Perovskite Formation Research Articles

Ultrafast Photoexcitation Induced Passivation for Quasi-2D Perovskite Photodetectors.

Quasi-2D perovskites exhibit great potential in photodetectors due to their exceptional optoelectronic responsivity and stability, compared to their 3D counterparts. However, the defects are detrimental to the responsivity, response speed, and stability of perovskite photodetectors. Herein, an ultrafast photoexcitation-induced passivation technique is proposed to synergistically reduce the dimensionality at the surface and induce oxygen doping in the bulk, via tuning the photoexcitation intensity. At the optimal photoexcitation level, the excited electrons and holes generate stretching force on the Pb─I bonds at the interlayered [PbI6]-, resulting in low dimensional perovskite formation, and the absorptive oxygen is combined with I vacancies at the same time. These two induced processes synergistically boost the carrier transport and interface contact performance. The most outstanding device exhibits a fast response speed with rise/decay time of 201/627ns, with a peak responsivity/detectivity of 163 mA W-1/4.52 × 1010 Jones at 325nm and the enhanced cycling stability. This work suggests the possibility of a new passivation technique for high performance 2D perovskite optoelectronics.

Mitigating deactivation in dry methane reforming by lanthanum catalysts for enhanced hydrogen production: A review

Catalyst deactivation in dry methane reforming, resulting from coke accumulation and sintering, has long captivated academic interest due to its negative impact on catalytic performance and hindrance to industrial scalability. Thus, developing efficient catalysts capable of sustaining high reforming activity and stability is crucial. Lately, lanthanum (La) has gained popularity in catalysis for its ability to enhance performance and resist coking, owing to its great basicity, redox capabilities, and high oxygen storage capacity. As a result, diverse strategies for incorporating La into catalysts, including support, promoter, bimetallic combinations, and perovskite formation, have been extensively explored. Herein, this review delves into various advancements in lanthanum-based catalysts and their effectiveness in dry methane reforming while addressing catalyst deactivation and regeneration. Finally, the prospect of La-based catalysts in dry methane reforming is also emphasized in this review.

Fabrication and characterization of methylammonium lead iodide-based perovskite solar cells under ambient conditions

<p>This study investigated the fabrication and characterization of CH<sub>3</sub>NH<sub>3</sub>PbI<sub>3</sub> based perovskite solar cells (PSCs) using the one-step spin coating technique under ambient conditions, eliminating the need for expensive glovebox and thermal evaporation equipment. The perovskite layer was annealed at 65 °C for 30 seconds and 100 °C for 30 seconds, 1 and 2 minutes. The scanning electron microscope (SEM) images show a smooth and uniform surface coverage for the ETL and CH<sub>3</sub>NH<sub>3</sub>PbI<sub>3</sub> layers. SEM results also show an average grain size of 397 nm for CH<sub>3</sub>NH<sub>3</sub>PbI<sub>3</sub> and an average particle size of ~17 nm for TiO<sub>2</sub> was confirmed by transmission electron microscopy (TEM). X-ray diffraction (XRD) results confirmed the formation of tetragonal perovskite (CH<sub>3</sub>NH<sub>3</sub>PbI<sub>3</sub>) phase with high crystallinity with a crystallite size of 19.99 nm for the samples annealed for 30 seconds at 65 °C and 1 min at 100 °C. FTIR results also confirmed the presence of anatase TiO2 at wavenumber 438 cm<sup>-1</sup> and the formation of the adduct of Pb<sub>2</sub> with dimethyl sulfoxide (DMSO) and MAI is confirmed at 1,015 cm<sup>-1</sup> . From the Tauc plot the bandgap energy of TiO2 and Perovskite layers was determined to be 3.52 eV and 2.06 eV respectively. An open-circuit voltage was 0.9057 V and short circuit current density was 12.2185 mA/cm<sup>2</sup> with a fill factor of 48.05 and power conversion efficiency (PCE) of 5.199%.</p>

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.

