FAPbI3 Perovskite Research Articles

A Stepwise Melting-Polymerizing Molecule for Hydrophobic Grain-Scale Encapsulated Perovskite Solar Cell.

Despite the ongoing increase in the efficiency of perovskite solar cells, the stability issues of perovskite have been a significant hindrance to its commercialization. In response to this challenge, a stepwise melting-polymerizing molecule (SMPM) is designed as an additive into FAPbI3 perovskite. SMPM undergoes a three-stage phase transition during the perovskite annealing process: initially melting from solid to liquid state, followed by overflowing grain boundaries, and finally self-polymerizing to form a hydrophobic grain-scale encapsulation in perovskite solar cells, providing protection against humidity-induced degradation. With this unique property, coupled with the advantages of improved crystallization, diminished non-radiative recombination, and energy level alignment, FAPbI3-based perovskite solar cells with a 25.21% (small-area) and 22.94% (1 cm2) power conversion efficiency and over 2000 h T95% stability under 85% relative humidity is achieved. Furthermore, the SMPM-based perovskite solar cells without external encapsulations sustain impressive stability during underwater operation, in which the black FAPbI3 phase is maintained and Pb-leakage is also effectively suppressed. Therefore, the SMPM strategy can offer a sustainable settlement in both stability and environmental issues for the commercialization of perovskite solar cells.

Rational design of spacer cations toward efficient and stable 2D/3D heterostructure perovskite solar cells

The integration of 2D and 3D perovskite materials can enhance the stability and efficiency of perovskite solar cells. This study examines the impact of modifying common organic spacers—2AI, PEA, and FPEA—with formamidinium (FA), guanidinium (GA), and methylenediammonium (MDA) cations on the interface between 2D and 3D layers in FAPbI3 perovskite materials. Structural analysis, electrostatic mapping, and energy calculations reveal that GA modification strengthens binding but destabilizes stacking, while MDA modification improves stability and charge transfer. These findings offer valuable insights into optimizing organic spacer modifications for 2D/3D perovskite solar cell performance.

Challenges and opportunities in high efficiency scalable and stable perovskite solar cells

Perovskite solar cells (PSCs) are the fastest-growing photovoltaic (PV) technology and hold great promise for the photovoltaic industry due to their low-cost fabrication and excellent efficiency. To achieve commercial readiness level, the most important factor would be yield beyond 95% at the PSC module levels. The current essential requirements for PSCs are reproducibility of high efficiency devices, scalability, and stability. The reported certified high efficiency (24–26%) results are based on the use of FAPbI3 perovskites with a bandgap of Eg≈ 1.5 eV, and the typical device's active area ranges from ≈ 0.1 cm2 to a maximum of 1 cm2. However, relatively higher bandgap PSCs are essential, especially in tandem solar cell applications. Hence, optimization of higher bandgap PSCs is a necessity. As the bandgap of the perovskites increases, the efficiency goes down due to reduced JSC and increased VOC loss. Therefore, understanding the loss mechanism and corresponding solutions need to be developed. Scaling up the device's active area without compromising the fill factor and, hence, efficiency is non-trivial. So, understanding the loss mechanism in large area devices is crucial. The stability analysis reported in the literature is inconsistent, preventing data comparison and identifying various degradation factors or failure mechanisms. Moreover, how the accelerated tests would be useful in predicting the real lifetime of the solar cells is yet to be developed. So, understanding the knowledge and the technological gaps between laboratory and industry-scale production is crucial for further development. Therefore, in this review article, we discuss the challenges and opportunities for scalable and stable high efficiency PSCs.

Enhancing Performance and Stability of Perovskite Solar Cells with a Novel Formamidine Group Additive.

Perovskite materials, particularly FAPbI3, have emerged as promising candidates for solar energy conversion applications. However, these materials are plagued by well-known defects and suboptimal film quality. Enhancing crystallinity and minimizing defect density are therefore essential steps in the development of high-performance perovskite solar cells. In this study, 1H-Pyrazole-1-carboximidamide hydrochloride (PCH) is introduced into FAPbI3 perovskite films. The molecular structure of PCH features a pyrazole ring bonded to formamidine (FA). The FA moiety of PCH facilitated the incorporation of this additive into the film lattice, while the negatively charged pyrazole ring effectively passivated positively charged iodine vacancies. The presence of PCH led to the fabrication of an FAPbI3 device with improved crystallinity, a smoother surface, and reduced defect density, resulting in enhanced Voc and fill factor. A record power conversion efficiency of 24.62% is achieved, along with exceptional stability under prolonged air exposure and thermal stress. The findings highlight the efficacy of PCH as a novel additive for the development of high-performance perovskite solar cells.

