E. H. (2022). Quantum-size-tuned heterostructures enable efficient and stable inverted perovskite solar cells. Nature Photonics.

Many of the best-performing perovskite photovoltaic devices make use of 2D/3D interfaces, which improve efficiency and stability – but it remains unclear how the conversion of 3D-to-2D perovskite occurs and how these interfaces are assembled. Here, we use in situ Grazing-Incidence Wide-Angle X-Ray Scattering to resolve 2D/3D interface formation during spin-coating. We observe progressive dimensional reduction from 3D to n = 3 → 2 → 1 when we expose (MAPbBr3)0.05(FAPbI3)0.95 perovskites to vinylbenzylammonium ligand cations. Density functional theory simulations suggest ligands incorporate sequentially into the 3D lattice, driven by phenyl ring stacking, progressively bisecting the 3D perovskite into lower-dimensional fragments to form stable interfaces. Slowing the 2D/3D transformation with higher concentrations of antisolvent yields thinner 2D layers formed conformally onto 3D grains, improving carrier extraction and device efficiency (20% 3D-only, 22% 2D/3D). Controlling this progressive dimensional reduction has potential to further improve the performance of 2D/3D perovskite photovoltaics.

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Drug-conjugated gold nanoparticles (GNPs), which are generally constructed with many molecules of thiol-terminated polyethylene glycol (PEG)-drug decorated on their surfaces via a thiol-Au covalent bond, are promising and efficient nanoprodrugs. However, because of the exposure of the hydrophobic drug molecules on the surface of the conjugate, in vivo stability, opsonization, and subsequent inefficient therapy become the main issues of this system. To solve these problems without complicating the structures of gold conjugates, herein we propose a method to change the relative position of PEG and the drug. A novel gold conjugate (GNP-NHN═Dox-mPEG) with doxorubicin (Dox) shielded by PEGylation on the surface of GNPs is designed. It demonstrates improved solubility, stability, and dispersion and achieves a two-step stimulus-responsive drug release in response to an acidic environment in lysosomes and then esterase in the cytoplasm. This unique manner of release enables the cytoplasm to act as a reservoir for sustained drug delivery into the nucleus to improve antitumor efficacy in vivo. The intratumoral drug concentrations of the conjugate reach 14.4 ± 1.4 μg/g at 8 h, a two-fold increase in the drug concentration compared with that of the doxorubicin hydrochloride group. This molecular design and regulation approach is facile but important in modulating the in vivo performance of nanovehicles and demonstrates its vital potential in developing effective nanoparticle-based drug delivery agents.