Role of electronic localization in the phosphorescence of iridium sensitizing dyes

In this work we present a systematic study of three representative iridium dyes, namely, Ir(ppy)3, FIrpic and PQIr, which are commonly used as sensitizers in organic optoelectronic devices. We show that electronic correlations play a crucial role in determining the excited-state energies in these systems, due to localization of electrons on Ir d orbitals. Electronic localization is captured by employing hybrid functionals within time-dependent density-functional theory (TDDFT) and with Hubbard-model corrections within the delta-SCF approach. The performance of both methods are studied comparatively and shown to be in good agreement with experiment. The Hubbard-corrected functionals provide further insight into the localization of electrons and on the charge-transfer character of excited-states. The gained insight allows us to comment on envisioned functionalization strategies to improve the performance of these systems. Complementary discussions on the delta-SCF method are also presented in order to fill some of the gaps in the literature.Comment: 15 pages, 14 figure

Cross-correlation of WMAP7 and the WISE Full Data Release

We measured the cross-correlation of the Wilkinson Microwave Anisotropy Probe (WMAP) 7 year temperature map and the full sky data release of the Wide-field Infrared Survey Explorer (WISE) galaxy map. Using careful mapmaking and masking techniques we find a positive cross-correlation signal. The results are fully consistent with a Lambda-CDM Universe, although not statistically significant. Our findings are robust against changing the galactic latitude cut from |b|>10 to |b|>20 and no color dependence was detected when we used WMAP Q, V or W maps. We confirm higher significance correlations found in the preliminary data release. The change in significance is consistent with cosmic variance.Comment: 5 pages, 4 figures, Accepted for publication in MNRAS Letter