“T-shaped” Carbazole Alkylammonium Cation Passivation in Perovskite Solar Cells

Incorporating alkylammonium cations atop the 3D perovskite enables effective defect passivation and significantly enhances the power conversion efficiency of perovskite solar cells. However, the diversity and durability of this passivation strategy have been limited to the ligand type and diffusion of ligands due to high reactivity. Here, we designed bulky “T-shaped” conjugated carbazole alkylammonium cations with inner π–π interaction and enlarged steric hindrance to minimize ligand diffusion while maintaining passivation effects. As verified by grazing incidence X-ray diffraction and transient absorption spectra, these “T-shaped” passivators could keep a stable intrinsic crystal phase on the perovskite surface after thermal aging. Additionally, the devices utilizing these organic semiconductor-based “T-shaped” ligands were relatively constant in series resistance and introduced higher hole mobility than the PEAI. Finally, the champion device using the “T-shaped” passivator achieved a maximum device efficiency of 25.1% with improved operational stability under 1 sun illumination

Linking Small-scale Solar Wind Properties with Large-scale Coronal Source Regions through Joint Parker Solar Probe-Metis/Solar Orbiter Observations

The solar wind measured in situ by Parker Solar Probe in the very inner heliosphere is studied in combination with the remote-sensing observation of the coronal source region provided by the METIS coronagraph aboard Solar Orbiter. The coronal outflows observed near the ecliptic by Metis on 2021 January 17 at 16:30 UT, between 3.5 and 6.3 R ⊙ above the eastern solar limb, can be associated with the streams sampled by PSP at 0.11 and 0.26 au from the Sun, in two time intervals almost 5 days apart. The two plasma flows come from two distinct source regions, characterized by different magnetic field polarity and intensity at the coronal base. It follows that both the global and local properties of the two streams are different. Specifically, the solar wind emanating from the stronger magnetic field region has a lower bulk flux density, as expected, and is in a state of well-developed Alfvénic turbulence, with low intermittency. This is interpreted in terms of slab turbulence in the context of nearly incompressible magnetohydrodynamics. Conversely, the highly intermittent and poorly developed turbulent behavior of the solar wind from the weaker magnetic field region is presumably due to large magnetic deflections most likely attributed to the presence of switchbacks of interchange reconnection origin.</p