Aqueous Solution‑Processed Vanadium Oxide for Efficient Hole Injection Interfacial Layer in Organic Light‑Emitting Diode
Abstract
Solution‑processing techniques have effectively promoted low‑cost and large‑scale manufacturing of organic light‑emitting diodes (OLEDs). An ecofriendly process is demonstrated here to obtain aqueous solution‑processed vanadium oxide (s‑VOx) for effective hole injection interfacial layer (HIL) by using commercial V2O5 powders. Atomic force microscopy and X‑ray photoelectron spectroscopy measurements show that s‑VOx exhibits superior film morphology and non‑stoichiometry with slight oxygen deficiency which account for exceptional electronic properties in tailoring hole injection. With tris(8‑hydroxy‑quinolinato)aluminum as emitter, s‑VOx‑based OLED gives a maximum luminous efficiency of 6.4 cd A−1 and power efficiency of 4.1 lm W−1, which are comparable to those (6.1 cd A−1 and 3.6 lm W−1) of vacuum thermally deposited VOx‑based counterpart. The current versus voltage characteristics and impedance spectroscopy of hole‑only devices elucidate that s‑VOx possesses robust hole injection capacity and thereby promotes the OLED performance. Our results pave an alternative approach for broadening VOx application with solution process and accelerating OLED development.
- Publication:
-
Physica Status Solidi Applied Research
- Pub Date:
- June 2018
- DOI:
- 10.1002/pssa.201800047
- Bibcode:
- 2018PSSAR.21500047Z