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Due to the higher photon energy under indoor photovoltaic conditions, using perovskite materials with wider bandgaps has become a consensus. However, updating perovskite absorbers requires additional adaptations involving at least two layers of transport materials and two interfaces, increasing the development complexity. This study acknowledges that the buried interface is the primary location for the generation of photoinduced carriers, and achieving efficient carrier separation and transport at this interface will solve most of the open circuit voltage (VOC) loss issues encountered in transitioning from solar photovoltaics to indoor photovoltaics. Therefore, a class of bipolar pseudohalide ammonium salts is proposed for use as bridging agents for the buried interface to effectively resolve the issues of lattice misalignment and insufficient carrier driving force at the buried interface when broadening the perovskite bandgap, thereby reducing VOC loss in indoor photovoltaics. The optimized device exhibits an excellent photoelectric conversion efficiency (PCE) of 41.04%, with a record‐high VOC of 1.08 V. It also demonstrates impressive long‐term operational stability with a T80 lifetime of 1000 h. Substituting various non‐buried interface transport materials and different categories of wide‐bandgap perovskite absorbers does not alter the effectiveness, proving its universality. [ABSTRACT FROM AUTHOR]

The quality of the buried interface plays a key role in achieving high‐performance perovskite solar cells (PSCs). However, it is challenging to guarantee its quality on a larger area, which is pivotal for the commercialization of PSCs. Here, a facile strategy is developed to modify the SnO2/perovskite buried interface by incorporating L‐Aspartic acid monosodium salt (ASP‐Na) into SnO2 colloidal dispersion. ASP‐Na with multidentate ligands can coordinate with Sn to form stable dispersion, inhibiting the agglomeration of nanoparticles at the buried interface. In addition, the coordination between ASP‐Na and SnO2 nanoparticles in turn promotes the uniform distribution of ASP‐Na, which facilitates the uniform and effective passivation of the buried defects. Consequently, the ASP‐Na treatment improves the device efficiency from 23.44% to 25.47% (certified 25.02%) with an aperture area of 0.0797 cm2 without hysteresis and enhances the operation stability. The perovskite mini‐module achieves an efficiency of 20.11% with an aperture area of 18.30 cm2, demonstrating the potential of the strategy for scalability. [ABSTRACT FROM AUTHOR]

Perovskite solar cells (PSCs) are considered the most promising photovoltaic devices to replace silicon-based solar cells because of their low preparation cost and high photoelectric conversion efficiency (PCE). Reducing defects in perovskite films is an effective means to improve the efficiency of PSCs. In this paper, a lead chelator was selected and mixed into hole transport layers (HTLs) to design and prepare mesoporous PSCs with the structure of ITO/PTAA(BCP)/Al2O3/PVK/PCBM/BCP/Ag, and its modification effect on the buried interface at the bottom of the perovskite layer in the mesoporous structure was explored. The experimental results show that in the presence of mesoporous alumina, the lead chelator can still play a role in modifying the bottom of the perovskite film. The use of lead chelator as passivation material added to the HTL can effectively reduce the residue of dimethyl sulfoxide (DMSO) and decrease the defects at the bottom of the perovskite film, which dramatically improves the device performance. The PCE of the device is increased from 18.03% to 20.78%, which is an increase of 15%. The work in this paper provides an effective method to enhance the performance of PSCs. [ABSTRACT FROM AUTHOR]

Scalable deposition of high-efficiency perovskite solar cells (PSCs) is critical to accelerating their commercial applications. However, a significant number of defects are distributed at the buried interface of perovskite film fabricated by scalable deposition, exhibiting much negative influence on the efficiency and stability of PSCs. Herein, 2-(N-morpholino)ethanesulfonic acid potassium salt (MESK) is incorporated as the bridging layer between the tin oxide (SnO2) electron transport layer (ETL) and the perovskite film deposited via scalable two-step doctor blading. Both experiment and simulation results demonstrate that MESK can passivate the trap states of Sn suspension bonds, thereby enhancing the charge extraction and transport of the SnO2 ETL. Meanwhile, the strong interaction with uncoordinated Pb ions can modulate the crystal growth and crystallographic orientation of perovskite film and passivate buried defects. With employing MESK interface bridging, PSCs fabricated via scalable doctor blading in ambient condition achieve a power conversion efficiency (PCE) of 24.67%, which is one of the highest PCEs for doctor-bladed PSCs, and PSC modules with an active area of 11.35 cm2 achieve a PCE of 19.45%. Furthermore, PSCs exhibit excellent long-term stability, and the unpackaged target device with a storage of 1680 h in ambient condition (25 °C and humidity of 30% relative humidity (RH)) can maintain more than 90% of the initial PCE. The research provides a strategy for constructing a high-performance interface bridge between SnO2 ETL and perovskite film, and achieving efficient and stable large-area PSCs and modules fabricated via scalable doctor-blading process in ambient condition. [ABSTRACT FROM AUTHOR]

Mixed‐halide perovskites are emerging as excellent photovoltaic candidates because of their tunable bandgaps for semitransparent and tandem perovskite solar cells. However, the notorious film quality originated from the rapidly downward crystallization process susceptibly propagates enormous detrimental defects, which deteriorate the photovoltaic performance and accelerate halide segregation. To address this issue, herein, a multilayer alkalis‐intercalated‐vermiculite is employed as pre‐buried interface modifier to regulate the perovskite lattice property. The matchable lattice structure between perovskite and vermiculite by forming Pb─O bond not only releases the interfacial strain during the film growth but also the embedded alkalis ions can gradually diffuse into perovskite lattice to form a favorable vertical gradient owing to the weak interlamellar van der Waals interaction, playing bis‐roles of atomical lubricant and ion‐reservoir to eliminate detrimental defects. As a result, the film quality and lattice stability is significantly improved with suppressed phase segregation for mixed‐halide perovskites, accompanying a champion efficiency of 11.42% for carbon‐based CsPbIBr2 device, 15.25% for carbon‐based CsPbI2Br device and 23.17% for p‐i‐n inverted (Cs0.05MA0.05FA0.9)Pb(I0.93Br0.07)3 cell. This work provides a new strategy on buried interface engineering for making high‐efficiency and stable perovskite platforms. [ABSTRACT FROM AUTHOR]

The rationale for low performances in perovskite solar cells with buried interface still needs to be clarified, owing to the complicated physiochemistry of metal oxides/perovskite interface, and literature offers a meager knowledge about the reactions at this interface. While exploring the SnO2/perovskite interfacial interactions, the reasons behind deteriorating perovskite at the interface are comprehensively investigated, and it is revealed that the PbI2 residue and metallic Pb0 are the byproducts of this decomposed perovskite. Introducing an optimized amount of Ti3C2TX at the SnO2/perovskite interface detaches the SnO2 hydroxyls, which are found to be responsible for interfacial ion migrations. In addition, Ti3C2TX passivates the interface defects via its functional groups and establishes ballistic pathways for electrons with high chances of non‐radiative recombination. Thus, 25.19% (certified as 24.41%) of efficiency with superior long‐term operational stability is achieved. [ABSTRACT FROM AUTHOR]

