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Hydrogen-doped In2O3 (In2O3:H) is highly conductive while maintaining extraordinary transparency, thus making it a very attractive material for applications in optoelectronic devices such as (multijunction) solar cells or light-emitting devices. However, the corresponding metal/In2O3:H contacts may exhibit undesirably high resistances, significantly deteriorating device performance. To gain insight into the underlying efficiency-limiting mechanism, hard X-ray photoelectron spectroscopy is employed to in-situ monitor annealing-induced changes in the chemical structure of the Ag/In2O3:H interface system that is further complemented by ex-situ electron microscopy analyses and contact resistance measurements. The observed evolution of the Ag- and In-related photoelectron line intensities can be explained by significant intermixing across the Ag/In2O3:H interface. The corresponding lineshape broadening of the Ag 3d spectra is attributed to the formation of Ag2O and AgO, which becomes significant at temperatures above approximately 160 °C. However, after annealing to 300 °C, instead of the formation of an insulating AgOx interfacial layer, it is found i) In to be rather homogeneously distributed in the complete Ag/In2O3:H stack, ii) Ag diffusing into the In2O3:H, and iii) an improvement of the contact resistance rather than its often-reported deterioration., Helmholtz‐Association, Robert Bosch Stiftung http://dx.doi.org/10.13039/501100001646, National Natural Science Foundation of China http://dx.doi.org/10.13039/501100001809, Peer Reviewed

Hybrid organic/inorganic materials have emerged as promising thermoelectric (TE) materials since they inherit the individual strengths of each component, enabling rational materials design with enhanced TE performance. The doping of hybrid TE materials via post-treatment processes is used to improve their performance, but there is still an incomplete understanding of the elicited effects. Here, the impact of different doping methods on the thin film TE performance of p-type Te/poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) and n-type Ag2Te/PEDOT:PSS hybrid materials is investigated. Primary doping through acid–base and charge transfer processes using H2SO4 and tetrakis(dimethylamino)ethylene, respectively, and the effects of secondary doping using ethylene glycol is examined. Through a combination of Hall effect measurements, hard X-ray photoelectron spectroscopy, and Raman spectroscopy, variations in the charge carrier concentration, mobility, and overall TE performance are related to the morphological and chemical structure of the hybrid materials. This study provides an improved understanding of the effects that different post-treatments have on hybrid materials and shows that the impact of these post-treatments on pure PEDOT:PSS does not always apply to hybrid systems. These new insights into post-treatment effects on hybrid materials is expected to facilitate further enhancement of their performance as electronic materials in general and thermoelectric materials in particular., Peer Reviewed

Copper sulfide shows some unique physico-chemical properties that make it appealing as a cathode active material (CAM) for solid-state batteries (SSBs). The most peculiar feature of the electrode reaction is the reversible formation of µm-sized Cu crystals during cycling, despite its large theoretical volume change (75%). Here, the dynamic microstructural evolution of CuS cathodes in SSBs is studied using in situ synchrotron X-ray tomography. The formation of µm-sized Cu within the CAM particles can be clearly followed. This process is accompanied by crack formation that can be prevented by increasing the stack pressure from 26 to 40 MPa. Both the Cu inclusions and cracks show a preferential orientation perpendicular to the cell stack pressure, which can be a result of a z-oriented expansion of the CAM particles during lithiation. In addition, cycling leads to a z-oriented reversible displacement of the cathode pellet, which is linked to the plating/stripping of the Li counter electrode. The pronounced structural changes cause pressure changes of up to 6 MPa within the cell, as determined by operando stack pressure measurements. Reasons for the reversibility of the electrode reaction are discussed and are attributed to the favorable combination of soft materials., China Scholarship Council http://dx.doi.org/10.13039/501100004543, NASEBER, KAROFEST, Bundesministerium für Bildung und Forschung http://dx.doi.org/10.13039/501100002347, Deutsches Elektronen‐Synchrotron http://dx.doi.org/10.13039/501100001647, Peer Reviewed

The co-intercalation of solvent molecules along with Na+ into the crystal lattice of electrode materials is an undesired process in sodium batteries. An exception is the intercalation of ether solvated alkali ions into graphite, a fast and highly reversible process. Here, reversible co-intercalation is shown to also be possible for other layered materials, namely titanium disulfide. Operando X-ray diffraction and dilatometry are used to demonstrate different storage mechanisms for different electrolyte solvents. Diglyme is found to co-intercalate into the TiS2 leading to a change in the voltage profile and an increase in the interlayer spacing (≈150%). This behavior is different compared to other solvents, which expand much less during Na storage (24% for tetrahydrofuran [THF] and for a carbonate mixture). For all solvents, specific capacities (2nd cycle) exceed 250 mAh g−1 whereas THF exhibited the best stability after 100 cycles. The solvent co-intercalation is rationalized by density functional theory and linked to the stability of the solvation shells, which is largest for diglyme. Finally, the TiS2 electrode with diglyme electrolyte is paired with a graphite electrode to realize the first proof-of-concept solvent co-intercalation battery, that is, a battery with two electrodes that both rely on reversible co-intercalation of solvent molecules., European Research Council http://dx.doi.org/10.13039/501100000781, Peer Reviewed

In this review, we present important concepts to describe inorganic–organic interfaces in hybrid solar cells. We discuss the formation of hybrid interfaces, provide an introduction to the ground-state electronic structure of the individual components, and detail the overall electronic landscape after combining into a hybrid material for different relevant cases. We then explore the impact of hybrid interfaces on photophysical processes that are crucial for the photovoltaic performance of hybrid solar cells. Within this framework, we discuss methods for hybrid interface modification toward the optimization of hybrid solar cells, such as doping, the application of interlayers, and morphological control., Helmholtz-Gemeinschafthttps://doi.org/10.13039/501100001656, Peer Reviewed