Impedance spectroscopy investigation on the electrical response and optical characteristics of novel Sr2TiZrO6 double perovskite

This study centers on the synthesis and characterization of a novel double perovskite, termed Sr2TiZrO6 (STZO), which was synthesized using the conventional solid-state reaction method and subsequently calcined at 1000 °C for 12 h. X-ray diffraction (XRD) pattern refinement confirmed the formation of the tetragonal phase Sr2TiZrO6 (space group P4mm), while both XRD and scanning electron microscope (SEM) analyses revealed that the resulting STZO displaying spherical-like grains with nanometric diameters. Thermogravimetric analysis revealed a minor weight loss attributed to the emergence of the ZrO2 phase and the formation of the STZO double perovskite. The diffuse reflectance spectroscopy (DRS) results demonstrated strong UV-light absorption, with an optical absorption onset below 400 nm. The obtained band gap for direct transitions of the STZO sample is equal to 3.26 eV. The conductance and impedance study of the STZO sample are investigated. The present properties provide crucial insights to enhance comprehension of the STZO double perovskite material, which holds promise as a viable candidate for a range of applications, such as solar cells and photodiodes.

Pyridine substitution strategy for one-dimensional perovskite: Toward efficient and stable mixed-dimensional photovoltaics

Surface passivation via one-dimensional (1D) perovskite has emerged as a promising method to suppress trap states and enhance charge extraction and transportation, leading to improved efficiency and long-term stability. Ionic liquid engineering, characterized as environmental-green additive, has shown particular promise in this regard. Herein, we explore the influence of the electronegativity and dipole moment of two different ionic liquids, benzamidine hydrochloride (BZ) and 2-amidinopyridine hydrochloride (2AP), on the formation of 1D perovskite and the performance of resulting devices. An effective passivation 1D layer has been formed through post-treatment, resulting in nano-rod crystal modified morphology with effectively passivated defects at grain boundaries, enhanced hydrophobicity, prolonged charge carrier lifetime, tailored energy level, and decreased trap density. Notably, the perovskite film treated with 2AP exhibited superior performance due to its stronger interaction with 3D perovskite and better passivation ability on defects originating from the presence of a pyridine ring. As a result, the PSCs incorporating 2AP achieved a champion power conversion efficiency of 24.55 % and retain 90 % of their initial efficiency after storage for over 1000 h at room temperature under ∼ 50 % RH conditions without encapsulation. This study provides valuable insights for expanding the selection of ionic liquids applied in 1D perovskite-assisted surface passivation towards efficient and stable photovoltaics.

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%.

Oxygen evolution reaction kinetics and photoluminescence studies of zinc stannate (ZnSnO3/Zn2SnO4) nanoparticles synthesized via [formula omitted] mediated route

A groundbreaking method utilizing Aloebarbadensismiller gel to synthesize novel zinc stannate nanoparticles in two distinct phases, followed by calcination at 600 °C, has been developed. Structural, optical, and electrochemical analyses were meticulously conducted to explore the impact of phase variation. X-ray diffraction confirmed the formation of face-centered perovskite and inverse spinel cubic structures for ZnSnO3 and Zn2SnO4 nanoparticles respectively, with irregular sizes and shapes observed in both phases. Energy-dispersive X-ray spectroscopy confirmed their purity. Tauc’s plot revealed direct energy band gaps of 3.45 eV and 3.4 eV for ZnSnO3 and Zn2SnO4 respectively, with photoluminescence emission spectra displaying distinct peaks at 646 nm and 647 nm. The study identified higher defect levels in the inverse spinel structure. Notably, the synthesized nanoparticles exhibited promising characteristics for light-emitting diodes and display technology, with color-correlated temperatures (6810 and 6695 K) suggesting their potential application. Furthermore, the nanoparticles demonstrated remarkable performance in oxygen evolution reaction (OER) studies, with low overpotentials (η10) in the range of 269 mV and 273 mV along with a minimal Tafel slope of 76 mV dec−1 and stable electrochemical behavior over 45 h at a current density of 20 mA/cm2, indicating their efficacy as electrocatalysts. The current work unveils the novel synthesis of zinc stannate nanoparticles through an Aloebarbadensismiller gel, a method that stands out for its eco-friendly and cost-effective nature. We delve into uncharted territory by investigating these nanoparticles’ oxygen evolution reaction kinetics and photoluminescence properties, shedding light on their potential applications in energy conversion and sensing technologies. This pioneering study contributes to the understanding of zinc stannate nanoparticles’ behavior, paving the way for transformative advancements in various fields.