The rationale for low performances in perovskite solar cells with buried interface still needs to be clarified, owing to the complicated physiochemistry of metal oxides/perovskite interface, and literature offers a meager knowledge about the reactions at this interface. While exploring the SnO2/perovskite interfacial interactions, the reasons behind deteriorating perovskite at the interface are comprehensively investigated, and it is revealed that the PbI2 residue and metallic Pb0 are the byproducts of this decomposed perovskite. Introducing an optimized amount of Ti3C2TX at the SnO2/perovskite interface detaches the SnO2 hydroxyls, which are found to be responsible for interfacial ion migrations. In addition, Ti3C2TX passivates the interface defects via its functional groups and establishes ballistic pathways for electrons with high chances of non‐radiative recombination. Thus, 25.19% (certified as 24.41%) of efficiency with superior long‐term operational stability is achieved. [ABSTRACT FROM AUTHOR]

Harmonizing homogeneity in charge distribution within metal halide perovskite solar cells is essential for maintaining device quality. The adsorption of ions from perovskites onto the electron transport layer leads to the creation of redistributed space‐charge regions (SCR), which facilitate halide segregation and ionic migration, resulting in charge imbalances and diminished extraction capability at the interface. The research examines the intricate interplay between SCRs affecting iodide oxidation and their impact on photovoltaics, uncovering a previously overlooked aspect that the influence of ionic accumulation on electronic charge uniformity. A paradox is identified that electronic charge accumulation at interfaces improves initial open‐circuit voltage, however, compromises stability with a collapsed charge distribution. To address this issue, ion conduction is regulated by utilizing a self‐assembled 2D perovskite resulting from cationic exchange with a low migration barrier at the buried interface, thereby mitigating halide segregation and charge inhomogeneity. This approach exhibits a power conversion efficiency (PCE) of 24.38% with a fill‐factor of 84% and maintains 91.87% of the initial PCE for a duration of 2070 h. [ABSTRACT FROM AUTHOR]

Highlights Developing a universal strategy of the p–n homojunction engineering that could significantly boost electron mobility of electron transport layer (ETL) by two orders of magnitude. Proposing a new mechanism based on p–n homojunction to explain inhibited carrier loss at buried interface. Setting a new performance benchmark as high as 25.50% for planar perovskite solar cells employing TiO2 as ETLs.

The power conversion efficiency (PCE) of perovskite solar cells (PSCs) is approaching their Shockley‐Queisser (S‐Q) limit through numerous efforts in key parameters improvement. To further approaching the limit, it is important to facilitate the fill factor (FF), a parameter closely related to carrier transport and nonradiative recombination. Herein, an interfacial bridging strategy is proposed to improve FF, which utilizes functional graphene quantum dots at the tin oxide (SnO2)/perovskite buried interface. As a result, synergistic effects of enhanced conductivity of SnO2, preferable energy alignment at the buried interface and improved perovskite crystal orientation are realized. The champion FF reaches 85.24% in formamidinium lead iodide (FAPbI3) based PSCs, which ranks among the highest in the n‐i‐p structure. Such strategy is also proven successful in other perovskite systems, where the champion PCE reaches 24.86% in the formamidinium‐cesium (FACs)‐based devices and 24.44% in the flexible devices. Therefore, this work provides a practical design rule for pursuing high FF of PSCs with carbon materials. [ABSTRACT FROM AUTHOR]

[Display omitted] Perovskite light-emitting diodes (PeLEDs) exhibit remarkable potential in the field of displays and solid-state lighting. However, blue PeLEDs, a key element for practical applications, still lag behind their green and red counterparts, due to a combination of strong nonradiative recombination losses and unoptimized device structures. In this report, we propose a buried interface modification strategy to address these challenges by focusing on the bottom-hole transport layer (HTL) of the PeLEDs. On the one hand, a multifunctional molecule, aminoacetic acid hydrochloride (AACl), is introduced to modify the HTL/perovskite interface to regulate the perovskite crystallization. Experimental investigations and theoretical calculations demonstrate that AACl can effectively reduce the nonradiative recombination losses in bulk perovskites by suppressing the growth of low- n perovskite phases and also the losses at the bottom interface by passivating interfacial defects. On the other hand, a self-assembly nanomesh structure is ingeniously developed within the HTLs. This nanomesh structure is meticulously crafted through the blending of poly-(9,9-dioctyl-fluorene-co-N-(4-butyl phenyl) diphenylamine) and poly (n-vinyl carbazole), significantly enhancing the light outcoupling efficiency in PeLEDs. As a result, our blue PeLEDs achieve remarkable external quantum efficiencies, 20.4% at 487 nm and 12.5% at 470 nm, which are among the highest reported values. Our results offer valuable insights and effective methods for achieving high-performance blue PeLEDs. [ABSTRACT FROM AUTHOR]

Perovskite solar cells (PSC) have developed rapidly since the past decade with the aim to produce highly efficient photovoltaic technology at a low cost. Recently, physical and chemical defects at the buried interface of PSC including vacancies, impurities, lattice strain, and voids are identified as the next formidable hurdle to the further advancement of the performance of devices. The presence of these defects has unfavorably impacted many optoelectronic properties in the PSC, such as band alignment, charge extraction/recombination dynamics, ion migration behavior, and hydrophobicity. Herein, a broad but critical discussion on various essential aspects related to defects at the buried interface is provided. In particular, the defects existing at the surface of the underlying charge transporting layer (CTL) and the bottom surface of the perovskite film are initially elaborated. In situ and ex situ characterization approaches adopted to unveil hidden defects are elucidated to determine their influence on the efficiency, operational stability, and photocurrent–voltage hysteresis of PSC. A myriad of innovative strategies including defect management in CTL, the introduction of passivation materials, strain engineering, and morphological control used to address defects are also systematically elucidated to catalyze the further development of more efficient, reliable, and commercially viable photovoltaic devices. [ABSTRACT FROM AUTHOR]

The self‐assembled monolayer (SAM) is now widely applied at the hole‐selective interface of efficient inverted perovskite solar cells (PSCs). However, voids are unavoidable in SAMs due to the rough substrate and the deposition conditions, which lead to direct contact between the active layer and electrode, undermining the efficiency and stability of PSCs. Here, alkylphosphonic acids with different alkyl chain length are post‐assembled to fill the voids, thereby forming a compact po‐SAM layer. By further modifying the head group of alkylphosphonic acids, the efficiency and stability of PSCs are improved due to wetting and passivation. Finally, the po‐SAM layer formed by (2‐Bromoethyl) phosphonic acid and [4‐(3,6‐dimethyl‐9H‐carbazol‐9‐yl)butyl] phosphonic acid contributes to a champion device with the power conversion efficiency of 25.16% (certified 24.67%) and improved stability under operation or storage. This work demonstrates the advantages of po‐SAM layer in improving the performance of PSCs, offering ideas for SAM modification. [ABSTRACT FROM AUTHOR]

