Explore the vast range of titles available.

Two‐dimensional/three‐dimensional (2D/3D) halide perovskite heterojunctions are widely used to improve the efficiency and stability of perovskite solar cells. However, interfacial defects between the 2D and 3D perovskites and the poor coverage of the 2D capping layer still hinder long‐term stability and homogeneous charge extraction. Herein, a surface planarization strategy on 3D perovskite is developed that enables an epitaxial growth of uniform 2D/3D perovskite heterojunction via a vapor‐assisted process. The homogeneous charge extraction and suppression of interfacial nonradiative recombination is achieved by forming a uniform 2D/3D interface. As a result, a stabilized power output efficiency of 25.97% is achieved by using a 3D perovskite composition with a bandgap of 1.55 eV. To demonstrate the universality of the strategy applied for different perovskites, the champion device based on a 1.57 eV bandgap 3D perovskite results in an efficiency of 25.31% with a record fill factor of 87.6%. Additionally, perovskite solar modules achieve a designated area (24.04 cm2) certified efficiency of 20.75% with a high fill factor of 80.0%. Importantly, the encapsulated uniform 2D/3D modules retain 96.9% of the initial efficiency after 1246 h operational tracking under 65 °C (ISOS‐L‐3 protocol) and 91.1% after 862 h under the ISOS‐O‐1 protocol. By employing a surface planarization strategy, a uniform and dense p‐i‐n 2D/3D heterojunction is successfully developed. This approach has enabled planarized 2D/3D PSCs and modules to achieve remarkable efficiencies of 26.02% for a 0.1 cm2 area and 23.06% for a 22.8 cm2 area, primarily by suppressing interface nonradiative recombination. Additionally, these devices exhibit exceptional operational stability under accelerated testing protocols.

Highlights One-step in-situ incorporation of long-chain oleylammonium ligands enables simultaneous crystallographic orientation control and 2D/3D heterojunction formation in inverted perovskite solar cells. Facet engineering promotes dominant (001) orientation and higher-dimensional 2D phases (n ≥ 3) for improved energy alignment and charge extraction. Achieved power conversion efficiencies of 26.22% (0.1 cm 2 ), 24.6% (1 cm 2 ), and 21.1% (6.8 cm 2 mini-modules) with excellent photothermal and outdoor stability. Two-dimensional/three-dimensional (2D/3D) perovskite heterojunctions at the contact interfaces have been proven to enhance the stability and power conversion efficiency (PCE) of perovskite solar cells (PSCs). The 2D/3D bilayer is typically formed via a solution post-treatment onto the 3D perovskite, where the 2D layer’s dimensionality depends on the ligand size and its reactivity. Despite their stability, long-chain ligands typically form 2D perovskites with low dimensionality ( n  = 1, 2) which feature poor charge conductivity and mobility. Here, we propose an in situ fabrication method incorporating long-chain oleylammonium (OlyA + ) ligands directly into the perovskite ink. This approach forms 2D perovskite with higher dimensionalities ( n  ≥ 3) with enhanced (001) crystal facet orientation of the 3D film, improved energetic alignment, charge extraction, and structural stability. The fabricated inverted PSCs with 1.55 eV bandgap achieved a maximum PCE of 26.22% for small area and 24.6% for 1cm 2 devices, as well as 21.1% for mini-modules (6.8 cm 2 ). Additionally, the PSCs with in situ formed 2D/3D perovskite heterojunctions retained 90% and 80% of their initial PCE after 1200 h photothermal stability and 1050 h outdoor testing, respectively. Our one-step strategy produces uniform and stable 2D/3D perovskite heterojunctions with enhanced passivation capability, overcoming the limitations of conventional sequential methods and offering a promising and effective approach for highly stable and efficient PSCs.

