A universal solution processed interfacial bilayer enabling ohmic contact in organic and hybrid optoelectronic devices
byJoel Troughton, Marios Neophytou, Nicola Gasparini, Akmaral Seitkhan, Furkan Halis Isikgor, Xin Song, Yen-Hung Lin, Tong Liu, Hendrik Faber, Emre Yengel, Jan Kosco, Marek F. Oszajca, Benjamin Hartmeier, Michael Rossier, Norman A. Lüchinger, Leonidas Tsetseris, Henry J. Snaith, Stefaan De Wolf, Thomas D. Anthopoulos, Iain McCulloch, Derya Baran
Troughton, J., Neophytou, M., Gasparini, N., Seitkhan, A., Isikgor, F. H., Song, X., ... & Kosco, J. (2020). A universal solution processed interfacial bilayer enabling ohmic contact in organic and hybrid optoelectronic devices. Energy & Environmental Science.
Optoelectronic devices typically require low-resistance ohmic contacts between the optical active layers and metal electrodes. Failure to make such a contact often results in a Schottky barrier which inhibits charge extraction and, in turn, reduces device performance. Here, we introduce a universal solution processable metal-oxide/organic interfacial bilayer which forms a near-perfect ohmic contact between both organic and inorganic semiconductors and metals. This bilayer comprises a Nb-doped TiO2 metal oxide with enhanced electron mobility and reduced trap density compared to pristine TiO2, in combination with a metal-chelating organic molecule to make an intimate electrical contact with silver metallic electrodes. Using this universal interfacial bilayer, we demonstrate substantial efficiency improvements in organic solar cells (from 9.3% to 12.6% PCE), light emitting diodes (from 0.6 to 2.2 cd W−1) and transistors (from 19.7 to 13.9 V threshold voltage). In particular, a boost in efficiency for perovskite solar cells (from 18.7% up to 20.7% PCE) with up to 83% fill factor is achieved with no-operational lifetime loss for at least 1000 hours under continuous, full-spectrum illumination.