Superior stabilized α-FAPbI3 perovskite solar cells with efficiency exceeding 24 %

-Fabrication of a stabilized black phase of formamidinium triiodide perovskite film is a critical issue to warrant efficient perovskite solar cells with considerable intrinsic and external stability. To address this obstacle, the study focuses on assembling α-FAPbI3 perovskite solar cells. To realize a stabilized α-FAPbI3, a δ-FAPbI3 film was annealed at 150 °C at ambient air with a humidity level of 25 % to convert α-FAPbI3. Then, this δ→α FAPbI3 was crushed, and some of it was added to a fresh FAPbI3 perovskite precursor to fabricate desirable α-FAPbI3 layers. The cost-effective method, along with the stabilization of α-FAPbI3, showed a high ability to promote charge transfer and suppress trap transitions in the perovskite layer. The engineered perovskite solar cells recorded a considerable filling factor of 82.89 % with a champion efficiency of 24.16 %, higher than the recorded efficiency of 21.25 %. In addition, the robust stability enables the FAPbI3 solar cells to work steadily for more than 1200 h under simulated sunlight irradiance with just an 8 % loss in their performance.

Preferentially coordinating tin ions to suppress composition segregation for high-performance tin-lead mixed perovskite solar cells

Tin-lead mixed perovskites (TLPs) with a tunable and ideal bandgap exhibit great potential in approaching the Shockley–Queisser limit of power conversion efficiency (PCE). However, two critical issues are necessary to be addressed, including the oxidation of Sn2+ and negligible composition and phase segregation. The latter derives from the unbalanced crystallization rate between Sn- and Pb-based perovskites. Here, we report a strategy to address the above critical issues by introducing 3,4-Dihydroxybenzylamine hydrobromide (DHBABr) in the TLP precursor solution. DHBABr was revealed to promote the crystallization of FAPbI3 perovskite by suppressing the formation of crystalline DMSO-FA-Pb-I intermediates and retard the crystallization rate of FASnI3 by preferentially forming a steady amorphous DHBA-FA-Sn-I intermediate. This, therefore, balances the crystallization rate between Sn- and Pb-based perovskites. As a result, the spatial distribution of Sn/Pb ratio is much more uniform across the whole TLP film, which benefits the upscaling of the manufacturing process. Relying on this doping strategy accompanied by the surface passivation with DHBABr, which reduces the defect density of TLP, inhibits the oxidation of Sn2+, and optimizes the band alignment of the device, we have achieved a PCE of 22.44 % with Voc of 0.853 V and FF of 80.0 %, along with an enhanced long-term stability of T80 = 476 h under continuously light illumination in the champion device.

Low-Cost, Scalable Fabrication of Multi-Dimensional Perovskite Solar Cells and Modules Assisted by Mechanical Scribing.

The performance and scalability of perovskite solar cells (PSCs) based on 3D formamidinium lead triiodide (FAPbI3) absorber are often hindered by defects at the surface and grain boundaries of the perovskite. To address this, the study demonstrates the use of pyrrolidinium iodide for the in situ formation of an energetically aligned 1D pyrrolidinium lead triiodide (PyPbI3) capping layer over the 3D FAbI3 perovskite. The thermodynamically stable PyPbI3 perovskitoids, formed through cation exchange reactions, effectively reduce surface and grain boundary defects in the FAPbI3 perovskite. In addition to improved phase stability, the resulting 1D/3D perovskite film forms a cascade energy band alignment with the other functional layers in PSCs, enabling a barrier-free interfacial charge transport. With a maximum power conversion efficiency (PCE) of ≈23.1% and ≈20.7% at active areas of 0.09 and 1.05 cm2, respectively, the 1D/3D PSCs demonstrate excellent performance and scalability. Leveraging this improved scalability, the study has successfully developed a mechanically-scribed 1D/3D perovskite mini-module with an unprecedentedly high PCE of ≈20.6% and a total power output of ≈270mW at an active area of ≈13.0 cm2. The 1D/3D multi-dimensional perovskite film developed herein holds great promise for producing low-cost, high-performance perovskite photovoltaics at both the cell and module levels.

