Influence of Fermi Level Alignment with Tin Oxide on the Hysteresis of Perovskite Solar Cells.

We tune the Fermi level alignment between the SnO electron transport layer (ETL) and Cs(FAMA)Pb(IBr) and highlight that this parameter is interlinked with current-voltage hysteresis in perovskite solar cells (PSCs). Furthermore, thermally stimulated current measurements reveal that the depth of trap states in the ETL or at the ETL-perovskite interface correlates with Fermi level positions, ultimately linking it to the energy difference between the Fermi level and conduction band minimum. In the presence of deep trap states, charge accumulation and recombination at the interface are promoted, affecting the charge collection efficiency adversely, which increases the hysteresis of PSCs.

Directional Charge-Carrier Transport in Oriented Benzodithiophene Covalent Organic Framework Thin Films.

Charge-carrier transport in oriented COF thin films is an important factor for realizing COF-based optoelectronic devices. We describe how highly oriented electron-donating benzodithiophene BDT-COF thin films serve as a model system for a directed charge-transport study. Oriented BDT-COF films were deposited on different electrodes with excellent control over film roughness and topology, allowing for high-quality electrode-COF interfaces suitable for device fabrication.

The Influence of Water Vapor on the Stability and Processing of Hybrid Perovskite Solar Cells Made from Non-Stoichiometric Precursor Mixtures.

We investigated the influence of moisture on methylammonium lead iodide perovskite (MAPbI ) films and solar cells derived from non-stoichiometric precursor mixtures. We followed both the structural changes under controlled air humidity through in situ X-ray diffraction, and the electronic behavior of devices prepared from these films. A small PbI excess in the films improved the stability of the perovskite compared to stoichiometric samples.

Hybrid Perovskite/Perovskite Heterojunction Solar Cells.

Recently developed organic-inorganic hybrid perovskite solar cells combine low-cost fabrication and high power conversion efficiency. Advances in perovskite film optimization have led to an outstanding power conversion efficiency of more than 20%. Looking forward, shifting the focus toward new device architectures holds great potential to induce the next leap in device performance.

Recycling Perovskite Solar Cells To Avoid Lead Waste.

Methylammonium lead iodide (MAPbI3) perovskite based solar cells have recently emerged as a serious competitor for large scale and low-cost photovoltaic technologies. However, since these solar cells contain toxic lead, a sustainable procedure for handling the cells after their operational lifetime is required to prevent exposure of the environment to lead and to comply with international electronic waste disposal regulations. Herein, we report a procedure to remove every layer of the solar cells separately, which gives the possibility to selectively isolate the different materials.

Enantioselective synthesis of syn- and anti-1,3-aminoalcohols via β-aminoketones and subsequent reduction/dynamic kinetic asymmetric transformation.

β-Aminoketones obtained from imines in an organocatalytic Mannich reaction were transformed to enantio- and diastereomerically pure 1,3-aminoalcohols with two stereogenic centers via a combined reduction/dynamic kinetic asymmetric transformation. Both syn and anti diastereomers were obtained in high yield, dr, and ee.