An organic light emitting device (OLED) has a thick (100 to 250 nanometers)
porphyrin buffer layer between the anode and the luminescent region. The
thick porphyrin buffer layer in the OLED results in a small increase in
device operating voltage, reduces the possibility of OLED shorting and can
improve color purity in blue emitting OLEDs due to its significant optical
absorption in the red range.
