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Photocatalysis offers a promising approach for renewable energy conversion and storage, but short lifetimes of charge-separated states in photocatalysts due to charge recombination limit its utility. Here we report an organic molecule with an acceptor-donor-acceptor configuration that can self assemble into highly crystalline nanoparticles. Transient absorption spectroscopy reveals that these crystalline assemblies can induce an ultra-long-lived charge-separated state of up to 1.2 s, attributed to initial symmetry-breaking charge separation, followed by charge hopping across closely packed molecules. These self-assembled nanoparticles have an impressive photocatalytic H2 evolution rate of 126 mmol g^-1 h^-1 with an external quantum efficiency of 12% at 550 nm under optimized conditions. This system shows a remarkable stability with 220 million turnover numbers (per particle) over the 77 h of operation. These findings suggest that rational design of organic molecules and their aggregates is vital for improving light-induced charge separation and for developing highly efficient, stable and scalable organic photocatalysts.

The integration of biological catalysts with organic light-harvesting materials represents a rapidly advancing strategy for sustainable solar-to-chemical energy conversion. Recent advances demonstrate that photoexcited organic materials can effectively activate redox enzymes and whole-cell systems to catalyze fuel-forming reactions such as H₂ evolution and CO₂ fixation as well as selective oxidations and chiral transformations under mild conditions. This review summarizes recent advances in semiartificial photosynthesis driven by organic materials and presents a systematic overview of the major classes involved. In particular, it focuses on a) organic photosensitizers including molecular organic photosensitizers, carbon dots, graphene, carbon nitride, and organic aggregation nanoparticles (e.g., polymer dots/Pdots, molecule nanoparticles) as well as b) organic redox mediators. These materials are evaluated in terms of their photophysical properties, compatibility with biocatalysts, and their roles in photoinduced charge generation, charge separation, and interfacial electron transfer between abiotic and biotic components. Emerging trends toward mediator-free and water-driven systems, challenges related to photostability, biocompatibility, as well as paired redox catalysis generating value-added products are also discussed. Additionally, the effects of the sacrificial electron donor on biohybrid performance and development of biohybrid photoelectrochemical catalysis have been evaluated. Finally, this review aims to highlight the key scientific and technological questions that must be addressed to advance the field toward efficient, scalable, and environmentally benign biohybrid photocatalytic and photoelectrochemical platforms.

The two-step sequential deposition method for perovskite solar cells (PSCs) is often limited by the dense PbI₂ film morphology, leading to incomplete conversion, residual PbI₂, and high defect density. This review consolidates research showing that engineering a porous PbI₂ architecture is a universal and transformative solution. We categorize the key strategies: (1) Solvent Engineering: Using solvent extraction, vapor treatment, or anti-solvent methods to create rapid nanoporosity; (2) Molecular Additives: Lewis bases or volatile amines that coordinate with Pb²⁺, disrupting crystallization and forming porous scaffolds; (3) Ionic Liquids and Salts: Multi-functional agents templating porosity while passivating defects and boosting stability; (4) Sacrificial Agents and Frameworks: Pore-forming compounds or MOFs/COFs that provide predefined porous structures; (5) Interfacial Engineering: Substrate modifications or low-dimensional seeds guiding favorable PbI₂ porosity. A porous PbI₂ scaffold enhances organic salt diffusion, ensuring complete conversion to high-quality perovskite films with larger grains, improved crystallinity, and lower trap densities. This consistently yields PSCs with efficiencies >25%–26% and outstanding stability, often retaining >90% performance after thousands of hours. Controlling PbI₂ morphology thus offers a scalable route to enhance perovskite photovoltaic performance and commercial viability.

We have developed two new star-shaped donor–acceptor oligomers, named TxBT and TxNT, with a truxene donor core and either 2,1,3-benzothiadiazole (BT) or a naphtho[1,2-c:5,6-c′]bis[1,2,5]thiadiazole (NT) unit, respectively. Femtosecond transient absorption spectroscopy suggested that both oligomer nanoparticles (NPs) generate long-lived triplet charge-transfer (CT) states following photoexcitation, which undergo reductive quenching by ascorbate. TxNT NPs generate a larger population of reduced species that accumulate and escape recombination compared to TxBT NPs, indicating more efficient charge separation. TxNT NPs show significantly higher hydrogen evolution rate (54 mmol h⁻¹ g⁻¹) compared to TxBT NPs, which is comparable to the performance of the most efficient heterojunction polymer NP systems. Additionally, morphological analysis revealed that Pt deposition was significantly lower on TxBT than on TxNT NPs. These findings highlight the critical role of triplet CT states, tuning molecular energy levels, optimizing excited-state dynamics, and engineering NP architecture to increase photocatalytic hydrogen evolution of organic photocatalysts. To our knowledge, this is the first report where triplet CT states can mediate photocatalytic hydrogen evolution in donor–acceptor oligomer NPs.

Spiro-OMeTAD remains the benchmark hole-transport material (HTM) in n-i-p perovskite solar cells (PSCs), playing a key role in achieving record power conversion efficiencies. However, its broad application has been critically hindered by intrinsic instability-a weakness not inherent to the spirobifluorene core, but fundamentally tied to its conventional doping system. The widespread use of hygroscopic lithium bis(trifluoromethanesulfonyl)imide (Li-TFSI) and volatile 4-tert-butylpyridine (tBP) introduces serious degradation pathways, such as Li+ migration, pinhole formation, electrode corrosion, and redox-induced de-doping. Additionally, molecular replacements for spiro-OMeTAD that require no chemical doping are highly desirable. In this review, we summarize recent advances in spiro-OMeTAD-based HTMs for PSCs, covering four main aspects: (1) synthetic routes, (2) doping mechanisms, (3) degradation processes, and (4) strategies for enhancing stability. Finally, we provide an outlook on future challenges and strategies for industrial adoption. The evolution of spiro-OMeTAD and next-generation HTMs will rely on developing "all-in-one" multifunctional formulations that integrate doping, ion immobilization, and defect passivation. Combined with scalable green synthesis, rigorous real-world stability testing, and integration with stable perovskite compositions, these approaches can transform spiro-OMeTAD from a stability concern into a versatile platform for continued innovation.