Flexible optoelectronic N-I-P synaptic device with visible spectrum perception for energy-efficient artificial vision and efferent neuromuscular system

We have designed a flexible photoelectric artificial synapse with an oxide/mixed perovskite/polymer N-I-P structure that exhibits essential synaptic plasticity. Formamidinium lead triiodide FAPbI3 perovskite doped with bromine and methylammonium (FAxMA1−xPbI2Br) is employed as the intrinsic layer to improve the optical properties of devices. Without requiring a power source in reaction to outside optical spikes, multiple pulse-dependent plasticity is reproduced on the synaptic devices, and the image's edges are sharpened using high-pass filtering. Additionally, the classical conditioning and spatiotemporal learning are copied under the electric pulse excitation. Significant negative differential resistance is evident, even after 1500 flex/flat mechanical operation. The recognition rate of letters in the visual system is as high as 92%, and the walking distance in the efferent neuromuscular system is controllable. The flexible optoelectronic N-I-P synaptic device is designed to facilitate energy-efficient information processing for neuromorphic computing.

New Insights into MAI Additives in 2D-Assisted 3D Controlled Crystallization Toward High-Quality α-Phase FAPbI3 Perovskites.

The highly oriented 2D perovskite templates of n = 1 have typically been created to attain controllable and oriented crystallization of 3D α-phase formamidinium lead triiodide (α-FAPbI3) perovskites. However, the role of methylammonium iodide (MAI), a widely used α-FAPbI3 phase stabilizer, in regulating the growth dynamics of 2D/3D perovskites is generally ignored. Herein, Ruddlesden-Popper type n = 1 2D octylammonium lead iodide(OA2PbI4) perovskites are added into FAPbI3 precursor solution. The template of n = 2 (OA2MAPb2I7), which is spontaneously constructed by the mixture of n = 1 2D and methylammonium chloride (MACl), acts as a skeleton to template the epitaxial growth of α-FAPbI3. However, the volatilization of MACl inevitably causes damage to the 2D structure during thermal annealing. This study reveals that small amounts of less volatile MAI additive enables the creation of stable 2D template, leading to more controlled vertical orientation crystallization. Consequently, the high-quality mixed-dimensional perovskite film delivers a high efficiency of 24.19% together with improved intrinsic stability. This work provides an in-depth understanding of 2D-assisted controlled epitaxial growth of α-FAPbI3.

WS2 monolayer integration in a FAPbI3-based heterostructure

Incorporating a monolayer of WS2 via interface engineering enhances the overall physical properties of a FAPbI3 perovskite based heterostructure. FAPbI3/WS2/TiO2/ITO and FAPbI3/TiO2/ITO heterostructures were analyzed by UV–Vis spectroscopy, x-ray diffraction, scanning electron microscopy, and atomic force microscopy. The configuration with WS2 interlayer presents higher absorption in the visible region with a bandgap of ∼1.45 eV. WS2 also enhances the deposition process of FAPbI3, resulting in the formation of pure photoactive α-phase without the non-photoactive δ-phase or residual plumbates. The incorporation of the monolayer improves the crystalline structure of the FAPbI3, promoting a preferential growth in the [100] direction. The smooth surface of WS2 favors a homogeneous morphology and an increase in the grain size to ∼4.5 μm, the largest reported for similar structures. Furthermore, the work function obtained lets us propose an enhanced an adequate energy band alignment between FAPbI3 and the n-type layers for the electron flux to the cathode. Conductivity and IV curves show a better performance with WS2. These findings strongly suggest that the interfacial coupling of FAPbI3/WS2 could be a promising candidate in photovoltaic applications.

Lead-Chelating Intermediate for Air-Processed Phase-Pure FAPbI3 Perovskite Solar Cells.

