We report on a combined X-ray and UV photoemission spectroscopy study (XPS and UPS) of organicinorganic perovskites prepared from a solution of lead chloride (PbCl 2 ) and methylammonium iodide (CH 3 NH 3 I). The XPS intensities are consistent with a pure iodide perovskite (CH 3 NH 3 PbI 3 ), with no detectable chloride left. However, we found that the elimination of chloride results in residual methylamine molecules (CH 3 NH 2 ) trapped within the perovskite crystal lattice. Furthermore, we show that vacuum annealing or sputtering induce the formation of a thin PbI 2 layer at the crystal surface which acts as a surface barrier blocking electron transfer from the underlying perovskite film.

Current voltage measurement of three different PEDOT:PSS printed lines Figure S1. Current-voltage characteristics of all three different PEDOT:PSS printed lines. Inset (a) optical micrograph and (b) thickness profiles of the printed lines.

We present a versatile apparatus for the study of ferromagnetic surfaces, which combines spin-polarized photoemission and inverse photoemission spectroscopies. Samples can be grown by molecular beam epitaxy and analyzed in situ. Spin-resolved photoemission spectroscopy analysis is done with a hemispherical electron analyzer coupled to a 25 kV-Mott detector. Inverse photoemission spectroscopy experiments are performed with GaAs crystals as spin-polarized electron sources and a UV bandpass photon detector. As an example, measurements on the oxygen passivated Fe(100)-p(1×1)O surface are presented.

C molecules coupled to metals form hybrid systems exploited in a broad range of emerging fields, such as nanoelectronics, spintronics, and photovoltaic solar cells. The electronic coupling at the C/metal interface plays a crucial role in determining the charge and spin transport in C-based devices; therefore, a detailed understanding of the interface electronic structure is a prerequisite to engineering the device functionalities. Here, we compare the electronic and structural properties of C monolayers interfaced with Fe(001) and oxygen-passivated Fe(001)-p(1 × 1)O substrates. By combining scanning tunneling microscopy and spectroscopy, Auger electron spectroscopy, photoemission and inverse photoemission spectroscopies, we are able to elucidate the striking effect of oxygen on the interaction between Fe(001) and C. Upon C deposition on the oxygen-passivated surface, the oxygen layer remains buried at the C/Fe(001)-p(1 × 1)O interface, efficiently decoupling the fullerene film from the metallic substrate. Tunneling and photoemission spectroscopies reveal the presence of well-defined molecular resonances for the C/Fe(001)-p(1 × 1)O system, with a large HOMO-LUMO gap of about 3.4 eV. On the other hand, for the C/Fe(001) interface, a strong hybridization between the substrate states and the C orbitals occurs, resulting in broader molecular resonances.

PSS electrode, thus impeding the efficient charge extraction and limiting device photocurrent.