Xi Wang

Low-dimensional perovskite engineering offers a promising route to improve both power conversion efficiency and stability in perovskite photovoltaics, yet the mechanistic relationship between organic ligand design and structural control remains elusive. Here, we report a molecular design strategy for bis-imidazolium ligands that enables precise dimensional tuning of perovskite architectures, from zero-dimensional through parallel one-dimensional to bridged zero-dimensional configurations. Through systematic variation of terminal groups and inter-imidazole spacing, we achieve controlled growth of high-quality hybrid dimensional perovskite films with optimized crystallization kinetics and charge transport properties. This enables photovoltaic devices with a certified power conversion efficiency of 27.02% (laboratory 27.21%). Scaling this dimensional strategy enables the fabrication of 30×30 cm² perovskite solar modules, achieving a champion power conversion efficiency of 21.41% Moreover, unencapsulated devices retain 94.3% of their initial power conversion efficiency after 2000 hours of continuous operation at 60 °C (ISOS-L-2I), highlighting exceptional operational stability.

Achieving conformal, vapor-deposited perovskite films on industry-standard textured silicon substrates with micrometer-scale pyramids remains challenging because of the complex surface partitioning of perovskite vapors and the effects of nonequilibrium organic and inorganic vapor adsorption. We incorporated 3,3,3-trifluoropropyl-trimethoxysilane to enhance substrate-organic interactions, thereby optimizing surface partitioning and balancing adsorption of perovskite vapors. Vertically uniform perovskite films with minimal phase impurities formed, and nanobeam diffraction confirmed formation of the perovskite cubic phase across different pyramid regions. The resulting tandem devices achieved a power conversion efficiency of 31.3% (1 square centimeter aperture area) and exhibited excellent operational stability, retaining 90% of their initial performance after 1400 hours of continuous 1-sun illumination at 85°C.

Vacuum-assisted hybrid deposition for wide-bandgap (WBG) perovskites has been widely recognized for its advantages, including convenience for scaling up and conformal growth, while avoiding toxic solvents. However, the growth of WBG perovskites (>1.8 eV), which is critical for advancing the performance of thin-film-based tandem solar cells, remains insufficiently controlled under hybrid deposition. In this work, we introduce n-propylamine hydrochloride (PACl), which shows enhanced face-on stacking of (100) plane, effectively regulating the oriented crystal growth of 1.84 eV WBG perovskites during the annealing process. This approach reduces defect density and, consequently, improves carrier diffusion length. As a result, the hybrid-deposited WBG perovskite (>1.8 eV) solar cells realize a maximum efficiency of 17.48% and an open-circuit voltage (V_oc) exceeding 1.315 V. When integrated with organic sub-cell in a two-terminal tandem configuration, the tandem device demonstrates a record efficiency of 26.46%, with a certified efficiency of 25.82% over an active area of 0.05 cm².

The broad bandgap tunability of both perovskites and organic semiconductors enables the development of perovskite–organic tandem solar cells with promising theoretical efficiency. However, the certified efficiencies of reported perovskite–organic tandem solar cells remain lower than those of single-junction perovskite solar cells, primarily because of insufficient near-infrared photocurrent in narrow-bandgap organic subcells^1,2,3. Here we design and synthesize an asymmetric non-fullerene acceptor (NFA), P2EH-1V, featuring a unilateral conjugated π-bridge to reduce the optical bandgap to 1.27 eV while maintaining ideal exciton dissociation and nanomorphology. Transient absorption spectroscopy confirms efficient hole transfer from P2EH-1V to the donor PM6. Devices based on P2EH-1V exhibit reduced non-radiative voltage losses of 0.20 eV without compromising charge-generation efficiency. We achieve a 17.9% efficiency for the organic bottom cell, with a high short-circuit current density (J_sc) of 28.60 mA cm⁻². Furthermore, we minimize interface recombination losses, enabling the perovskite top cell to achieve an impressive open-circuit voltage (V_oc) of 1.37 V and a fill factor (FF) of 85.5%. These advancements result in perovskite–organic tandem solar cells achieving a record efficiency of 26.7% (certified at 26.4%) over an aperture area greater than 1 cm².

Employing electrochemistry for the selective functionalization of liquid alkanes allows for sustainable and efficient production of high-value chemicals. However, the large potentials required for C(sp³)-H bond functionalization and low water solubility of such alkanes make it challenging. Here we discover that a Pt/IrO_x electrocatalyst with optimized Cl binding energy enables selective generation of Cl free radicals for C-H chlorination of alkanes. For instance, we achieve monochlorination of cyclohexane with a current up to 5 A, Faradaic efficiency (FE) up to 95% and stable performance over 100 h in aqueous KCl electrolyte. We further demonstrate that our system can directly utilize concentrated seawater derived from a solar evaporation reverse osmosis process, achieving a FE of 93.8% towards chlorocyclohexane at a current of 1 A. By coupling to a photovoltaic module, we showcase solar-driven production of chlorocyclohexane using concentrated seawater in a membrane electrode assembly cell without any external bias. Our findings constitute a sustainable pathway towards renewable energy driven chemicals manufacture using abundant feedstock at industrially relevant rates.