Formamidinium-lead triiodide (FAPbI3) perovskite holds promise as a prime candidate in the realm of perovskite photovoltaics. However, the photo-active α-FAPbI3 phase, existing as a metastable state, is observable solely at elevated temperatures and is susceptible to degradation into the δ-phase in ambient air. Therefore, the attainment of phase-stable α-FAPbI3 in ambient conditions has become a crucial objective in perovskite research. Here, we proposed an efficient conversion process of PbI2 into the α-FAPbI3 perovskites in ambient air. This conversion was facilitated by the introduction of chelating molecules, which interacted with PbI2 to form an intermediate phase. Due to the reduced formation barrier resulting from the altered reaction pathway, this stable intermediate phase transitioned directly into α-FAPbI3 upon the deposition of the organic cation solution, effectively bypassing the formation of δ-FAPbI3. Consequently, the ambient-fabricated FAPbI3 perovskite solar cells (PSCs) exhibited an outstanding power conversion efficiency of 25.08 %, along with a high open-circuit voltage of 1.19 V. Furthermore, the unencapsulated devices demonstrated remarkable environmental stability. Notably, this innovative approach promises broad applicability across various chelating molecules, opening new avenues for further progress in the ambient air fabrication of FAPbI3 PSCs.

Lead‐Chelating Intermediate for Air‐Processed Phase‐Pure FAPbI3 Perovskite Solar Cells

AbstractFormamidinium‐lead triiodide (FAPbI3) perovskite holds promise as a prime candidate in the realm of perovskite photovoltaics. However, the photo‐active α‐FAPbI3 phase, existing as a metastable state, is observable solely at elevated temperatures and is susceptible to degradation into the δ‐phase in ambient air. Therefore, the attainment of phase‐stable α‐FAPbI3 in ambient conditions has become a crucial objective in perovskite research. Here, we proposed an efficient conversion process of PbI2 into the α‐FAPbI3 perovskites in ambient air. This conversion was facilitated by the introduction of chelating molecules, which interacted with PbI2 to form an intermediate phase. Due to the reduced formation barrier resulting from the altered reaction pathway, this stable intermediate phase transitioned directly into α‐FAPbI3 upon the deposition of the organic cation solution, effectively bypassing the formation of δ‐FAPbI3. Consequently, the ambient‐fabricated FAPbI3 perovskite solar cells (PSCs) exhibited an outstanding power conversion efficiency of 25.08 %, along with a high open‐circuit voltage of 1.19 V. Furthermore, the unencapsulated devices demonstrated remarkable environmental stability. Notably, this innovative approach promises broad applicability across various chelating molecules, opening new avenues for further progress in the ambient air fabrication of FAPbI3 PSCs.

Blade-Coating (100)-Oriented α-FAPbI3 Perovskite Films via Crystal Surface Energy Regulation for Efficient and Stable Inverted Perovskite Photovoltaics.

Photoactive black-phase formamidinium lead triiodide (α-FAPbI3) perovskite has dominated the prevailing high-performance perovskite solar cells (PSCs), normally for those spin-coated, conventional n-i-p structured devices. Unfortunately, α-FAPbI3 has not been made full use of its advantages in inverted p-i-n structured PSCs fabricated via blade-coating techniques owing to uncontrollable crystallization kinetics and complicated phase evolution of FAPbI3 perovskites during film formation. Herein, a customized crystal surface energy regulation strategy has been innovatively developed by incorporating 0.5 mol % of N-aminoethylpiperazine hydroiodide (NAPI) additive into α-FAPbI3 crystal-derived perovskite ink, which enabled the formation of highly-oriented α-FAPbI3 films. We deciphered the phase transformation mechanisms and crystallization kinetics of blade-coated α-FAPbI3 perovskite films via combining a series of in-situ characterizations and theoretical calculations. Interestingly, the strong chemical interactions between the NAPI and inorganic Pb-I framework help to reduce the surface energy of (100) crystal plane by 42 %, retard the crystallization rate and lower the formation energy of α-FAPbI3. Benefited from multifaceted advantages of promoted charge extraction and suppressed non-radiative recombination, the resultant blade-coated inverted PSCs based on (100)-oriented α-FAPbI3 perovskite films realized promising efficiencies up to 24.16 % (~26.5 % higher than that of the randomly-oriented counterparts), accompanied by improved operational stability. This result represented one of the best performances reported to date for FAPbI3-based inverted PSCs fabricated via scalable deposition methods.

