Inclusion of 2d transition metal dichalcogenides in perovskite inks and their influence on solar cell performance

Funding Information: Acknowledgments: V.N. wishes to thank the support from the ERC 3D2DPrint CoG Grant. The authors gratefully acknowledge the project Best4U—“Tecnologia per celle solari bifacciali ad alta Efficienza a 4 terminali per utility scale”. The authors are grateful to the “Progetto Tecnopolo per la Medicina di precisione, Deliberazione della Giunta Regionale n. 2117 del 21 November 2018”.Organic–inorganic hybrid perovskite materials have raised great interest in recent years due to their excellent optoelectronic properties, which promise stunning improvements in photovoltaic technologies. Moreover, two-dimensional layered materials such as graphene, its derivatives, and transition metal dichalcogenides have been extensively investigated for a wide range of electronic and optoelectronic applications and have recently shown a synergistic effect in combination with hybrid perovskite materials. Here, we report on the inclusion of liquid-phase exfoliated molybdenum disulfide nanosheets into different perovskite precursor solutions, exploring their influence on final device performance. We compared the effect of such additives upon the growth of diverse perovskites, namely CH3NH3PbI3 (MAPbI3 ) and triple-cation with mixed halides Csx (MA0.17FA0.83 )(1−x)Pb (I0.83Br0.17 )3 perovskite. We show how for the referential MAPbI3 materials the addition of the MoS2 additive leads to the formation of larger, highly crystalline grains, which result in a remarkable 15% relative improvement in power conversion efficiency. On the other hand, for the mixed cation– halide perovskite no improvements were observed, confirming that the nucleation process for the two materials is differently influenced by the presence of MoS2 .publishersversionpublishe

MXene-induced nonradiative energy transfer

Since their discovery in 2011, MXenes have risen to prominence for energy storage, electromagnetic shielding, and optoelectronics. Yet, the nonradiative energy transfer properties of this family of 2D materials remain elusive, which may have implications in optoelectronics, photovoltaics and biosensing. Here, we use single-molecule fluorescence confocal microscopy and DNA origami nanopositioners to investigate, for the first time, the distance-dependent energy transfer of an organic emitter (ATTO 542) placed on transparent thin films made of spincast Ti3C2Tx flakes. We propose a specific immobilization chemistry for DNA origami nanostructures based on glycine-MXene interaction, allowing us to precisely control their orientation on the surface. Each DNA origami structure is designed to carry a single dye molecule at predetermined heights. Our findings reveal that when the dye is located at distances of 1 nm < d < 8 nm from the surface, the fluorescence is quenched following a distance dependence of d-3. This is in agreement with the Förster-type mechanism of energy transfer in transparent conductors at the bulk level. 50% of energy transfer efficiency is reached at 2.7 nm (d0). MXenes could therefore be used as short-distance spectroscopic nanorulers, sensitive at a distance regime that common energy transfer tools cannot access

MXene functionalized collagen biomaterials for cardiac tissue engineering driving iPSC-derived cardiomyocyte maturation

Electroconductive biomaterials are gaining significant consideration for regeneration in tissues where electrical functionality is of crucial importance, such as myocardium, neural, musculoskeletal, and bone tissue. In this work, conductive biohybrid platforms were engineered by blending collagen type I and 2D MXene (Ti3C2Tx) and afterwards covalently crosslinking; to harness the biofunctionality of the protein component and the increased stiffness and enhanced electrical conductivity (matching and even surpassing native tissues) that two-dimensional titanium carbide provides. These MXene platforms were highly biocompatible and resulted in increased proliferation and cell spreading when seeded with fibroblasts. Conversely, they limited bacterial attachment (Staphylococcus aureus) and proliferation. When neonatal rat cardiomyocytes (nrCMs) were cultured on the substrates increased spreading and viability up to day 7 were studied when compared to control collagen substrates. Human induced pluripotent stem cell-derived cardiomyocytes (iPSC-CMs) were seeded and stimulated using electric-field generation in a custom-made bioreactor. The combination of an electroconductive substrate with an external electrical field enhanced cell growth, and significantly increased cx43 expression. This in vitro study convincingly demonstrates the potential of this engineered conductive biohybrid platform for cardiac tissue regeneration.</p