In the rapidly advancing realm of perovskite solar cells, the rectification of defects has surfaced as a crucial scientific challenge. The control over defect states, especially in printable mesoscopic perovskite solar cells (p‐MPSCs), is hindered by the complexities of screen‐printing technology. Here a novel “two‐in‐one” defect passivation strategy is presented, through doping TiO2 paste with cesium halide salts (CsX, where X = F, Cl, Br, I) to integrate all‐inorganic Cs halides, particularly CsF, into the electron transport layer in p‐MPSCs. Owing to the robust interaction between F− ions and TiO2 compared to Cs+ ions, and the inability of F− to infiltrate the perovskite lattice, F− and Cs+ play distinct roles starting from the buried interface of the p‐MPSCs. Specifically, F− can rectify the oxygen vacancies on the TiO2 surface, thus alleviating the residual stress at the perovskite's buried interface. Simultaneously, Cs+ diffuses to the top perovskite and mends the methylamine vacancies. As a result, the PCE of the optimal device, based on F‐doped TiO2, witnesses a significant improvement from 16.18% (control) to 18.24%. The two‐in‐one strategy utilizing CsX from the buried interface can well realize the all‐inorganic defect rectification, thereby offering a promising prospect for the enhancement of p‐MPSC performance. [ABSTRACT FROM AUTHOR]

Light-induced phase segregation, particularly when incorporating bromine to widen the bandgap, presents significant challenges to the stability and commercialization of perovskite solar cells. This study explores the influence of hole transport layers, specifically poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine (PTAA) and [4-(3,6-dimethyl-9H-carbazol-9-yl)butyl]phosphonic acid (Me-4PACz), on the dynamics of phase segregation. Through detailed characterization of the buried interface, we demonstrate that Me-4PACz enhances perovskite photostability, surpassing the performance of PTAA. Nanoscale analyses using in situ Kelvin probe force microscopy and quantitative nanomechanical mapping techniques elucidate defect distribution at the buried interface during phase segregation, highlighting the critical role of substrate wettability in perovskite growth and interface integrity. The integration of these characterization techniques provides a thorough understanding of the impact of the buried bottom interface on perovskite growth and phase segregation. [ABSTRACT FROM AUTHOR]

All‐perovskite tandem solar cells (ATSCs) present a remarkable opportunity to overcome the Shockley–Queisser efficiency limit of single‐junction solar cells. However, the stability of ATSCs significantly lags that of their pure Pb‐based single‐junction counterparts. Recent studies have identified that the widely used poly(3,4‐ethylenedioxythiophene)‐poly(styrenesulfonate) (PEDOT:PSS) hole transport layer in narrow‐bandgap (NBG) tin–lead (Sn–Pb) perovskite solar cells (PSCs) hinders the efficiency and stability. Herein, a patching strategy to optimize the interface between perovskite and PEDOT:PSS is proposed. Both theoretical and experimental studies reveal that PenA+ and Ac− can decrease defect states at the interface and strengthen the binding between PEDOT:PSS and Sn–Pb perovskite. Furthermore, the pentylammonium acetate (PenAAc) interlayer improves carrier extraction and suppresses the oxidation of Sn2+ to Sn4+. With the PenAAc buried layer, the fabricated NBG PSCs obtain an impressive power conversion efficiency (PCE) of 21.86%, along with significantly enhanced device stability. By integrating the buried passivated NBG Sn–Pb perovskite with a 1.75 eV wide‐bandgap PSC, the two‐terminal ATSC achieves a PCE of 26.54%. This work provides a valuable approach to fabricate efficient and stable NBG PSCs. [ABSTRACT FROM AUTHOR]

Interface engineering is known for effectively improving interfacial contact and passivating defects to enhance device performance of inverted perovskite solar cells (PSCs). Currently, most of works focus on surface passivation, while the buried interface is equally important. The film quality of perovskite layer greatly relies on the buried interface, leaving a pronounced impact on overall device performance. In addition, resolving defects and energy level mismatch at buried interface remains challenging. Optimizing the buried interface becomes a promising approach for high‐efficiency inverted PSCs. This review summarizes recent advances in buried interface engineering and emphasize the importance of corresponding characterization techniques. The various functions of buried interface engineering are carefully discussed, including crystallization modulation, defect passivation, energy level alignment, chemical reaction inhibition, chemical bridge, dipole cancellation and novel buried interfacial techniques. Finally, current challenges and prospects are put forward that should be addressed to further improve device performance of inverted PSCs. [ABSTRACT FROM AUTHOR]

Well‐engineered buried interfaces play a pivotal role in achieving high‐performance perovskite solar cells (PSCs). A superior buried interface involves controlled perovskite crystallization, efficient charge transfer across interfaces, and robust interfacial bonding. Here, a class of innovative additives, benzoyl sulfonyl molecules including 4‐sulfobenzoic acid monopotassium salt (K‐SBA), and 4‐sulfamoylbenzoic acid (SBA) is introduced to tailer the SnO2/perovskite buried interface, aiming to meet these essential criteria. Among them, K‐SBA performed better. The findings reveal that the functional groups of K‐SBA establish interactions with both SnO2 and perovskite, leading to effective bilateral passivation and mitigation of interface stress. This results in the formation of a pore‐free buried interface and high‐quality perovskite films with substantial crystal sizes. Consequently, PSCs incorporating K‐SBA exhibited a notable increase in efficiency, achieving 24.56% efficiency compared to the control device's 22.27%. Furthermore, these K‐SBA‐enhanced PSCs maintain 90% of their original efficiency even after 500 h of maximum power point tracking. This work provides valuable insights for further refinement and advancement of buried interfaces in PSCs. [ABSTRACT FROM AUTHOR]

Interfacial modification is a key strategy for improving the performance of perovskite photovoltaic devices. While the modification of the top surface of the perovskite active layer is well established, engineering of the buried interface is highly challenging. Here, the spontaneous formation of a 1D/3D perovskite heterojunction at the buried interface of a perovskite active layer by incorporating choline acetate alongside the perovskite precursors is reported. Importantly, extensive spectroscopic and microscopic characterization and solid‐state nuclear magnetic resonance experiments demonstrate the formation of phase‐pure 1D and 3D domains. The 1D/3D junction results in a suppression of the defect states and an improved energetic level alignment at the buried interface, leading to a maximum power conversion efficiency of >24% when incorporated in inverted architecture perovskite solar cells. This work introduces a versatile approach to the modification of the buried interface of the perovskite active layer. [ABSTRACT FROM AUTHOR]