Equally Efficient Perovskite Solar Cells and Modules Fabricated via N-Ethyl-2-Pyrrolidone Optimized Vacuum-Flash.

Efficiency reduction in perovskite solar cells (PSCs) during the magnification procedure significantly hampers commercialization. Vacuum-flash (VF) has emerged as a promising method to fabricate PSCs with consistent efficiency across scales. However, the slower solvent removal rate of VF compared to the anti-solvent method leads to perovskite films with buried defects. Thus, this work employs low-toxic Lewis base ligand solvent N-ethyl-2-pyrrolidone (NEP) to improve the nucleation process of perovskite films. NEP, with a mechanism similar to that of N-methyl-2-pyrrolidone in FA-based perovskite formation, enhances the solvent removal speed owing to its lower coordination ability. Based on this strategy, p-i-n PSCs with an optimized interface attain a power conversion efficiency (PCE) of 24.19% on an area of 0.08 cm2. The same nucleation process enables perovskite solar modules (PSMs) to achieve a certified PCE of 23.28% on an aperture area of 22.96 cm2, with a high geometric fill factor of 97%, ensuring nearly identical active area PCE (24%) in PSMs as in PSCs. This strategy highlights the potential of NEP as a ligand solvent choice for the commercialization of PSCs.

Investigation of structural, morphological, dielectric, optical, and ferroelectric-energy storage properties of [(1-x) BCT-(x) BZT] electroceramics

Extensive research and advancements have been progressed by the vast potential of eco-friendly dielectric capacitors in high-level electronic elements and high-performance pulsed power systems thus far. Ferroelectric ceramic materials exhibiting relaxor properties and significant dielectric constants are prime candidates for attaining exceptional energy storage capabilities. Herein, a lead-free (1-x) Ba0.9Ca0.1TiO3–xBaZr0.15Ti0.85O3 (abbreviated as (1-x) BCT-xBZT) solid solution system has been synthesized via the conventional solid-state reaction technique, with varying levels of BZT doping. The X-ray diffraction study confirmed pure perovskite structure formation in the prepared ceramics, and the coexistence of orthorhombic (O) (space group- Amm2) and tetragonal (T) (space group-P4mm) phases has been detected through the Rietveld refinement technique at room temperature. Rietveld refinement data and associated analysis highlight the gradual shift of crystal symmetry from Amm2 to P4mm as the x content increases. Replacing BZT in Ca-modified BaTiO3 has led to significant enhancements in microstructural properties and an increase in the width of the optical band gap. This, in turn, enhances energy storage capabilities compared to pure BCT. Incorporating BZT into BCT has led to the evolution of relaxor ceramics, a crucial development for achieving elevated levels of recoverable energy storage density. In this study, the solid solution comprising 0.6BCT-0.4BZT exhibits distinct traits, including a diffuse phase transition, high breakdown strength, shallow dielectric loss (tanδ <0.007), and significantly high dielectric constant. Due to enhanced electrical characteristics, the 0.6BCT-0.4BZT possesses very high saturation polarization of ∼48 μCcm−2, a total energy density of 1.71 J/cm3, and a recoverable energy density of 1.1 J/cm3. In addition, the optimized ceramics demonstrate concurrent achievement of high-frequency stability (10–250 Hz), fatigue resistance (up to 104 cycles), and favorable temperature stability (20–160°C). This study showcased a potential material candidate suitable for energy storage devices functioning within low to medium-electric fields.

Development of Superior Nickel Oxide Layer for Boosted Hole‐Transport Performance in Perovskite Solar Cells

Although revolutionary power conversion efficiency progress has been realized for inverted perovskite solar cells (PSCs), the selection and optimization of the hole‐transporting materials (HTMs) are still crucial for fabricating high‐efficiency, stable, and low‐cost PSCs. Nickel oxide (NiOx) is widely used in the PSCs community for material design and modification. However, various NiOx synthesis processes lead to kinds of NiOx, and it is difficult to determine which NiOx is suitable for application in PSCs. Herein, two kinds of NiOx HTMs are synthesized using sol–gel processed and chemical‐calcination‐processed (CCP) routes for the preparation of PSCs. Based on the physical properties of two kinds of NiOx HTMs as well as the corresponding photovoltaic parameters of PSCs, it is demonstrated that superior NiOx HTMs is obtained by the CCP method with the following properties: high transmittance to ensure sufficient sunlight capture of perovskite, appropriate energy levels to promote hole extraction and transfer, high conductivity to support charge transfer, and a good wetting surface to boost perovskite spreading and film formation. Thus, in this study, the direction for the reasonable selection of HTMs is pointed out to prepare efficient PSCs.

