We demonstrate highly efficient inverted bottom-emission organic light-emitting diodes (IBOLEDs) by using cesium hydroxide (CsOH) doped tris-(8-hydroxyquinoline) aluminum (Alq3) as the electron injection layer on indium tin oxide cathode, which could significantly enhance the electron injection, resulting in a large increase in luminance and efficiency. The maximum luminance, current efficiency, and power efficiency reach 21000cdcm2, 6.5cdA, and 3.5lmW, respectively, which are 40%–50% higher in efficiency than that of IBOLEDs with cesium carbonate (Cs2CO3) doped Alq3 as the electron injection layer, where the efficiencies are only 4.5cdA and 2.2lmW. Our results indicate that CsOH doped Alq3 should be an effective electron injection layer on a wide range of electrodes to fabricate high performance OLEDs.

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