In a methylammonium‐free (MA‐free) composition, the uncontrollable crystallization process between Cs and formamidine (FA) currently hinders its efficiency enhancement, especially in inverted perovskite solar cells (PSCs). Here, a dual‐interface modification of perovskite films is proposed by simultaneously introducing additives and surface passivators. In particular, (aminomethyl)phosphonic acid (AMP) is introduced into the precursor solution to balance crystallization by inducing the preferential crystallization of FA through the specific formation of strong hydrogen bonds with FA. In addition, AMP spontaneously sinks and anchors to the buried interface to fill the voids of the self‐assembled monolayer (SAM) via the covalent bonds formed by ─PO3H2 and FTO. Subsequently, by the sequential modification of perovskite surface with 2‐(3‐fluorophenyl)ethylamine iodide (mF‐PEAI) and piperazine diiodide (PDI), a uniform surface potential is achieved and recombination losses at the interface are minimized. Notably, the dual‐interface‐modified inverted MA‐free PSCs achieve a state‐of‐the‐art power conversion efficiency (PCE) of 25.35% (certified: 24.87%) with a satisfactory Voc of 1.17 V based on the bandgap of 1.52 eV. Importantly, the unencapsulated devices maintain 92.8% and 91.7% of the initial efficiency after 1000 h of maximum power output (MPP) tracking and >800 h of heating at 85 °C, respectively, confirming excellent operational and thermal stability. [ABSTRACT FROM AUTHOR]

Highlights: Developing a universal strategy of the p–n homojunction engineering that could significantly boost electron mobility of electron transport layer (ETL) by two orders of magnitude. Proposing a new mechanism based on p–n homojunction to explain inhibited carrier loss at buried interface. Setting a new performance benchmark as high as 25.50% for planar perovskite solar cells employing TiO2 as ETLs. Low-temperature processed electron transport layer (ETL) of TiO2 that is widely used in planar perovskite solar cells (PSCs) has inherent low carrier mobility, resulting in insufficient photogenerated electron transport and thus recombination loss at buried interface. Herein, we demonstrate an effective strategy of laser embedding of p-n homojunctions in the TiO2 ETL to accelerate electron transport in PSCs, through localized build-in electric fields that enables boosted electron mobility by two orders of magnitude. Such embedding is found significantly helpful for not only the enhanced crystallization quality of TiO2 ETL, but the fabrication of perovskite films with larger-grain and the less-trap-states. The embedded p–n homojunction enables also the modulation of interfacial energy level between perovskite layers and ETLs, favoring for the reduced voltage deficit of PSCs. Benefiting from these merits, the formamidinium lead iodide (FAPbI3) PSCs employing such ETLs deliver a champion efficiency of 25.50%, along with much-improved device stability under harsh conditions, i.e., maintain over 95% of their initial efficiency after operation at maximum power point under continuous heat and illumination for 500 h, as well as mixed-cation PSCs with a champion efficiency of 22.02% and over 3000 h of ambient storage under humidity stability of 40%. Present study offers new possibilities of regulating charge transport layers via p-n homojunction embedding for high performance optoelectronics. [ABSTRACT FROM AUTHOR]

Targeting the trap‐assisted non‐radiative recombination losses and photochemical degradation occurring at the interface and bulk of perovskite, especially the overlooked buried bottom interface, a strategy of tailored‐phase two‐dimensional (TP‐2D) crystal seed layer has been developed to improve the charge transport dynamics at the buried interface and bulk of perovskite films. Using this approach, TP‐2D layer constructed by TP‐2D crystal seeds at the buried interface can induce the formation of homogeneous interface electric field, which effectively suppress the accumulation of charge carriers at the buried interface. Additionally, the presence of TP‐2D crystal seed has a positive effect on the crystallization process of the upper perovskite film, leading to optimized crystal quality and thus promoted charge transport inside bulk perovskites. Ultimately, the best performing PSCs based on TP‐2D layer deliver a power conversion efficiency of 24.58 %. The devices exhibit an improved photostability with 88.4 % of their initial PCEs being retained after aging under continuous 0.8‐sun illumination for 2000 h in air. Our findings reveal how to regulate the charge transport dynamics of perovskite bulk and interface by introducing homogeneous components. [ABSTRACT FROM AUTHOR]

In perovskite solar cells (PSCs), the buried interface between the electron transfer layer (ETL) and perovskite (PVK) layer profoundly affects the charge carrier transfer efficiency, which has significant implications for the efficiency and long‐term stability of the device. Herein, an organic chemical compound 4,6‐diamino‐2‐mercaptosine (DMP) is incorporated into the ETL/PVK interface in order to optimize the interfacial performance through a hydrogen bond bridging junction. DMP is tightly anchored to the ETL surface by forming the intermolecular hydrogen bonding with the structure as N─H∙∙∙N. This bridge connection is beneficial for enhancing the interface contact, further restraining severe nonradiative charge recombination. Synchronously, the interaction of ─SH with uncoordinated Pb2+ passivates the defects on the bottom layer of perovskite, further regulating the perovskite crystal growth. Overall, the results express that the power conversion efficiency (PCE) of PSCs based on the DMP interface has significantly increased to 21.65% without obvious hysteresis. Meanwhile, the unencapsulated modified devices show superior environmental stability, maintaining over 85% of their initial PCE even after 500 h in an atmospheric environment. [ABSTRACT FROM AUTHOR]

The phase segregation of wide-bandgap perovskite is detrimental to a device's performance. We find that Sodium Benzenesulfonate (SBS) can improve the interface passivation of PTAA, thus addressing the poor wettability issue of poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine](PTAA). This improvement helps mitigate interface defects caused by poor contact between the perovskite and PTAA, reducing non-radiative recombination. Additionally, enhanced interface contact improves the crystallinity of the perovskite, leading to higher-quality perovskite films. By synergistically controlling the crystallization and trap passivation to reduce the phase segregation, SBS-modified perovskite solar cells (PSCs) achieved a power conversion efficiency (PCE) of 20.27%, with an open-circuit voltage (Voc) of 1.18 V, short-circuit current density (Jsc) of 20.93 mA cm−2, and fill factor (FF) of 82.31%. [ABSTRACT FROM AUTHOR]

The efficiency loss caused by area scaling is one of the key factors hindering the industrial development of perovskite solar cells. The energy loss and contact issues in the buried interface are the main reasons. Here, a new self‐assembled monolayer (SAM), Ph‐4PACz, with a large dipole moment (2.32 D) is obtained. It is found that Ph‐4PACz with high polarity can improve the band alignment and minimize the energy loss , resulting in an open‐circuit voltage (Voc) as high as 1.2 V for 1.55 eV perovskite. However, when applied to large‐area devices, the fill factor (FF) still suffered from significant attenuation. Therefore, alumina nanoparticles (Al2O3‐NPs) are introduced to the interface between Ph‐4PACz and rough FTO substrate to further improve the flatness , resulting in a conformal perovskite film with almost no voids in the buried interface, thus promoting low exciton binding energy, fast hot‐carrier extraction and low non‐radiative recombination. The final devices achieved a small‐area power conversion efficiency (PCE) of 25.60% and a large‐area (1 cm2) PCE of 24.61% (certified at 24.48%), which represents one of the highest PCE for single device ≥ 1 cm2 area. Additionally, mini‐modules and stability testing are also carried out to demonstrate the feasibility of commercialization. [ABSTRACT FROM AUTHOR]