Dual Defect Passivation at the Buried Interface for Printable Mesoscopic Perovskite Solar Cells with Reduced Open-Circuit Voltage Loss.

Numerous defects exist at the buried interface between the perovskite and adjacent electron transport layers in perovskite solar cells, resulting in severe non-radiative recombination and excessive open-circuit voltage (VOC) loss. Herein, a dual defect passivation strategy utilizing guanidine sulfate (GUA2SO4) as an interface modifier is first reported. On the one hand, the SO4 2- preferentially interacts with Pb-related defects, generating water-insoluble lead oxysalts complexes. Additionally, GUA+ diffuses into the perovskite and induces the formation of low-dimensional perovskite. These reactions effectively suppress trap states at the buried interface and perovskite boundaries in printable mesoscopic perovskite solar cells (p-MPSCs), thus increasing the carrier lifetime. Meanwhile, GUA2SO4 optimizes the interface energy band alignment, thus accelerating the charge extraction and transfer at the buried interface. This synergistic effect of trap passivation and interface energy band alignment modulation is strongly demonstrated by an increase in average VOC of 70mV and the power conversion efficiency improvement from 17.51% to 18.70%. This work provides a novel approach to efficiently improve the performance of p-MPSCs through dual-targeted defect passivation at the buried interface.

Phase-stable wide-bandgap perovskites enabled by suppressed ion migration

Wide-bandgap (>1.7 eV) perovskites suffer from severe light-induced phase segregation due to high bromine content, causing irreversible damage to devices stability. However, the strategies of suppressing photoinduced phase segregation and related mechanisms have not been fully disclosed. Here, we report a new passivation agent 4-aminotetrahydrothiopyran hydrochloride (4-ATpHCl) with multifunctional groups for the interface treatment of a 1.77-eV wide-bandgap perovskite film. 4-ATpH+ impeded halogen ion migration by anchoring on the perovskite surface, leading to the inhibition of phase segregation and thus the passivation of defects, which is ascribed to the interaction of 4-ATpH+ with perovskite and the formation of low-dimensional perovskites. Finally, the champion device achieved an efficiency of 19.32% with an open-circuit voltage (VOC) of 1.314 V and a fill factor of 83.32%. Moreover, 4-ATpHCl modified device exhibited significant improved stability as compared with control one. The target device maintained 80% of its initial efficiency after 519 h of maximum power output (MPP) tracking under 1 sun illumination, however, the control device showed a rapid decrease in efficiency after 267 h. Finally, an efficiency of 27.38% of the champion 4-terminal all-perovskite tandem solar cell was achieved by mechanically stacking this wide-bandgap top subcell with a 1.25-eV low-bandgap perovskite bottom subcell.

Lead-based paint detection using perovskite fluorescence and X-ray fluorescence

BackgroundIngestion of flakes of Pb-based paint by infants remains a global health hazard with life-long consequences. Pb-based paint was banned for residential use in the US and Western Europe decades ago but is still sold in many countries. This study evaluates the performance of a new kit for detecting exposed Pb-based paint relying on the formation of Pb-halide perovskite that fluoresces bright green under a UV flashlight after spraying a non-toxic reagent. ResultsTests with the Lumetallix kit were conducted in parallel with X-fluorescence and inductively-coupled plasma atomic emission analysis upon acid digestion using paint currently sold in Côte d'Ivoire and samples of older US paint. Comparison of the three different methods indicates a detection limit for the Lumetallix kit of approximately 500 mg kg−1 (ppm) Pb in paint, with a sensitivity of 95 % and selectivity of 94 % relative to that threshold (n = 76). This detection limit is an order of magnitude below the US definition of Pb-based paint of 0.5 % (5,000 ppm) Pb by weight. SignificanceBecause the kit is easy to use, exposed paint posing a risk could reliably be screened at scale by the general public. Any follow-up for confirmation and mitigation based on XRF measurements will need to consider that Pb-based paint covered with low-Pb paint will not respond to the kit but will be detected by XRF through the overpainted layer.

