Jiwon Byun

Micropollution is an ever‐increasing concern to human health and wildlife caused by population growth, industrialization, and intensive agriculture. An example of such micropollutants are natural and synthetic estrogen hormones. They are found everywhere in the aquatic environment at very low but dangerous concentrations. In this article, we demonstrate a supramolecular design principle for adsorption of such low‐concentrated estrogens onto tailored superparamagnetic iron oxide nanoparticles (SPIONs) enabling efficient magnetic water cleaning. We facilitate the adsorption by tuning the SPION surface with a binary self‐assembled monolayer (SAM) composed of two phosphonic acid derivatives: one serving as hydrophobic interaction site and the other improving water dispersibility of the system. Next to validating the concept in real river water, we conclude the demonstration of our nanomaterials by unveiling the estrogen‐SAM interaction at dilute conditions via synergistic combination of model systems, characterization techniques, and simulation. We experimentally deduce tight binding of estrogens combined with simulations that identify different, dynamic adsorption motifs at molecular space and time scale including a rare intercalation state, in which the hydrophobic pollutants minimize their contact to water. We believe that beyond our materials, these insights on the pollutant‐adsorbent interface underline the importance and potential of rational, molecular‐scale design of nano‐adsorbents.

Ordered one dimensional perovskite single-crystal nanowire arrays, which combine high surface-to-volume ratios, directional charge transport, and mechanical flexibility, are typically prepared through solution or vapor phase techniques using templates of silicon, polydimethylsiloxane, photoresist, or aluminum oxide to control crystal growth. However, the size limits of these templates restrict the scalability of the arrays. Here, we introduce a dynamic template-assisted coating strategy that integrates blade coating to address this limitation. The method enables deposition of nanowire arrays on substrates with an area 12 times larger than the template. Incorporating a fluorinated passivating agent into the precursor suppresses surface defect formation and improves structural quality. Photodetectors based on MAPbBr ₃ arrays achieve a detectivity of 3.9 × 10 ¹⁴ Jones, a linear dynamic range of 160.3 dB, and a responsivity of 1660 A W ^-1 , and retain 90.3% of their photocurrent after 300 h at 85% relative humidity without encapsulation.

Ligand engineering is an effective method to reduce defects in perovskite solar cells (PSCs) and to enhance efficiency.

Perovskite-organic tandem solar cells (P-O-TSCs) hold substantial potential to surpass the theoretical efficiency limits of single-junction solar cells. However, their performance is hampered by non-ideal interconnection layers (ICLs). Especially in n-i-p configurations, the incorporation of metal nanoparticles negatively introduces serious parasitic absorption, which alleviates photon utilization in organic rear cell and decisively constrains the maximum photocurrent matching with front cell. Here, we demonstrate an efficient strategy to mitigate optical losses in Au-embedded ICLs by tailoring the shape and size distribution of Au nanoparticles via manipulating the underlying surface property. Achieving fewer, smaller, and more uniformly spherical Au nanoparticles significantly minimizes localized surface plasmon resonance absorption, while maintaining efficient electron-hole recombination within ICLs. Consequently, optimized P-O-TSCs combining CsPbI₂Br with various organic cells benefit from a substantial current gain of >1.5 mA/cm² in organic rear cells, achieving a champion efficiency of 25.34%. Meanwhile, optimized ICLs contribute to improved long-term device stability.