The instability of the buried interface poses a serious challenge for commercializing perovskite photovoltaic technology. Herein, we report a polydentate ligand reinforced chelating strategy to strengthen the stability of buried interface by managing interfacial defects and stress. The bis(2,2,2‐trifluoroethyl) (methoxycarbonylmethyl)phosphonate (BTP) is employed to manipulate the buried interface. The C=O, P=O and two −CF3 functional groups in BTP synergistically passivate the defects from the surface of SnO2 and the bottom surface of the perovskite layer. Moreover, The BTP modification contributes to mitigated interfacial residual tensile stress, promoted perovskite crystallization, and reduced interfacial energy barrier. The multidentate ligand modulation strategy is appropriate for different perovskite compositions. Due to much reduced nonradiative recombination and heightened interface contact, the device with BTP yields a promising power conversion efficiency (PCE) of 24.63 %, which is one of the highest efficiencies ever reported for devices fabricated in the air environment. The unencapsulated BTP‐modified devices degrade to 98.6 % and 84.2 % of their initial PCE values after over 3000 h of aging in the ambient environment and after 1728 h of thermal stress, respectively. This work provides insights into strengthening the stability of the buried interface by engineering multidentate chelating ligand molecules. [ABSTRACT FROM AUTHOR]

Buried interface modification can effectively improve the compatibility between interfaces. Given the distinct interface selections in perovskite solar cells (PSCs), the applicability of a singular modification material remains limited. Consequently, in response to this challenge, we devised a tailored molecular strategy based on the electronic effects of specific functional groups. Therefore, we prepared three distinct silane coupling agents, and due to the varying inductive effects of these functional groups, the electronic distribution and molecular dipole moments of the coupling agents are correspondingly altered. Among them, trimethoxy (3,3,3‐trifluoropropyl)‐silane (F3‐TMOS), which possesses electron‐withdrawing groups, generates a molecular dipole moment directed toward the hole transport layer (HTL). This approach changes the work function of the HTL, optimizes the energy level alignment, reduces the open‐circuit voltage loss, and facilitates carrier transport. Furthermore, through the buffering effect of the coupling agent, the interface strain and lattice distortion caused by annealing the perovskite are reduced, enhancing the stability of the tin‐based perovskite. Encouragingly, tin PSCs treated with F3‐TMOS achieved a champion efficiency of 14.67 %. This strategy provides an expedient avenue for the design of buried interface modification materials, enabling precise molecular adjustments in accordance with distinct interfacial contexts to ameliorate mismatched energetics and enhance carrier dynamics. [ABSTRACT FROM AUTHOR]

Perovskite solar cells (PSCs) are considered the most promising photovoltaic devices to replace silicon-based solar cells because of their low preparation cost and high photoelectric conversion efficiency (PCE). Reducing defects in perovskite films is an effective means to improve the efficiency of PSCs. In this paper, a lead chelator was selected and mixed into hole transport layers (HTLs) to design and prepare mesoporous PSCs with the structure of ITO/PTAA(BCP)/Al2O3/PVK/PCBM/BCP/Ag, and its modification effect on the buried interface at the bottom of the perovskite layer in the mesoporous structure was explored. The experimental results show that in the presence of mesoporous alumina, the lead chelator can still play a role in modifying the bottom of the perovskite film. The use of lead chelator as passivation material added to the HTL can effectively reduce the residue of dimethyl sulfoxide (DMSO) and decrease the defects at the bottom of the perovskite film, which dramatically improves the device performance. The PCE of the device is increased from 18.03% to 20.78%, which is an increase of 15%. The work in this paper provides an effective method to enhance the performance of PSCs.

SnO2 is one of the most used inorganic electron transport materials for organic‐inorganic halide perovskite solar cells. However, the surface defects of SnO2 will block the electron transport at the SnO2/perovskite buried interface and limit the device performance. Here, poly(acrylic acid) (PAA) is employed to modify the SnO2 electron transport layer. Carboxyl groups can react with KOH in the commercial SnO2 aqueous colloidal dispersion to produce potassium polyacrylate, the −COO− can combine not only with oxygen and Sn4+ on SnO2, but also can chelate with uncoordinated Pb2+ defects on perovskite. Moreover, carboxyl groups can form a chemical linker between SnO2 and perovskite via the esterification reaction, leading to the reduction of surface hydroxyl group defects of SnO2. The optimal solar cells with PAA modification achieve an enhanced power conversion efficiency of 18.88 % and improved stability. [ABSTRACT FROM AUTHOR]

Low‐temperature solution processing of the perovskite layer enables the fabrication of flexible devices. However, the performance of flexible perovskite solar cells (f‐PSCs) lags far behind their rigid counterpart in terms of efficiency and stability. Emerging evidence demonstrates that the quality of the buried interface between perovskite and transporting layer underneath is the key point. Herein, a class of novel halide substituted ammonium salts, i.e., n‐bromophenethylammonium (n‐Br‐PEAX, n = 2 or 4, X = Cl or Br) are designed and synthesized to modify the buried interface as well as the perovskite crystallization of f‐PSCs. It is found that the ammonium salt with rational design molecular structure can modify the crystallization speed of perovskite, leading to the formation of a compact and uniform morphology without nanovoids at the interface. As a result, the efficiency of f‐PSCs is improved from 15.4% to 20.2%. Moreover, the modified devices without encapsulation retain 86% of their initial performance after 1000 h of aging at ambient conditions and 87% after 290 h of continuous operation. [ABSTRACT FROM AUTHOR]

A perovskite nucleation/growth compatible model via manipulating the intermediate complex induced by n -hexylamine (NHA) modulator is developed for efficient and ambient-air-stable PSCs. Comprehensive insights into the relevance between the precursor colloid, intermediate phase, and the crystallization of the perovskite have been elucidated in detail. [Display omitted] • Intermediate phase of MAPbI 3 was modulated by NHA for efficient and stable PSCs. • Nucleation/growth competition was finely relaxed by engineering the intermediate phase. • The device framework is reinforced due to the improved crystallization and hydrophobicity. • The PCE of the MAPbI 3 device increased to 21.91% with excellent stability. The smooth and dense light-absorbing layer is an essential factor in polycrystalline solar cells to achieve high photovoltaic performance, while it remains challenging in perovskite solar cells because of the difficulty balancing the speed of crystal nucleation and growth in a solution way. Here, we explored a perovskite nucleation/growth compatible model via manipulating the intermediate complex induced by n -hexylamine (NHA) molecule, guiding us to adjustments perovskite nucleation and growth process. We found that the NHA can act as a gearbox-like molecule to sequentially reduce the perovskite nucleation barrier, promote the nucleation velocity, and retard the perovskite growth simultaneously to obtain uniform perovskite films; correspondingly, this modulation also yields the buried interface with fewer voids and low defects density. In addition, the hydrophobic NHA with long alkyl chain improves the moisture tolerance of the perovskite. The treated solar cell power conversion efficiency was 21.91 %. Importantly, in ∼ 70 % humidity at 25 °C for 30 days, the efficiency of the device declined less than 5 %, exhibiting a good stability performance. [ABSTRACT FROM AUTHOR]