Value-added recycling of iron and titanium from bauxite residue (Red Mud) via a flux-free smelting separation process

With enriched iron and titanium elements, red mud produced by the lime-free Bayer process showing high recycling value. This work proposed a pre-reduction and flux-free smelting process to recycle Fe/Ti resources from this red mud. Considering the extraction of titanium from smelting slag, classical calcareous flux was abandoned to avoid the formation of refractory perovskite. Instead, the FeO generated by pre-reduction of red mud itself was creatively applied to regulate the subsequent smelting separation. The full melting temperature of slag can be reduced from > 1700℃ to 1450℃-1550℃, as the FeO content in slag reached 10-20 wt%. The transition from rutile to ferrouspseudobrookite contributed to this change. Since the pre-reduced sample was smelted at 1600℃ for 60 min, 93.60 wt% of the iron element in red mud can be recycled in the form of iron nugget with grade of 99.6 wt%. Titanium in red mud can be recycled as Ti-rich slag, with TiO2 content of 55.91 wt%, for titanium dioxide production. The FeO in slag also suppressed the side reactions (i.e., carbonization of titanium and iron, reduction of silicon) in smelting process, which improved slag fluidity and iron nugget purity. This technique also provides a new approach for the utilization of V-bearing titanomagnetite, ilmenite, and other similar resources.

Advancing Monolithic Perovskite/TOPCon Tandem Solar Cells by Customizing Industrial‐Level Micro‐Nano Structures

AbstractTexturing silicon solar cells with micro/nano‐structures is crucial for achieving outstanding optical performance in perovskite/silicon tandem solar cells (TSCs). However, ensuring excellent electrical properties remains a challenge due to reduced passivation quality of the bottom silicon sub‐cells and difficulties in perovskite formation on textured substrates. Here, an industrial‐level sub‐micron random pyramid (sMRP) structure on the front side of a tunnel oxide passivating contact (TOPCon) solar cell using a simple alkaline texturing process is presented, resulting in excellent optical and electrical properties. Through meticulous fabrication process tuning, uniform sMRP textures with a size of 0.6–0.8 µm are achieved, exhibiting low reflectance comparable to industrial‐level micron random pyramid (MRP) structures. Optimizing annealing temperatures of double‐sided TOPCon structures textured with front‐sided sMRP and rear‐sided MRP, yields high passivation quality, with a remarkable implied open‐circuit voltage (iVOC) of 713 mV. Furthermore, the sMRP‐textured surface facilitates the formation of a high‐quality perovskite film with larger grain sizes and fewer internal pinholes compared to the polished counterpart. Consequently, a proof‐of‐concept p‐i‐n typed perovskite/TOPCon TSC featuring sMRP textures obtains an outstanding efficiency of 28.67%, providing a promising approach for the commercial production of high‐efficiency perovskite/TOPCon TSCs.

Passivating Defects via Retarding the Reaction Rate of FAI and PbI2 Enables Stable Perovskite Solar Cells.

The two-step sequential deposition strategy has garnered widespread usage in the fabrication of high-performance perovskite solar cells based on FAPbI3. However, the rapid reaction between FAI and PbI2 during preparation often leads to incomplete reactions, reducing the device efficiency and stability. Herein, we introduced a multifunctional additive, 2-thiophenyl trifluoroacetone (TTA), into the FAI precursor. The incorporation of TTA has proven to be highly effective in slowing the reaction rate between FAI and PbI2, resulting in increased perovskite formation and improved efficiency and stability of the devices. TTA's CF3 groups interact with FAI via hydrogen bonding, effectively suppressing FA+ defects. The S and C═O groups share lone pair electrons with uncoordinated Pb2+, leading to a reduction in perovskite film defects and suppressing nonradiative recombination. Additionally, the CF3 groups impart hydrophobicity, protecting the perovskite film from moisture-induced erosion. As a result, the TTA-modified perovskite film achieves a Champion efficiency of 23.42% compared to the control's 21.52, with 20.58% efficiency for a 25 cm2 solar module. Remarkably, the unencapsulated Champion device retains 86% of its initial PCE after 1080 h under dark conditions (60 ± 5 °C, 35 ± 5% RH), indicating enhanced long-term stability. These findings offer a promising and cost-effective tactic for high-quality perovskite film fabrication.