Blade‐Coating (100)‐Oriented α‐FAPbI3 Perovskite Films via Crystal Surface Energy Regulation for Efficient and Stable Inverted Perovskite Photovoltaics

Photoactive formamidinium lead triiodide (α‐FAPbI3) perovskite has dominated the prevailing high‐performance perovskite solar cells (PSCs), normally for those spin‐coated, conventional n‐i‐p structured devices. Unfortunately, α‐FAPbI3 has not been made full use of its advantages in inverted p‐i‐n structured PSCs fabricated via blade‐coating techniques owing to uncontrollable crystallization kinetics and complicated phase evolution of FAPbI3 perovskites. Herein, a customized crystal surface energy regulation strategy has been innovatively developed by incorporating 0.5 mol% of N‐aminoethylpiperazine hydroiodide (NAPI) additive into α‐FAPbI3 crystal‐derived perovskite ink, which enabled the formation of phase‐pure, highly‐oriented α‐FAPbI3 films. We deciphered the phase transformation mechanisms and crystallization kinetics of blade‐coated α‐FAPbI3 perovskite films via combining a series of in‐situ characterizations. Interestingly, the strong chemical interactions between the NAPI and inorganic Pb‐I framework help to reduce the surface energy of (100) crystal plane by 42%, retard the crystallization rate and lower the formation energy of α‐FAPbI3. The resultant blade‐coated inverted PSCs based on (100)‐oriented α‐FAPbI3 perovskite films realized promising efficiencies up to 24.16% (~26.5% higher than that of the randomly‐oriented counterparts), accompanied by improved operational stability. This result represented one of the best performances reported to date for FAPbI3‐based inverted PSCs fabricated via scalable deposition methods.

Controlled dion-jacobson low-dimensional surface phase enables highly efficient and stable perovskite solar cells

The 2D/3D heterojunction structure emerges as a viable approach for enhancing the efficiency and stability of perovskite photovoltaics. However, the formation of an accumulative low-dimensional 2D perovskite (n=1) cladding layer often impedes carrier transport due to the insulating nature and high quantum confinement, and there is a paucity of detailed understanding regarding its surface phase control. This study introduces a Dion-Jacobson (DJ) phase 2D perovskite, employing decane-1,10-diammonium diiodide (DDADI) to interface with 3D perovskite, leveraging long-chain diammonium cations for structural stability and defect passivation on the 3D FAPbI3 perovskite surface. In addition, a novel PbI2-assisted phase control (PAPC) technique is proposed to mitigate the quantum confinement effects of the 2D layer, especially reducing the formation of the highly confined insulating n=1 phase. X-ray scattering analysis confirms the method's efficacy in promoting the formation of an n=2 phase, facilitating cascading HOMO levels and improving hole carrier transport. The optimized 2D/3D perovskite solar cell (PSC) achieve an exemplary efficiency of 25.16 %, with a notable open-circuit voltage of 1.192 V, and retain 92.9 % of its initial efficiency after 1000 hours in a nitrogen atmosphere, signifying a strategic advancement in 2D/3D PSC construction.

Improvement in stability of perovskite solar cells by adlayer of laser treated FAPbI3 quantum dots

Perovskite solar cells have emerged as a promising technology for renewable energy generation due to their potential of high-efficiency and low-cost fabrication. However, their stability under environmental stressors such as humidity and light exposure remains a critical challenge for widespread commercialization. This study investigates the use of FAPbI3 quantum dots (QDs) synthesized in a colloidal solution as adlayer on top of the FAPbI3 bulk light absorbing layer. Our main findings reveal that incorporating such an adlayer composed of FAPbI3 QDs significantly improves the stability of FAPbI3 films and devices against humidity and light-induced degradation. Furthermore, it is demonstrated that a femtosecond (fs) laser treatment in a colloidal solution provides significant surface modification of FAPbI3 QDs. By using such a treated FAPbI3 QDs as adlayer, the devices exhibit power conversion efficiencies exceeding 20 % with improved stability, highlighting their potential for practical applications. This study offers valuable insights into leveraging QDs and the post laser treatment to enhance the stability and efficiency of FAPbI3 perovskite solar cells within a monomaterial system, paving the way for the development of durable and high-performance photovoltaic devices.

Manipulating the Crystallization of Perovskite via Metal‐Free DABCO‐NH4Cl3 Addition for High Efficiency Solar Cells

AbstractThe performance of perovskite cells closely relies on the quality of films, leading to a special focus on crystallization manipulation and defect control. In this study, a novel approach using 1D metal‐free perovskites, specifically DABCO‐NH4Cl3, is proposed to facilitate the crystallization process of 3D FAPbI3 perovskites, while simultaneously addressing surface defects. Analysis of crystallization kinetics reveals that the introduction of 1D metal‐free perovskites provides numerous nucleation sites, effectively slowing down crystal growth rates and resulting in the formation of uniform, large‐grain perovskite films. Furthermore, the organic groups present in 1D perovskites play a crucial role in passivating defects within the perovskite structure. The synergistic impact of these factors enables the perovskite to achieve an efficiency of 24.72% while demonstrating exceptional stability. This research offers a promising approach for controlling perovskite crystallization, leading to the development of high‐efficiency and stable perovskite materials.