Perovskite films prepared by the solution process usually result in irregular grain orientation and rich buried interface defects, hindering the further improvement of device performance. Herein, multi‐fluorine‐containing C60‐ and C70 (higher fullerene)‐porphyrin derivatives, F60PD and F70PD, are synthesized and pre‐buried to modify the SnO2/perovskite heterointerface. The F70PD modification layer provides a better perovskite quality and more effective electron transporting capability compared to the corresponding F60PD, with the F70PD being more effective in regulating the perovskite growth, passivating the buried interface defects, and optimizing the interface energy level alignment. Consequently, the F70PD‐based device delivers superior efficiency and stability than the control and F60PD‐based devices. The F70PD‐based device yields a champion efficiency of 24.09% with negligible hysteresis. Meanwhile, due to the increased activation energy of ion migration, the F70PD‐based device maintains 80% of its initial efficiency after operating at the maximum power point for 1620 h. This study highlights the potential of designing higher fullerene materials for buried interface to further improve the perovskite solar cells' performance. [ABSTRACT FROM AUTHOR]

Light-induced phase segregation, particularly when incorporating bromine to widen the bandgap, presents significant challenges to the stability and commercialization of perovskite solar cells. This study explores the influence of hole transport layers, specifically poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine (PTAA) and [4-(3,6-dimethyl-9H-carbazol-9-yl)butyl]phosphonic acid (Me-4PACz), on the dynamics of phase segregation. Through detailed characterization of the buried interface, we demonstrate that Me-4PACz enhances perovskite photostability, surpassing the performance of PTAA. Nanoscale analyses using in situ Kelvin probe force microscopy and quantitative nanomechanical mapping techniques elucidate defect distribution at the buried interface during phase segregation, highlighting the critical role of substrate wettability in perovskite growth and interface integrity. The integration of these characterization techniques provides a thorough understanding of the impact of the buried bottom interface on perovskite growth and phase segregation.

Although perovskite solar cells (PSCs) are regarded as one of the most promising photovoltaic technologies, the interfacial defects and energy barrier are the main bottlenecks for further improving their photovoltaic performance and stability. Herein, an effective, facile "molecular bridge" strategy to improve the photovoltaic performance and stability of PSCs simultaneously is reported. This strategy is realized by introducing a self‐assembly molecule, namely, 5‐fluoro‐pyridine carboxylic acid (5‐FPA), to modify the SnO2/perovskite buried interface. The functional groups (F and CO) of 5‐FPA form strong chemical interactions with perovskite and SnO2 layers, which improve interfacial carrier extraction and perovskite film quality with better crystallization and less strain. As a result, photovoltaic performance is substantially improved with power conversion efficiencies exceeding 23%, accompanied by enhanced stability under thermal and ambient conditions. This study opens a new avenue to improve the performance and stability of perovskite photovoltaics through the "molecular bridge" strategy. [ABSTRACT FROM AUTHOR]

By converting the traditional solid–solid contact to solid–liquid contact, the buried interface of perovskite film is healed to release tensile strain and suppress halide segregation, which universally improves the efficiency and stability of a PSC. [Display omitted] • A universal liquid buried interface is fabricated to replace traditional solid–solid interface. • The weak van der Waals interaction releases the tensile strain. • A champion efficiency of 11.13 % and 14.05 % is achieved for CsPbIBr 2 and CsPbI 2 Br PSCs. • Suppressed halide segregation significantly improves the photostability of PSC. The residual tensile strain, which is induced by lattice and thermal expansion coefficient difference between upper perovskite film and underlying charge transporting layer, significantly deteriorates the power conversion efficiency (PCE) and stability of a halide perovskite solar cell (PSC). To overcome this technical bottleneck, herein, we propose a universal liquid buried interface (LBI) by introducing a low melting-point small molecule to replace traditional solid–solid interface. Arising from the movability upon solid-to-liquid phase conversion, LBI plays a role of "lubricant" to effectively free the soft perovskite lattice shrinkage or expansion rather than anchoring onto the substrate, leading to the reduced defects due to the healing of strained lattice. Finally, the inorganic CsPbIBr 2 PSC and CsPbI 2 Br cell achieve the best PCEs of 11.13 % and 14.05 %, respectively, and the photo-stability is improved by 33.3-fold because of the suppressed halide segregation. This work provides new insights on the LBI for making high-efficiency and stable PSC platforms. [ABSTRACT FROM AUTHOR]

[Display omitted] The defects and strain of the buried SnO 2 /perovskite interface seriously affects the performances of n -i-p type perovskite solar cells. Herein, caesium closo-dodecaborate (B 12 H 12 Cs 2) is introduced into buried interface to improve the device performances. B 12 H 12 Cs 2 can passivate the bilateral defects of the buried interface, including the oxygen vacancy and uncoordinated Sn2+ defects on SnO 2 side and the uncoordinated Pb2+ defects on perovskite side. Three-dimensional aromatic B 12 H 12 Cs 2 can promote the interface charge transfer and extraction. [B 12 H 12 ]2− can enhance the interface connection of buried interface by forming B-H---H-N dihydrogen bond and coordination bonds with metal ions. Meanwhile, the crystal properties of perovskite films can be improved and the buried tensile strain can be released by B 12 H 12 Cs 2 due to the matched lattice between B 12 H 12 Cs 2 and perovskite. In addition, Cs+ can diffuse into perovskite to reduce the hysteresis behavior by inhibiting the I− migration. Arising from the enhanced connection performances, passivated defects, improved perovskite crystallization, enhanced charge extraction, inhibited ions migration, released tensile strain at buried interface by B 12 H 12 Cs 2 , the corresponding devices yield a champion power conversion efficiency of 22.10% with enhanced stability. The stability of devices by B 12 H 12 Cs 2 modification have been improved, and it can still maintain 72.5% of the original efficiency after 1440 h, while the control devices can only maintain 20% of the original efficiency after aging in air condition of 20–30% RH. [ABSTRACT FROM AUTHOR]

Easy‐to‐form tin vacancies at the buried interface of tin‐lead perovskites hinder the performance of low‐bandgap perovskite solar cells (PSCs). Here, a synergistic strategy by incorporating potassium citrate (PC) into the poly(3,4‐ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) hole‐transport layer to passivate the buried interface of Sn‐Pb PSCs is reported. PC neutralizes the acidity of PEDOT:PSS and stabilizes the perovskite front surface, enhancing device stability. Citrate moieties coordinate with Sn2+ on the buried perovskite surface, preventing Sn2+ oxidation and suppressing defect formation. Additionally, potassium cations incorporate into Sn‐Pb perovskites, enhancing crystallinity and passivating halide defects. The combined benefits enable efficient low‐bandgap Sn‐Pb PSCs with a power conversion efficiency of 22.7% and a high open‐circuit voltage of 0.894 V. Using this method, 26.1% efficiency for all‐perovskite tandem solar cells is demonstrated. These results emphasize the significance of buried interface passivation in developing efficient and stable Sn‐Pb PSCs and all‐perovskite tandem solar cells. [ABSTRACT FROM AUTHOR]