Organic–inorganic hybrid flexible perovskite solar cells (F-PSCs) have garnered considerable interest owing to their exceptional power conversion efficiency (PCE) and stable operational characteristics. However, F-PSCs continue to exhibit significantly lower PCE than their rigid counterparts. Herein, we employed 3-chloro-4-methoxybenzylamine hydrochloride (CMBACl) treatment to grow in situ two-dimensional (2D) perovskite layers on three-dimensional (3D) perovskite films. Through comprehensive physicochemical characterization, including X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and photoluminescence (PL) mapping, we demonstrated that CMBACl treatment enabled the in situ growth of two-dimensional (2D) perovskite layers on three-dimensional (3D) perovskite films via chemical interactions between CMBA+ cations and undercoordinated Pb2+ sites. The organic cation (CMBA+) bound to uncoordinated Pb2+ ions and residual PbI2, while the chlorine anion (Cl−) filled iodine vacancies in the perovskite lattice, thereby forming a high-quality 2D/3D heterojunction structure. The CMBACl treatment effectively passivated surface defects in the perovskite films, prolonged charge carrier lifetimes, and enhanced the operational stability of the photovoltaic devices. Additionally, the hybrid 2D/3D architecture also improved energy band matching, thereby boosting charge transfer performance. The optimized flexible devices demonstrated a PCE of 23.15%, while retaining over 82% of their initial efficiency after enduring 5000 bending cycles under a 5 mm curvature radius (R = 5 mm). The unpackaged devices retained 94% of their initial efficiency after 1000 h under ambient conditions with a relative humidity (RH) of 45 ± 5%. This strategy offers practical guidelines for selecting interface passivation materials to enhance the efficiency and stability of F-PSCs.

Solar cells based on a three-dimensional (3D) crystalline perovskite framework exhibit desired photoconversion efficiency. However, 3D perovskites are prone to surface defects, leading to severe Shockley–Read–Hall (SRH) recombination and insufficient interactions between components, resulting in lower efficiency and stability. In contrast, two-dimensional (2D) perovskites have comparatively better excellent stability in hot and humid environments but suffer from lower efficiency. Recently, researchers reported that surface passivation of 3D perovskite by 2D perovskite improves the stability of solar cells without compromising their efficiency. In this review, the recent advances in surface modification of three-dimensional perovskites using two-dimensional perovskites are discussed. The crystal structures, photoelectric properties, and surface passivation strategies of 2D/3D perovskite solar cells with different components are systematically presented. Finally, the prospect of using two-dimensional perovskite passivation technology to further improve photovoltaic performance is discussed.

2D–3D mixed tin halide perovskites are outstanding candidate materials for lead‐free perovskite solar cells (PSCs) due to their improved stability and decreased trap density in comparison with their pure 3D counterparts. However, the mixture of multiple phases may lead to poor charge transfer across the films and limit the device efficiency. Here, a stacked quasi‐2D (down)–3D (top) double‐layered structure in perovskite films prepared via vacuum treatment is demonstrated, which can result in a planar bilayer heterojunction. In addition, it is found that the introduction of guanidinium thiocyanate (GuaSCN) additive can improve the crystallinity and carrier mobility in the 2D perovskite layer and passivate defects in the whole film, leading to a long carrier lifetime (>140 ns) in photoluminescence measurements. As a result, the PSCs show a high open circuit voltage (VOC) up to 1.01 V with a voltage loss of only 0.39 V, which represents the record values ever reported for tin‐based PSCs. The champion device exhibits a power conversion efficiency (PCE) of 13.79% with decent stability, retaining 90% of the initial PCE for 1200 h storage in N2‐filled glovebox. The type‐II 2D/3D vertical heterojunction is created in tin‐based perovskite films, which is favorable for charge transfer. Moreover, guanidinium thiocyanate additive is introduced to construct conducting channels for hole transfer in the 2D layer and reduce recombination loss in the whole films. The resultant solar cells show a record open circuit voltage of 1.01 V.

