Heiko Peisert | Eberhard Karls Universität Tübingen (original) (raw)

Papers by Heiko Peisert

Journal of Applied Physics, Aug 1, 2000

We present an investigation of interface properties of the hole transport material N,N′-diphenyl-... more We present an investigation of interface properties of the hole transport material N,N′-diphenyl-N,N′-bis (3-methylphenyl)–(1,1′)–biphenyl-4,4′diamine (TPD) on indium–tin oxide (ITO) and on GeS(001) using x-ray and ultraviolet photoelectron spectroscopy. On both the TPD/ITO interface and the TPD/GeS(001) heterojunction we found shifts of the vacuum level indicating a formation of an interfacial dipole barrier. We obtained a barrier for the hole injection for TPD on Ar ion sputter-cleaned ITO of 1.5 eV which is significantly higher than the commonly cited value of 0.5 eV for ozone-oxidized ITO, whereas the interface dipole barrier of 0.3 eV is in good agreement with reported data. At low coverages of TPD on ITO additional features in the C 1s core level spectra were found, which can be ascribed to a partially oxidized TPD species at the interface.

Chemistry: A European Journal, Sep 14, 2022

Journal of Physical Chemistry C, Dec 29, 2021

$Research paper thumbnail of Porphyrin-functionalization of CsPbBrI$_{2}$/SiO$_{2}$ core-shell nanocrystals enhances the stability and efficiency in electroluminescent devices$

arXiv (Cornell University), Sep 12, 2021

Wiley-VCH Verlag GmbH & Co. KGaA eBooks, Feb 13, 2006

2D semiconducting transition metal dichalcogenides (TMDCs) are highly promising materials for fut... more 2D semiconducting transition metal dichalcogenides (TMDCs) are highly promising materials for future spin- and valleytronic applications and exhibit an ultrafast response to external (optical) stimuli which is essential for optoelectronics. Colloidal nanochemistry on the other hand is an emerging alternative for the synthesis of 2D TMDC nanosheet (NS) ensembles, allowing for the control of the reaction via tunable precursor and ligand chemistry. Up to now, wet-chemical colloidal syntheses yielded intertwined/agglomerated NSs with a large lateral size. Here, we show a synthesis method for 2D mono- and bilayer MoS2 nanoplatelets with a particularly small lateral size (NPLs, 7.4 nm ± 2.2 nm) and MoS2 NSs (22 nm ± 9 nm) as a reference by adjusting the molybdenum precursor concentration in the reaction. We find that in colloidal 2D MoS2 syntheses initially a mixture of the stable semiconducting and the metastable metallic crystal phase is formed. 2D MoS2 NPLs and NSs then both undergo a ...

ACS applied electronic materials, Jan 21, 2021

BN-substituted nanographene molecules are currently the focus of interest because the substitutio... more BN-substituted nanographene molecules are currently the focus of interest because the substitution of C–C units by isoelectronic and isosteric BN units is a straightforward way of changing the elec...

Journal of Physical Chemistry C, Jul 31, 2018

Journal of Physical Chemistry C, May 24, 2018

Applied Physics A, Dec 1, 1997

A photoemission study was performed in order to obtain structural and chemical information on a s... more A photoemission study was performed in order to obtain structural and chemical information on a sulfurized InP(001) surface by using both high-resolution SXPS/XPS and polar angle scanned photoelectron diffraction (XPD). Theoretical simulations of the angular distribution curves (ADCs) were carried out on the level of single scattering cluster calculations. The ADCs of the S 2p core level of sulfur on InP(001) clearly indicate partial incorporation of the sulfur onto phosphorus lattice sites of the bulk InP structure. Persistence of sulfidic S species against UV/ozone exposure also suggests subsurface sulfur on InP(001). The sulfur-passivation may significantly reduce the amount of surface oxidation but cannot suppress it completely.

ACS Applied Materials & Interfaces, Jun 27, 2023

Applied Physics Letters, Dec 27, 2004

Occurrence and extent of chemical reactions at Cu∕ZnS(001) and In∕ZnS(001) heterojunctions have b... more Occurrence and extent of chemical reactions at Cu∕ZnS(001) and In∕ZnS(001) heterojunctions have been investigated by SL2,3 x-ray emission spectroscopy as well as photoelectron spectroscopy. With the formation of metal-sulfur bonds, spectral features originating from shallow metal d core levels (Zn3d, In4d) or valence states (Cu3d)) may appear in the SL2,3 emission spectra. Thus the x-ray emission spectroscopy was employed to detect chemical reactions at the heterojunctions, together with conventional photoelectron spectroscopy. Considerable reactions at the Cu∕ZnS(001) interface are more clearly indicated in the SL emission spectrum than in the Cu2p3∕2 or S2p core level spectra, whereas relatively confined reactions at the In∕ZnS(001) interface can only be probed in the In3d5∕2 core level spectra. The partial densities of states calculated for a reference CuInS2 on the basis of density functional theory agree well with features occurring in its SL2,3 emission spectrum.

Journal of Applied Physics, Jul 1, 2001

We have studied the molecular orientation of the commonly used organic semiconductor copper phtha... more We have studied the molecular orientation of the commonly used organic semiconductor copper phthalocyanine (CuPC) grown as thin films on the technically relevant substrates indium tin oxide, oxidized Si, and polycrystalline gold using polarization-dependent x-ray absorption spectroscopy, and compare the results with those obtained from single crystalline substrates [Au(110) and GeS(001)]. Surprisingly, the 20–50 nm thick CuPC films on the technical substrates are as highly ordered as on the single crystals. Importantly, however, the molecular orientation in the two cases is radically different: the CuPC molecules stand on the technical substrates and lie on the single crystalline substrates. The reasons for this and its consequences for our understanding of the behavior of CuPC films in devices are discussed.

Organic Electronics, Oct 1, 2017

Journal of Physics: Condensed Matter, Mar 1, 2019

Photoelectron spectroscopy was used to investigate electronic interface properties and interactio... more Photoelectron spectroscopy was used to investigate electronic interface properties and interactions of the organic semiconductors CoPc and CoPcF16 on graphene/nickel based substrates. Additional focus was put on the influence of germanium intercalation of graphene/nickel. The presented results demonstrate that germanium can decouple graphene from nickel and in this manner restore its buffer layer properties. No charge transfer from the substrate to the organic layer is observed in the germanium intercalated case, while interface related peaks in the Co 2p core level spectra indicate such charge transfer on graphene/nickel. Strong interface dipoles are found for CoPcF16 on graphene/nickel and on germanium intercalated graphene/nickel. Fluorine Auger parameters have been measured, and the results provide evidence for polarization and charge transfer screening effects of different amounts at the unlike film-substrate interfaces. The various contributions to the observed shifts are discussed.

Acta Physica Polonica A, Jun 1, 1993