The interface of perovskite solar cells (PSCs) is significantly important for charge transfer and device stability, while the buried interface with the impact on perovskite film growth has been paid less attention. Herein, we use a molecular modifier, glycocyamine (GDA) to build a molecular bridge on the buried interface of SnO2/perovskite, resulting in superior interfacial contact. This is achieved through the strongly interaction between GDA and SnO2, which also appreciably modulates the energy level. Moreover, GDA can regulate the perovskite crystal growth, yielding perovskite film with enlarged grain size and absence of pinholes, exhibiting substantially reduced defect density. Consequently, PSCs with GDA modification demonstrate significant improvement of open circuit voltage (close to 1.2 V) and fill factor, leading to an improved power conversion efficiency from 22.60 % to 24.70 %. Additionally, stabilities of GDA devices under maximum power point and 85 °C heat both perform better than the control devices. [ABSTRACT FROM AUTHOR]

The phase segregation of wide-bandgap perovskite is detrimental to a device’s performance. We find that Sodium Benzenesulfonate (SBS) can improve the interface passivation of PTAA, thus addressing the poor wettability issue of poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine](PTAA). This improvement helps mitigate interface defects caused by poor contact between the perovskite and PTAA, reducing non-radiative recombination. Additionally, enhanced interface contact improves the crystallinity of the perovskite, leading to higher-quality perovskite films. By synergistically controlling the crystallization and trap passivation to reduce the phase segregation, SBS-modified perovskite solar cells (PSCs) achieved a power conversion efficiency (PCE) of 20.27%, with an open-circuit voltage (Voc) of 1.18 V, short-circuit current density (Jsc) of 20.93 mA cm−2, and fill factor (FF) of 82.31%.

The performance of perovskite light-emitting diodes (PeLEDs) has been drastically improved recently. Therein, the coexistence of polydisperse perovskite domains has been one worthy subject of study. The crystallization of perovskite is affected by the buried interface character with the bottom contact layer; and the trap states also inherently exist at the buried interface of the perovskite film, which induce the nonradiative recombination and impede the PeLED performance. In this work, we focus on the crystallization modulation of monodisperse perovskite nanodomains toward high-performance PeLEDs. We show that a LiBr pre-modification layer on the bottom substrate induces the formation of monodisperse perovskite phase. In this system, the carrier transferring process deriving from the polydisperse phases is reduced. In addition, the LiBr pre-modification layer at the buried interface minimizes the trap states and enhances the radiative recombination of perovskites. Accordingly, our PeLEDs show a champion external quantum efficiency (EQE) of 25.5% for 4 mm2 device, and 22.9% for 100 mm2 device.

Perovskite solar cells (PSCs) have been developed rapidly in recent years because of their excellent photoelectric performance. However, interfacial non-radiative recombination hinders the improvement of device performance. The buried interface modification strategy can minimize the non-radiation recombination in the interface and can obtain the high efficiency and stability of PSCs. In this review, we introduce the device structure and the charge carrier dynamics (charge transfer, extraction, and collection) at the interface. We further summarize the main sources of non-radiative recombination at the interface, such as energy alignment mismatch and interface defects, and methods to characterize them. In contrast to the previous review of perovskite solar cells, the important roles of buried interfaces in regulating energy level alignment, passivating surface defects, modulating morphology, and so on are reviewed in detail based on the latest research, and strategies for reducing interfacial nonradiative recombination are provided. In the end, the potential development and challenges of buried interfaces for high-performance and stable PSCs are presented. [ABSTRACT FROM AUTHOR]

Highlights An effective buried interface stabilization strategy based on synergistic effect of fluorine and sulfonyl functional groups is proposed. The correlations between molecular structures, defect passivation, interfacial energy band alignment, perovskite crystallization and device performance are established. The device with KFSI achieves an impressive efficiency of 24.17%.

Focused ion beam (FIB) is commonly used as a standard machining technique in failure analysis, quality control, reverse engineering, material research, and so on, for the samples having microstructures and nanostructures. FIB combined with time‐of‐flight secondary ion mass spectrometry (TOF‐SIMS), so‐called FIB‐TOF, has attracted attention as a method to determine the three‐dimensional (3D) chemical distributions of complex samples. In general, a highly focused Ga+ ion beam is used for FIB, however, the FIB‐milled area is limited and it was difficult to expand the Ga‐FIB to hundreds of micron length scale for sample fabrication. In order to overcome the drawback, we proposed the Bi‐FIB approach for large scale sample cross‐sectioning. Although the possibility of Bi‐FIB has been reported, there were almost no performance examinations as well as practical applications. In this study, therefore, the authors summarize the comparison of milling rate and milling damage between Ga‐FIB and Bi‐FIB. As a result, it was found that Bi‐FIB can provide a higher milling rate with thinner milling damage. Finally, the Bi‐FIB approach was applied to the interfacial analysis of all‐solid‐state battery (ASSB) material. With this approach, the detailed chemical distributions at the interface were discovered, leading to the better understanding of battery behaviors. [ABSTRACT FROM AUTHOR]

Interface band dispersion of a MgO(2 nm)/Fe(50 nm) heterostructure was detected by hard X-ray angle-resolved photoemission spectroscopy (HARPES) with the excitation photon energy of 3.29 keV by utilizing X-ray total reflection (TR). By subtracting bulk-sensitive band dispersion of the buried Fe(001) obtained by HARPES in the non-TR condition from near-interface-sensitive Fe(001) band dispersion obtained by TR-HARPES, the band-folding of Fe and the O 2 p -Fe 3 d hybridization at the heterointerface were clearly unveiled. These results suggest that HARPES can probe not only the bulk band but also the buried interface band of heterojunctions.

Highlights: An effective buried interface stabilization strategy based on synergistic effect of fluorine and sulfonyl functional groups is proposed. The correlations between molecular structures, defect passivation, interfacial energy band alignment, perovskite crystallization and device performance are established. The device with KFSI achieves an impressive efficiency of 24.17%. The interfacial defects and energy barrier are main reasons for interfacial nonradiative recombination. In addition, poor perovskite crystallization and incomplete conversion of PbI2 to perovskite restrict further enhancement of the photovoltaic performance of the devices using sequential deposition. Herein, a buried interface stabilization strategy that relies on the synergy of fluorine (F) and sulfonyl (S=O) functional groups is proposed. A series of potassium salts containing halide and non-halogen anions are employed to modify SnO2/perovskite buried interface. Multiple chemical bonds including hydrogen bond, coordination bond and ionic bond are realized, which strengthens interfacial contact and defect passivation effect. The chemical interaction between modification molecules and perovskite along with SnO2 heightens incessantly as the number of S=O and F augments. The chemical interaction strength between modifiers and perovskite as well as SnO2 gradually increases with the increase in the number of S=O and F. The defect passivation effect is positively correlated with the chemical interaction strength. The crystallization kinetics is regulated through the compromise between chemical interaction strength and wettability of substrates. Compared with Cl−, all non-halogen anions perform better in crystallization optimization, energy band regulation and defect passivation. The device with potassium bis (fluorosulfonyl) imide achieves a tempting efficiency of 24.17%. [ABSTRACT FROM AUTHOR]

