Łukasz Orzeł

Defect‐mediated recombination in oxide photoelectrodes is widely treated as an intrinsic loss pathway, yet its selective control remains largely unexplored. Here, we demonstrate that oxygen‐vacancy‐mediated recombination in ZnO can be effectively modulated through interface engineering and electrolyte‐dependent kinetics. In BiVO ₄ /ZnO, interfacial coupling promotes recombination via specific defect states, whereas incorporation of Bi ₂ S ₃ suppresses this pathway and shifts the system toward more efficient charge separation. In the presence of sulfide, the ternary Bi ₂ S ₃ /BiVO ₄ /ZnO photoanode exhibits the highest photocurrent, applied bias photon to current efficiency (ABPE), and incident photon to current efficiency (IPCE), accompanied by a transition in the intensity modulated photocurrent spectroscopy (IMPS) response toward a single dominant charge‐transfer time constant. Combined photoluminescence, photoelectron spectroscopy, surface photovoltage, and photoelectrochemical analyses indicate that buried interfaces act as electronic gates, while fast sulfide oxidation provides complementary chemical gating, together redistributing defect‐mediated recombination pathways through selective modulation of defect‐state activity. These findings demonstrate that defect‐selective recombination can be controlled to enhance photoelectrochemical performance and identify interface‐electrolyte gating as an effective strategy for solar‐driven hydrogen generation from sulfide‐containing waste streams.

Lead‐free alternatives to lead halide perovskites must achieve both high photoluminescence quantum yield (PLQY) and environmental stability for practical optoelectronic applications. While 0D copper halides demonstrate exceptional PLQY (>95%), their isolated clusters are vulnerable to moisture‐induced degradation. Conversely, 3D frameworks provide structural robustness but sacrifice luminescence efficiency. A water‐stable 3D Cu ₄ I ₄ single crystal framework (MpCuI) achieves 94% PLQY—the highest for 3D Cu ₄ I ₄ frameworks—through coordination‐driven assembly with 1‐methylpiperazine as a bifunctional N‐donor ligand. Cu─N coordination bonds (2.06–2.12 Å) extend Cu ₄ I ₄ cubane clusters into a close‐packed 3D network crystallizing in the highest‐symmetry orthorhombic space group ( Pnnn ) reported for this class. Spectroscopic and theoretical analyses reveal cluster‐centered self‐trapped exciton (CC‐STE) emission with strong exciton‐phonon coupling (Huang‐Rhys factor S = 22.54). MpCuI maintains 99.8% PLQY retention after 1‐week water immersion and demonstrates stable white‐light emission in proof‐of‐concept LED devices (CRI ∼84), establishing coordination bonding as a strategy for copper halide frameworks combining high efficiency with environmental robustness.

N-doped nanogaphene-like system decorated with 6.6.6 defects exhibits effective green TADF in neutral form. Its unique optical features allows sustaining the TADF character for bathochromically shifted emission recorded in a cationic mode.

Cyanothiazoles, small and quite overlooked molecules, possess remarkable optical properties that can be fine‐tuned through coordination with transition metals. In this study, we investigate a promising application of cyanothiazoles, where their combination with copper(I) iodide forms a new class of complexes exhibiting outstanding optical properties. X‐ray crystallography of copper(I) iodide complexes with isomeric cyanothiazoles revealed key structural features, such as π─π stacking, hydrogen bonding, and rare halogen⋅⋅⋅chalcogen I⋅⋅⋅S interactions, enhancing stability and reactivity. Advanced spectroscopy and computational modeling allowed precise identification of spectral signatures in Fourier‐transform infrared (FTIR), nuclear magnetic resonance (NMR), and ultraviolet‐visible (UV–Vis) spectra. Fluorescence studies, along with X‐ray absorption near edge structure (XANES) synchrotron analyses, highlighted their unique thermal and electronic properties, providing a solid foundation for further research in the field.

A precisely designed π-extended system responds to different stimuli by folding the structure, which prevents overoxidation and stabilizes the cation radical.

The central ion Mg²⁺ is responsible for the differences between chlorophyll a and its free base in their reactivity toward metal ions and thus their resistance to oxidation. We present here the results of spectroscopic (electronic absorption and emission, circular dichroism, and electron paramagnetic resonance), spectroelectrochemical, and computational (based on density functional theory) investigations into the mechanism of pheophytin, a degradation that occurs in the presence of Cu ions and O₂. The processes leading to the formation of the linear form of tetrapyrrole are very complex and involve the weakening of the methine bridge due to an electron withdrawal by Cu(II) and the activation of O₂, which provides protection to the free ends of the opening macrocycle. These mechanistic insights are related to the naturally occurring damage to the photosynthetic apparatus of plants growing on metal-contaminated soils.

The insertion of palladium(II) into di‐p‐pyrirubyrin results in mutually convertible bimetallic complexes. Post‐synthetic functionalization of one of them yielded bispalladium(II) dioxo‐di‐p‐pyrirubyrin and, after demetallation, dioxo‐di‐p‐pyrirubyrin, introducing for the first time the α,β′‐pyridin‐2‐one unit into the macrocyclic frame. Bispalladium(II) di‐p‐pyrirubyrin 6, bispalladium(II) dioxo‐di‐p‐pyrirubyrin 9, and dioxo‐di‐p‐pyrirubyrin 10 absorb and emit light around 1000 nm and are characterized by high photostability. Thus, they are promising candidates for near‐infrared photoacoustic dyes, ideally targeting (9) the wavelength of Yb‐based fiber lasers. The incorporation of an α,β′‐pyridine moiety into expanded porphyrins opens a highly interesting area of research due to the attractive optical and coordination properties of the resulting molecules.

The insertion of palladium(II) into di‐p‐pyrirubyrin results in mutually convertible bimetallic complexes. Post‐synthetic functionalization of one of them yielded bispalladium(II) dioxo‐di‐p‐pyrirubyrin and, after demetallation, dioxo‐di‐p‐pyrirubyrin, introducing for the first time the α,β′‐pyridin‐2‐one unit into the macrocyclic frame. Bispalladium(II) di‐p‐pyrirubyrin 6, bispalladium(II) dioxo‐di‐p‐pyrirubyrin 9, and dioxo‐di‐p‐pyrirubyrin 10 absorb and emit light around 1000 nm and are characterized by high photostability. Thus, they are promising candidates for near‐infrared photoacoustic dyes, ideally targeting (9) the wavelength of Yb‐based fiber lasers. The incorporation of an α,β′‐pyridine moiety into expanded porphyrins opens a highly interesting area of research due to the attractive optical and coordination properties of the resulting molecules.