Bio-hybrid photoelectrochemical (PEC) devices integrate the complementary advantages of both biocatalyst and abiotic components, providing opportunities for efficient catalysis under mild conditions with high selectivity and low over-potential. However, the practical applications of such devices depend on the stability and efficiency of the bio-abiotic interface, where suboptimal charge transfer, biocatalyst fragility, and scalability challenges persist. In this Perspective, we evaluate established strategies for wiring biocatalysts to electrode substrates within bio-hybrid PEC architectures, analyze their catalytic performance, and operational limitations, and underly mechanistic principles. Then, we highlight the integration of whole-cell biocatalysts with high-performance semiconductor scaffolds as a promising design paradigm, offering a scalable platform for sustainable, solar-driven chemical production.

The surface chemistry of mesoporous nickel oxide (NiOx) plays a pivotal role in its functionality across various technological applications. Herein, we present a detailed study of NiOx surface states using multiple spectroscopic techniques, including ambient pressure X-ray photoelectron spectroscopy (XPS), ultraviolet-visible (UV-vis) spectroscopy, and Fourier-transform infrared (FTIR) spectroscopy, to observe the removal and reformation of surface species during gas dosing. Our findings reveal the presence of both surface oxygen- and hydroxide-species on the NiOx surface. Furthermore, the results suggest that NiO_x surface states consist of approximately 50% hydroxides and the remainder comprising adsorbed oxygen species, likely predominantly diatomic oxygen ions (O₂⁻), that are associated with higher valence Ni states (Ni³⁺). In situ experiments demonstrate that the formation and stability of hydroxides and diatomic oxygen ions depend on temperature and are significantly influenced by interactions with atmospheric oxygen and water. Our insights into the NiO_x surface state composition and reactivity offer a nuanced understanding of its surface chemistry, with implications for enhancing its performance in catalysis, sensing, energy harvesting and energy storage devices where the surface states of nickel oxide are known to dictate electronic and chemical properties of the material.

Perovskite solar cells (PSCs) have garnered significant attention in recent years due to their high performance and cost-effective fabrication processes. However, the presence of defects in the bulk and interfaces of perovskite materials can significantly impact the photovoltaic performance and stability of these devices. One approach to addressing these defects is through the use of pyridine-based organic molecules. Pyridine functional molecules have shown promise in controlling the crystallization process of perovskite films, passivating defects, and enhancing charge carrier transport. These molecules can act as solvents, passivators, and charge transport layers in PSCs, contributing to improved device efficiency and stability. In this review, the use of pyridine-based organic molecules in PSCs is summarized, highlighting their roles and applications in different aspects of device performance. The interaction mechanisms of various pyridine functional molecules with perovskite materials are discussed, shedding light on the underlying principles governing their effectiveness in enhancing device performance. The challenges and opportunities in the utilization of pyridine functional molecules in PSCs are summarized. In addition, future potential strategies for designing pyridine functional multidentate ligands are promising, emphasizing the importance of understanding the interaction mechanisms and harnessing the unique properties of pyridine-based organic molecules for improved device performance and stability.

The development of p–n tandem dye-sensitized solar cells (t-DSCs) offers the potential for substantial open-circuit voltages, holding great promise for a wide range of applications, particularly in the fields of photovoltaics and photoelectrochemical devices. Most reported t-DSCs are liquid-based, and suffer from unsatisfactory stability due to the leakage of liquid electrolytes and photovoltage that is limited to the energy difference of the two utilized semiconductors. In this study, we present the first realization of a solid-state p–n tandem dye-sensitized solar cell that incorporates both p-type and n-type solid-state dye-sensitized solar cells (ssDSCs) by using a transparent indium-doped tin oxide (ITO) back contact for both sides. Notably, this tandem system shows a remarkable open-circuit voltage of 1.4 V, surpassing the constraints of its liquid-based counterparts. Although the performance variations between p-ssDSCs and n-ssDSCs hint at challenges related to charge recombination and the efficiency of p-ssDSCs, this study underscores the significant potential inherent in solid-state tandem configurations.

Efficient photosensitizers are crucial for advancing solar energy conversion and storage technologies. In this study, we designed and synthesized a novel organic dye, denoted as YB6, for p-type dye-sensitized solar cells (p-DSCs) and photoelectrochemical H₂O₂ production. YB6 features an extended conjugated pi-bridge derived from indacenodithieno[3,2-b]thiophene and exhibits notable advantages: a two-fold higher molar extinction coefficient at its main absorption peak and a broader absorption as compared to the PB6 dye. In p-type dye-sensitized NiO photoelectrochemical cells, the YB6-based device demonstrated superior performance as compared to the PB6-based device. It delivered nearly a 50 % higher H₂O₂ production over 5 hours. Furthermore, when fabricated into p-DSCs, the YB6-based device exhibited a 33 % higher power conversion efficiency. This enhancement is caused by suppressed charge recombination from the dye structure, which in turn may be traced to a larger thermodynamic up-hill process for recombination losses in the YB6-based system.