[Display omitted] • A novel zwitterionic bridging strategy is proposed to passivate bifacial defects. • The planar conjugated structure of GUP enhances the structural stability of perovskite and releases residual stresses. • The optimized PSCs exhibited an increase in PCE from 21.23% to 24.03%, with an open-circuit voltage of up to 1.172 V • The multifunctional flame retardant facilitates bridging between ETL and perovskite, enhancing the stability of PSCs. Buried interface defects and residual stresses significantly impede further improvements in the efficiency and stability of perovskite solar cells (PSCs). Herein, a flame retardant guanylurea phosphate (GUP) with multisite anchors serves as the zwitterionic bridge between SnO 2 and perovskite. The phosphate groups within GUP facilitate bridging between SnO 2 and perovskite while concomitantly passivating bifacial defects, thereby significantly inhibiting non-radiative recombination at the buried interface. Simultaneously, the planar configuration of the amidinourea unit strengthens the binding of amino (–NH 2) and carbonyl (C=O) groups with [PbI 6 ]4−, which enhances perovskite structure stability and relieves residual stresses. Contributing to the zwitterionic bridging strategy of multi-functional flame retardant, the power conversion efficiency (PCE) of GUP-treated PSCs significantly increased from 21.23 % to 24.03 %, with an open-circuit voltage (V OC) of up to 1.172 V, and exhibited outstanding stability. Unencapsulated PSCs treated with GUP maintained about 93.86 % and 80.53 % of their original efficiency after 1200 h of aging in the air at 25 °C with 25 ± 5 % relative humidity (RH) and after 600 h of aging in the air at 85 °C and 10 ± 5 % RH, respectively. [ABSTRACT FROM AUTHOR]

In the study of high efficiency perovskite solar cells (PSCs), the improvement of device efficiency and stability is still limited by interface and bulk defects. In this work, a new regulation strategy is proposed, that organic sulfonate additives are introduced into the interface and perovskite film of PSCs respectively to obtain higher performance. Firstly, potassium methanesulfonate (KMsO) has acted as a multifunctional additive to passivate the surface defects of SnO 2 and improve the morphology and reduce the defect density of the bottom surface of perovskite (PVSK) films. Furthermore, sodium pyridine-3-sulphonate (SP3S) has been added to the precursor of perovskite that can effectively passivate the bulk defects and improve crystallinity. This has been realized by the interactions among the sulfonate groups and pyridine groups with perovskite. Finally, the device optimized by KMsO and SP3S exhibits higher repeatability and average efficiency. The champion device has shown power conversion efficiency (PCE) of 23.8 %. What's more, the unencapsulated device has still remained 90.8 % of the initial efficiency after storage of 1000 h at 25 °C and ∼30 %RH, while the control device has remained only 62.4 % under the same condition. These results have in general revealed a facile passivation strategy for the perovskite solar cells with composite mechanism with quite good tunability and controllability for future applications. • Dual additive engineering improves PSCs performance. • Sulfonate additives improve the bottom surface topography and enhance carrier transport. • Hydrogen and coordination bonds enhance perovskite crystallization. • A champion device efficiency of 23.8 % is achieved. [ABSTRACT FROM AUTHOR]

[Display omitted] • A molecular bridge between the perovskite layer and SnO 2 is established using 4DBA. • Oxygen vacancies in SnO 2 are passivated by 4DBA, leading to enhanced conductivity. • 4DBA enhances perovskite crystallization and passivates the buried interface defects. • 4DBA improves energy level alignment at the SnO 2 /perovskite interface. • Unsealed CsPbBr 3 PSC achieves a best PCE of 10.78% and high moisture-heat stability. The enhancement of power conversion efficiency (PCE) of perovskite solar cells (PSCs) is critically affected by charge recombination induced by buried interface defects. In light of this, a simple and effective target therapy strategy has been developed by doping 4-(diphenylphosphino)benzoic acid (4DBA) molecules at the tin oxide (SnO 2)/perovskite interface. The effects of 4DBA on carrier transport, perovskite growth, defect passivation, and PSCs properties were systematically investigated. It is illustrated that 4DBA molecules not only passivate oxygen vacancy (O V) defects on the SnO 2 surface, enhancing the conductivity of the SnO 2 film and accelerating electron transfer, but also passivate perovskite interface defects, thereby improving the quality of the perovskite film. Ultimately, the efficiency of CsPbBr 3 device with 4DBA-modified buried interface increased from 8.87% to 10.78%, an improvement of 21.53%. Furthermore, the efficiency of CsPbI 2 Br increased from 12.83% to 14.44%, an improvement of 12.55%, further demonstrating the effectiveness and universality of this strategy. Excitingly, the unencapsulated PSCs exhibit excellent long-term stability under high relative humidity and high temperatures. [ABSTRACT FROM AUTHOR]

[Display omitted] • Robust transporting layers do not guarantee durable perovskite solar cells. • Vapor deposition promotes the structural orientation of perovskite polycrystal. • Surface polarity dictates perovskite crystallography by precursor adhesion property. • Buried interface has a profound influence on perovskite photostability. • Passivation-free perovskite solar cells maintain 80 % efficiency after 47 days of light exposure. All-vapor-deposited perovskite solar cells (PSCs) offer promising potential for maintaining high efficiency across large-area solar modules. However, a comprehensive understanding of device stability, particularly the crucial photodegradation mechanism under sunlight exposure, remains scarce in the existing literature. In this study, we investigate thermally co-evaporated perovskite polycrystals grown on two typical organic hole-transporting layers (HTLs), macrocyclic copper (Ⅱ) phthalocyanine (CuPc) and the arylamine derivative of N4,N4,N4′,N4′-tetra([1,1′-biphenyl]-4-yl)-[1,1′:4′,1′-terphenyl]-4,4′-diamine (TaTm). Surprisingly, the robust CuPc limits the device performance with substantial non-radiative recombination loss and accelerates device degradation under light exposure. When built upon TaTm, the PSCs demonstrate a 47 times prolonged T 80 lifetime (the efficiency drops to 80 % of the initial efficiency) of 1128 h by regulating the surface crystallography. By reducing the perovskite thickness to approach the buried heterojunction interface, we unravel the loss mechanism by directly observing crystallization dynamics. Our investigation reveals that surface polarity significantly influences the precursor adhesion, grain growth, and recombination dynamics at the HTL-perovskite interface. These findings underscore the critical role of the underlying surface in vapor-deposited PSCs, highlighting the potential for improved photostability through the regulation of interface imperfections. [ABSTRACT FROM AUTHOR]