Single‐atom catalysts (SACs) have become the forefront of energy conversion studies, but unfortunately, the origin of their activity and the interpretation of the synchrotron spectrograms of these materials remain ambiguous. Here, systematic density functional theory computations reveal that the edge sites—zigzag and armchair—are responsible for the activity of the graphene‐based Co (cobalt) SACs toward hydrogen evolution reaction (HER). Then, edge‐rich (E)‐Co single atoms (SAs) were rationally synthesized guided by theoretical results. Supervised learning techniques are applied to interpret the measured synchrotron spectrum of E‐Co SAs. The obtained local environments of Co SAs, 65.49% of Co‐4N‐plane, 13.64% in Co‐2N‐armchair, and 20.86% in Co‐2N‐zigzag, are consistent with Athena fitting. Remarkably, E‐Co SAs show even better HER electrocatalytic performance than commercial Pt/C at high current density. Using the joint effort of theoretical modeling, thorough characterization of the catalysts aided by supervised learning, and catalytic performance evaluations, this study not only uncovers the activity origin of Co SACs for HER but also lays the cornerstone for the rational design and structural analysis of nanocatalysts.

Benefiting from these unique properties, the power conversion efficiency (PCE) of perovskite solar cells (PSCs) has rapidly increased from initial ≈3% to now 25.5%, [7][8][9] situating it at the forefront of the third-generation solar cells. [10,11] Unfortunately, these ionic hybrid perovskite materials are extremely sensitive to light, [12,13] heat, [14] and moisture, [15] resulting in unstable crystal structures. During the past decade, numerous passivating methods have been developed to enhance both efficiency and long-term stability of hybrid PSCs. [16][17][18] In these polycrystalline perovskite films, defects formed at either surface or grain boundaries have been widely reported to significantly restrict carriers transport and crystal stability, which further deteriorates the device performance. [19,20] Indeed, a large number of defects are generated during the film crystallization process due to the low formation energy and soft lattice character of the perovskite crystals. [21,22] Besides, the ionic nature of hybrid halide perovskite leads to unfavorable carrier recombination and ion migration in the perovskite films, resulting in unsatisfactory efficiency or stability of the devices. [23,24] In particular, the crystallization process is accompanied by the ubiquitous formation of imperfections at grain boundaries and surfaces, metallic lead clusters, and intrinsic point defects. [24][25][26] Among them, intrinsic site Organic-inorganic hybrid lead halide perovskite solar cells have made unprecedented progress in improving photovoltaic efficiency during the past decade, while still facing critical stability challenges. Herein, the natural organic dye Indigo is explored for the first time to be an efficient molecular passivator that assists in the preparation of high-quality hybrid perovskite film with reduced defects and enhanced stability. The Indigo molecule with both carbonyl and amino groups can provide bifunctional chemical passivation for defects. In-depth theoretical and experimental studies show that the Indigo molecules firmly binds to the perovskite surfaces, enhancing the crystallization of perovskite films with improved morphology. Consequently, the Indigo-passivated perovskite film exhibits increased grain size with better uniformity, reduced grain boundaries, lowered defect density, and retarded ion migration, boosting the device efficiency up to 23.22%, and ≈21% for large-area device (1 cm 2 ). Furthermore, the Indigo passivation can enhance device stability in terms of both humidity and thermal stress. These results provide not only new insights into the multipassivation role of natural organic dyes but also a simple and low-cost strategy to prepare high-quality hybrid perovskite films for optoelectronic applications based on Indigo derivatives.

Solution processable semiconductors like organics and emerging lead halide perovskites (LHPs) are ideal candidates for photovoltaics combining high performance and flexibility with reduced manufacturing cost. Moreover, the study of hybrid semiconductors would lead to advanced structures and deep understanding that will propel this field even further. Herein, a novel device architecture involving block copolymer/perovskite hybrid bulk heterointerfaces is investigated, such a modification could enhance light absorption, create an energy level cascade, and provides a thin hydrophobic layer, thus enabling enhanced carrier generation, promoting energy transfer and preventing moisture invasion, respectively. The resulting hybrid block copolymer/perovskite solar cell exhibits a champion efficiency of 24.07% for 0.0725 cm2‐sized devices and 21.44% for 1 cm2‐sized devices, respectively, together with enhanced stability, which is among the highest reports of organic/perovskite hybrid devices. More importantly, this approach has been effectively extended to other LHPs with different chemical compositions like MAPbI3 and CsPbI3, which may shed light on the design of highly efficient block copolymer/perovskite hybrid materials and architectures that would overcome current limitations for realistic application exploration.

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Ruddlesden-Popper phase 2D perovskite solar cells (PSCs) exhibit improved lifetime while still facing challenges such as phase alignment and up-scaling to module-level devices. Herein, polyelectrolytes are explored to tackle this issue. The contact between perovskite and hole-transport layer (HTL) is important for decreasing interfacial non-radiative recombination and scalable fabrication of uniform 2D perovskite films. Through exploring compatible butylamine cations, we first demonstrate poly(3-(4-carboxybutyl)thiophene-2,5diyl)-butylamine (P3CT-BA) as an efficient HTL for 2D PSCs due to its great hydrophilicity, relatively high hole mobility and uniform surface. More importantly, the tailored P3CT-BA has an anchoring effect and acts as the buried passivator for 2D perovskites. Consequently, a best efficiency approaching 18 % was achieved and we further first report large-area (2 × 3 cm 2 , 5 × 5 cm 2 ) 2D perovskite minimodules with an impressive efficiency of 14.81 % and 11.13 %, respectively.