High-Efficiency and Long-Lifetime Fluorescent Blue Organic-Emitting Device

摘要

In this paper, We have demonstrated a blue fluorescent organic light-emitting device (OLED) with a current efficiency of 19.2 cd/A at 100 cd/m~2, an estimated half-lifetime of 15611 hours at an initial luminance of 1000 cd/m~2, and a voltage of 4.9 V at 20 mA/cm~2 with a high electron mobility electron transport layer (ETL) material and high efficiency dopant material. The external quantum efficiency (EQE) in this optimized OLED is 8.32%, which is very close to the theoretical limit. Carrier balance condition is achieved due to the incorporation of the high mobility ETL, bis(10-hydroxyben-zo[h]quinolinato)beryllium (Bebq2), which can not only effectively increase the current efficiency and elongate the operation lifetime, but also reduce the driving voltage and increase the power efficiency. The EML consisted of 4,4'-bis[2-(4-(N,N-diphenylamino)phenyl)vinyl]biphenyl (DPAVBi) as the blue dopant and 9,10-bis(2'-naphthyl) anthracene (ADN) as the matrix. We found that the dopant concentration of DPAVBi did not affect the mobility value of the EML which is consistent with the J-V characteristics. Besides, although it is believed the bulk ADN is a kind of HTL materials, we found the electron mobility of ADN is one order of magnitude higher than its hole mobility in our blue OLEDs.