Cesium azide (CsN 3) is confirmed to be decomposed during thermal evaporation. Only Cs could be deposited on tris(8-hydroxyquinolinato)aluminum (Alq 3) and n-type doping is easily achieved. Organic light-emitting devices with CsN 3 show highly improved current density-luminance- voltage characteristics compared to the control device without CsN 3. To understand the origin of the improvements, in situ x-ray and UV photoemission spectroscopy measurements were carried out and a remarkable reduction in electron injection barrier is verified with successive deposition of Al on CsN 3 on Alq 3. CsN 3 has a potential as alternative to doping the electron transport layer by replacing the direct deposition of alkali metals.
Bibliographical noteFunding Information:
This work was supported by Brain Korea 21 (BK21) project of the ministry of Education, Science and Technology and by a research project of the National Research Foundation of Korea. (Grant No. 2011-0004748).
All Science Journal Classification (ASJC) codes
- Physics and Astronomy (miscellaneous)