Gradient Dion‐Jacobson Phase Stable Quasi‐2D Perovskite@Graphene Hybrid for High Responsivity Photodetectors

AbstractQuasi‐(2D) formamidinium lead‐iodide (FAPbI3) perovskites are winsome materials for high‐performance photodetectors (PDs). Between Ruddlesden‐Popper (RP) and Dion‐Jacobson (DJ) phases, the latter exhibits lower non‐radiative recombination and higher mobility compared to the relatively easily synthesized former. For efficient charge separation and transport, graphene‐assisted two‐terminal coplanar PD leveraging the DJ phase perovskite is proposed. Diamino octane (DAO), incorporated into 3D FAPbI3 perovskite, resulted in DJ phase [DAO(FA)n‐1PbnI3n+1], n being predefined integers 1≤ n ≤ ∞, demonstrating a vertical gradient heterostructure of n phases. Superior crystallinity and thermal stability of the quasi‐2D films are confirmed via synchrotron‐based studies. Band‐edge of the 3D film blue‐shifted consistently from 810 nm, while passing through the quasi‐2D phases, to ≈500 nm for the 2D phase. The dynamic range of photoresponsivity (R) of PDs reflected the absorption trend, with the 2D perovskite being infrared blind. Graphene's high carrier mobility coupled with the perovskite's high absorbance resulted in an unprecedented high R of ≈107 A W−1 and specific detectivity of 9.77 × 1016 Jones under 42.25 nW cm−2 of 405 nm illumination for the predefined n = 2 film. This underscores the potential of the DJ phase quasi‐2D perovskite@graphene in realizing stable, sensitive, and spectrally tunable PDs.

Acceleration of radiative recombination for efficient perovskite LEDs

The increasing demands for more efficient and brighter thin-film light-emitting diodes (LEDs) in flat-panel display and solid-state lighting applications have promoted research into three-dimensional (3D) perovskites. These materials exhibit high charge mobilities and low quantum efficiency droop1–6, making them promising candidates for achieving efficient LEDs with enhanced brightness. To improve the efficiency of LEDs, it is crucial to minimize nonradiative recombination while promoting radiative recombination. Various passivation strategies have been used to reduce defect densities in 3D perovskite films, approaching levels close to those of single crystals3. However, the slow radiative (bimolecular) recombination has limited the photoluminescence quantum efficiencies (PLQEs) of 3D perovskites to less than 80% (refs. 1,3), resulting in external quantum efficiencies (EQEs) of LED devices of less than 25%. Here we present a dual-additive crystallization method that enables the formation of highly efficient 3D perovskites, achieving an exceptional PLQE of 96%. This approach promotes the formation of tetragonal FAPbI3 perovskite, known for its high exciton binding energy, which effectively accelerates the radiative recombination. As a result, we achieve perovskite LEDs with a record peak EQE of 32.0%, with the efficiency remaining greater than 30.0% even at a high current density of 100 mA cm−2. These findings provide valuable insights for advancing the development of high-efficiency and high-brightness perovskite LEDs.

Highly Oriented FAPbI3 via 2D Ruddlesden Popper Perovskite Template Growth

Abstract2D perovskites are demonstrated as the growth template for the modulation of phase transition and crystallization of formamidinium lead triiodide (FAPbI3). However, it is challenging to obtain highly oriented α‐FAPbI3 and regulate crystallization at the bottom of the FAPbI3 film. Here, a 2D (BA)2PbI4 layer with preferred orientation is introduced to perform as the bottom template for the quasi‐epitaxial growth of FAPbI3, which triggers the α‐FAPbI3 perovskite formation. Owing to the assembly of [PbI6]4− octahedral on the 2D template, the highly (100) oriented FAPbI3 perovskites from the bottom to the top are attained. At the optimum concentration, 2D perovskites gradually vanish due to the extrusion of BA+ cation from the template, which guarantees the charge transport at the bottom. Consequently, the strategy effectively promotes film quality and suppresses non‐radiative recombination. The efficiency of perovskite solar cells (PSCs) is promoted from 23.06% to 24.78%.