TY  - JOUR
A1  - Zu, Fengshuo
A1  - Amsalem, Patrick
A1  - Egger, David A.
A1  - Wang, Rongbin
A1  - Wolff, Christian Michael
A1  - Fang, Honghua
A1  - Loi, Maria Antonietta
A1  - Neher, Dieter
A1  - Kronik, Leeor
A1  - Duhm, Steffen
A1  - Koch, Norbert
T1  - Constructing the Electronic Structure of CH3NH3PbI3 and CH3NH3PbBr3 Perovskite Thin Films from Single-Crystal Band Structure Measurements
JF  - The journal of physical chemistry letters
N2  - Photovoltaic cells based on halide perovskites, possessing remarkably high power conversion efficiencies have been reported. To push the development of such devices further, a comprehensive and reliable understanding of their electronic properties is essential but presently not available. To provide a solid foundation for understanding the electronic properties of polycrystalline thin films, we employ single-crystal band structure data from angle-resolved photoemission measurements. For two prototypical perovskites (CH3NH3PbBr3 and CH3NH3PbI3), we reveal the band dispersion in two high-symmetry directions and identify the global valence band maxima. With these benchmark data, we construct "standard" photoemission spectra from polycrystalline thin film samples and resolve challenges discussed in the literature for determining the valence band onset with high reliability. Within the framework laid out here, the consistency of relating the energy level alignment in perovskite-based photovoltaic and optoelectronic devices with their functional parameters is substantially enhanced.
Y1  - 2019
U6  - https://doi.org/10.1021/acs.jpclett.8b03728
SN  - 1948-7185
VL  - 10
IS  - 3
SP  - 601
EP  - 609
PB  - American Chemical Society
CY  - Washington
ER  - 
TY  - JOUR
A1  - Wolff, Christian Michael
A1  - Frischmann, Peter D.
A1  - Schulze, Marcus
A1  - Bohn, Bernhard J.
A1  - Wein, Robin
A1  - Livadas, Panajotis
A1  - Carlson, Michael T.
A1  - Jäckel, Frank
A1  - Feldmann, Jochen
A1  - Würthner, Frank
A1  - Stolarczyk, Jacek K.
T1  - All-in-one visible-light-driven water splitting by combining nanoparticulate and molecular co-catalysts on CdS nanorods
JF  - Nature Energy
N2  - Full water splitting into hydrogen and oxygen on semiconductor nanocrystals is a challenging task; overpotentials must be overcome for both half-reactions and different catalytic sites are needed to facilitate them. Additionally, efficient charge separation and prevention of back reactions are necessary. Here, we report simultaneous H-2 and O-2 evolution by CdS nanorods decorated with nanoparticulate reduction and molecular oxidation co-catalysts. The process proceeds entirely without sacrificial agents and relies on the nanorod morphology of CdS to spatially separate the reduction and oxidation sites. Hydrogen is generated on Pt nanoparticles grown at the nanorod tips, while Ru(tpy)(bpy)Cl-2-based oxidation catalysts are anchored through dithiocarbamate bonds onto the sides of the nanorod. O-2 generation from water was verified by O-18 isotope labelling experiments, and time-resolved spectroscopic results confirmed efficient charge separation and ultrafast electron and hole transfer to the reaction sites. The system demonstrates that combining nanoparticulate and molecular catalysts on anisotropic nanocrystals provides an effective pathway for visible-light-driven photocatalytic water splitting.
Y1  - 2018
U6  - https://doi.org/10.1038/s41560-018-0229-6
SN  - 2058-7546
VL  - 3
IS  - 10
SP  - 862
EP  - 869
PB  - Nature Publ. Group
CY  - London
ER  - 
TY  - JOUR
A1  - Saliba, Michael
A1  - Correa-Baena, Juan-Pablo
A1  - Wolff, Christian Michael
A1  - Stolterfoht, Martin
A1  - Phung, Thi Thuy Nga
A1  - Albrecht, Steve
A1  - Neher, Dieter
A1  - Abate, Antonio
T1  - How to Make over 20% Efficient Perovskite Solar Cells in Regular (n-i-p) and Inverted (p-i-n) Architectures
JF  - Chemistry of materials : a publication of the American Chemical Society
N2  - Perovskite solar cells (PSCs) are currently one of the most promising photovoltaic technologies for highly efficient and cost-effective solar energy production. In only a few years, an unprecedented progression of preparation procedures and material compositions delivered lab-scale devices that have now reached record power conversion efficiencies (PCEs) higher than 20%, competing with most established solar cell materials such as silicon, CIGS, and CdTe. However, despite a large number of researchers currently involved in this topic, only a few groups in the world can reproduce >20% efficiencies on a regular n-i-p architecture. In this work, we present detailed protocols for preparing PSCs in regular (n-i-p) and inverted (p-i-n) architectures with >= 20% PCE. We aim to provide a comprehensive, reproducible description of our device fabrication , protocols. We encourage the practice of reporting detailed and transparent protocols that can be more easily reproduced by other laboratories. A better reporting standard may, in turn, accelerate the development of perovskite solar cells and related research fields.
Y1  - 2018
U6  - https://doi.org/10.1021/acs.chemmater.8b00136
SN  - 0897-4756
SN  - 1520-5002
VL  - 30
IS  - 13
SP  - 4193
EP  - 4201
PB  - American Chemical Society
CY  - Washington
ER  -