Environmental stability of high-mobility indium-oxide based transparent electrodes
Large-scale deployment of a wide range of optoelectronic devices, including solar cells, critically depends on the long-term stability of their front electrodes. Here, we investigate the performance of Sn-doped In2O3 (ITO), H-doped In2O3 (IO:H), and Zn-doped In2O3 (IZO) electrodes under damp heat (DH) conditions (85 degrees C, 85% relative humidity). ITO, IO: H capped with ITO, and IZO show high stability with only 3%, 9%, and 13% sheet resistance (Rs) degradation after 1000 h of DH, respectively. For uncapped IO: H, we find a 75% Rs degradation, due to losses in electron Hall mobility (mu(Hall)). We propose that this degradation results from chemisorbed OH-or H2O-related species in the film, which is confirmed by thermal desorption spectroscopy and x-ray photoelectron spectroscopy. While mu(Hall) strongly degrades during DH, the optical mobility (mu(optical)) remains unchanged, indicating that the degradation mainly occurs at grain boundaries. (C) 2015 Author(s). All article content, except where otherwise noted, is licensed under a Creative Commons Attribution 3.0 Unported License.