Solution Processed Hybrid Lead Perovskite Films for White Light Emission and Lasing Applications

Abstract2D organic–inorganic hybrid lead halide perovskite films are fascinating optoelectronic materials for white‐light emission and lasing applications. Here, it is demonstrated that nano‐meter‐thick films of perovskites can be formed at room temperature using Langmuir–Schaefer (LS) deposition technique. In situ X‐ray measurements reveal a self‐assembly process of the 2D perovskite formation at the air–water interface. This formation process requires the presence of stearic acid monolayer on the water subphase having a solution of lead‐perovskite in dimethylformamide. Microscopy and X‐ray measurements of these nanofilms transferred onto substrates show crystalline phase formation that deviates from the known orthorhombic structure of the bulk crystals. The nanofilms exhibit novel broad optical emission with sharp band‐edge transition in temperature‐dependent photoluminescence studies. Also, their band‐edge emission is distinctly blue‐shifted compared to that of thicker 2D perovskite flakes prepared by the slow‐cooling chemical synthesis process. 2D flakes exhibit lasing that cannot be obtained in the LS nanofilms as their thicknesses are lower than the lasing wavelength prohibiting wave‐guide formation. The results show that the 2D single‐crystalline nature of the LS films and flakes are suitable materials to develop broad‐band white light emission across the entire visible range and to obtain lasing without external cavities, respectively.

Crystallization modulation and defect passivation in carbon-based perovskite solar cells using multifunctional group additive

Recently, carbon-based perovskite solar cells have attracted wide attention in academia and industry because of their simple preparation process, low cost, and adaptability to roll-to-roll industrial production. The combination of ternary perovskite composition and carbon electrode configuration is expected to meet the requirements of device performance and stability. However, low grain size, and high density of grain boundary and surface defect states result in serious non-radiative recombination, which is one of the main gaps between the carbon-based perovskite solar cells and metal-electrode-based devices. Based on the consideration of crystal tuning and defect passivation of ternary CsFAMA thin films, the additive molecule 5-(Difluoromethoxy)-2-mercapto-1H-benzimidazole (DMB) with multifunctional groups were introduced into the film. XRD show that the (100) and (200) crystal plane orientation growth directed by the DMB additive lead to the formation of the micro-sized perovskite. XPS suggests that DMB not only modulates the crystallization of the films but also exists at the grain boundaries, and realizes the passivation of undercoordinated Pb2+ defects and inhibits the generation of Pb0. The defect state density is significantly reduced, and the carrier lifetime is greatly improved. The possible mechanism for perovskite crystal growth as well as defect passivation based on Lewis acid-base coordination and hydrogen bond was also proposed. After the introduction of DMB, a power conversion efficiency of 14.40% was achieved, which was 13.4% higher than that of the control device. After nearly 1200 h of environmental stability test, the DMB modified device still retained 95% of the original efficiency. This work emphasizes the feasibility of simultaneously realizing the crystallization modulation and defect passivation of carbon-based perovskite solar cells using the additive with multifunctional groups, and provides a reference for the commercialization of carbon-based perovskite solar cells.

Crystal Growth Nucleation Induced by CsPb2Br5 2D for Efficient and Stable Perovskite Solar Cells

Crystallization is a crucial step in obtaining high‐quality perovskite films. A 2D seed‐induced method is proposed for fabricating perovskite solar cells (PSCs). CsPb2Br5 significantly reduces the formation energy of perovskite according to the density functional theory calculations. The creation of perovskites is facilitated by CsPb2Br5, which also helps to improve the conditions for perovskite formation. The creation of large perovskite particles is accelerated by using a 2D seed‐precursor solution, which also improves the performance of PbI2 thin films. However, excessive doping can cause dopants to precipitate on the smooth surface of PbI2 thin films, resulting in the formation of perovskite thin films with numerous cracks, ultimately reducing device efficiency. Through meticulous optimization, the perovskite thin film obtained from a precursor solution with 30% concentration identifies the longest charge lifetime. With a remarkable power conversion efficiency of 24.06% under one solar illumination, the champion gadget demonstrates extraordinary photovoltaic performance. These results offer important insights for the logical design and manufacture of perovskite materials and have the potential to significantly advance PSC technology.