules be neither singlet nor triplet, but doublet. The key issue
of how to harvest the triplet energy in an OLED is thus bypassed, due to the
radiative decay of doublet is totally spin allowed. In the BDPA-based OLED, the
emission was confirmed to be from the electronic transition from LUMO to SOMO,
via the frontier molecular orbital analysis combined with the spectroscopy
measurements. The maximum luminance of the OLEDs is 4879 cd/m2 which is
comparable to the first reported Fluorescence-, Phosphorecence- and TADF-based
OLEDs.
