Fast Sputter-Deposition of High-Performance MoO3/Ag/MoO3 Transparent Electrodes on PET for Flexible Printed Photovoltaics and Light-Emitting Diodes
(Room Exhibit Hall A)
30 Apr 19
2:30 PM
-
4:00 PM
Indium-tin-oxide (ITO) is the dominant transparent electrode for flexible photovoltaics and light- emitting diodes on PET substrate. Apart from its high cost, the PET/ITO sheet resistance is relatively high (~50 Ω/sq.) and increases dramatically upon substrate bending. Dielectric/metal/dielectric (DMD) electrodes have a competitive advantage over ITO, offering very low sheet resistance - even when deposited without substrate heating - and much better mechanical stability. MoO3 is a prominent hole-transport material used in organic optoelectronics and PV. MoO3/Ag/MoO3 DMD electrodes were deposited in the literature on glass and PET by evaporation, with very low deposition rates for MoO3 (~0.1 nm/sec) and best sheet resistance on PET ~13 Ω/sq. with 66% average visible transparency. Here we present sputter-deposited MoO3/Ag/MoO3 and MoO3/Au/MoO3 electrodes on PET at MoO3 deposition rates up to ~10 times the ones achieved by evaporation, utilizing a ceramic MoOx sputtering target with optimized DC deposition processing parameters. DMD performance surpasses what is currently achieved in the literature with MoO3 dielectric. Sheet resistance of 7 Ω/sq. and average transparency of 67% (including the PET substrate) in the 400-800nm range is achieved for electrodes employing Ag. With Au, 18 Ω/sq. with 75.5% transparency is achieved. The developed DMDs have higher figure-of-merit than most commercially available ITO electrodes on PET.