Highlights Two triphenylamine-based semiconducting ligands, namely N-TPEAI and P-TPEAI, were designed by extending the π-conjugation, with structural similarities to the backbone of poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine] (PTAA). This π -conjugation extension strategy proves to be effective in strengthening intermolecular interactions both between adjacent spacer cations within 2D perovskites and at perovskite/PTAA interfaces. The resultant 2D/3D perovskite solar cells (PSCs) employing P-TPEAI achieve an outstanding efficiency of 26.13%, which is the highest value reported for 2D/3D PSCs incorporating PTAA hole-transport layers. Constructing 2D/3D perovskite heterojunction is an effective method to improve performance and stability of perovskite solar cells (PSCs), while the quantum well in 2D perovskites hinders carrier transport. To address this issue, π -conjugated semiconducting ligands have been introduced to enhance carrier-transfer capability of 2D perovskites. Here, two triphenylamine (TPA)-based ligands are specifically designed through π -extension with a fused (N-TPEAI) or covalently linked (P-TPEAI) benzene ring. For the first time, TPA semiconductor-based ligands have been incorporated to construct 2D/3D PSCs with poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine] (PTAA) as hole-transport materials (HTMs). Combined experimental and computational analyses reveal that this π -conjugation extension strategy proves to be effective in strengthening intermolecular interactions both between the adjacent spacer cations within 2D perovskites and at perovskite/PTAA interfaces, particularly in the case of P-TPEAI. Ultimately, the resultant 2D/3D PSCs employing P-TPEAI achieve an outstanding efficiency of 26.13%, which, to the best of our knowledge, is the highest value reported for 2D/3D PSCs incorporating PTAA HTMs. Moreover, benefiting from the robustness of both 2D perovskites and PTAA, the corresponding devices also exhibit excellent light-heat stability, meeting ISOS-L-2 protocol. These findings provide important guidelines for future design of organic spacers in advancing efficient and robust PSCs and related optoelectronic devices.

Two-dimensional/three-dimensional (2D/3D) hierarchical structure has attracted extensively attention in recent years due to their stability and the enhanced open-circuit voltage of perovskite solar cells. However, the solution processed thin 2D perovskite layers on the surface of 3D perovskites would lead to undesirable intermixing between the two phases, impeded carrier transport. Here, we present a novel approach for fabricating 2D perovskite on 3D perovskite using vapor-assisted solution deposition. Unlike what is normally observed in solution-processed 3D/2D systems, a flat interface formed in the 2D/3D bilayer heterostructure. The vapor-deposited 2D perovskite capping layer promotes efficient electron and hole separation processes and significantly restrain non-radiative charge recombination. This innovative stable and low-cost architecture will enable the timely commercialization of perovskite solar cells.

The noteworthy stability of Dion–Jacobson (DJ) phase two-dimensional perovskites marks them as potential contenders for use in optoelectronic applications. Nonetheless, their proliferation is considerably stymied by the constrained charge transport properties inherent to them. This bottleneck is adeptly navigated by deploying 2D-DJ perovskite top layers, seamlessly integrated on 3D perovskite films. We unveil a novel organic cation salt, 4-(Aminomethyl)piperidine (4AMP), as a potent facilitator for treating perovskite photovoltaic films. By employing the annealing technique, we facilitated the in situ creation of a hybrid 2D/3D architecture. Contrasted with conventional 3D architectures, the delineated perovskite heterojunctions with a 2D/3D structure exhibit superior enhanced charge separation, and mitigate photovoltaic losses by proficiently passivating intrinsic defects. The size-graded perovskite 2D/3D structure engineered herein significantly elevates the charge transfer performance, concurrently attenuating the excess lead iodide induced by bulk defects. This precise method resulted in a significant increase in Power Conversion Efficiency, reaching 23.08%, along with an open-circuit voltage (Voc) of 1.17 V. Remarkably, the unpackaged modified device robustly retains 92% of its initial PCE post a 3000 h sojourn under ambient conditions. This discourse propounds a novel paradigm for constructing stable planar PSC 2D/3D heterojunctions, thereby enriching the blueprint for advanced perovskite-based photovoltaic systems.