Buffer-modified C60/pentacene as organic charge generation layer based on Al and MoO3

Abstract

We demonstrate tandem organic light-emitting diodes (TOLEDs) with excellent performance using Al and MoO3 buffer-modified C60/pentacene as charge generation layer (CGL). Al and MoO3 were used as the electron and hole injection layers of C60/pentacene CGL, respectively. Green phosphorescence TOLEDs with the structure of ITO/NPB/mCP:Ir(ppy)3/TPBi/Al/C60/pentacene/MoO3/NPB/mCP:Ir(ppy)3/TPBi/Cs2CO3/Al were fabricated. The results show that the inserted Al and MoO3 can effectively increase the charge injection capacity of organic CGL, resulting the improvement of luminance and current efficiency of TOLEDs. The turn-on voltage of TOLEDs is much lower than that of single-unit device, and the current efficiency is more than 2 times larger than that of the single-unit device. TOLEDs can exhibit excellent photoelectric performance when the thicknesses of Al, C60, pentacene and MoO3 are 3 nm, 15 nm, 25 nm and 1 nm, respectively. The maximum luminance and current efficiency are 7 920.0 cd/m2 and 16.4 cd/A, respectively. This work is significant to build new CGL structures for realizing high-performance TOLEDs.