Iodide Acid Research Articles

How Ammonium Valeric Acid Iodide Additive Can Lead to More Efficient and Stable Carbon‐Based Perovskite Solar Cells: Role of Microstructure and Interfaces?

As perovskite photovoltaic devices can now compete with silicon technology in terms of efficiency, many strategies are investigated to improve their stability. In particular, degradation reactions can be hindered by appropriate device encapsulation, device architecture, and perovskite formulation. Mesoporous device architectures with a carbon electrode offer a plausible solution for the future commercialization of perovskite solar cells. They represent a low‐cost and stable solution with high potential for large‐scale production. Several studies have already demonstrated the potential of the mixed 2D/3D ammonium valeric acid iodide‐based MAPbI3 formulation to increase the lifetime of pure MAPbI3. They can however not describe the mechanisms responsible for the lifetime improvement. Using a full set of characterization techniques in the initial state and as a function of time during damp‐heat aging, new insights into the performance and degradation mechanisms may be observed. With (5‐AVA)0.05MA0.95PbI3, the solar cells are very stable up to 3500 h and the degradation of performances essentially results from the loss of electrical contacts mainly located at the interfaces. In contrast, for the neat MAPbI3, a poor stability is evidenced (T50 = 500 h) and the loss in performance results from the degradation of the bulk perovskite layer itself.

Cross‐Linked Pseudopeptides via Pd‐Catalyzed Carbonylative Coupling of α‐Amino Acid Iodides with α‐Amino Acid Esters in the Presence of a CO Surrogate

AbstractWe report the synthesis of cross‐linked pseudopeptides through a palladium‐catalyzed carbonylative cross‐coupling reaction. The reaction involves the coupling of α‐amino acid iodides with α‐amino acid esters via in situ CO insertion to give pseudopeptides linked by the side chain of the electrophilic counterpart. The key features are the use of a sustainable in situ CO surrogate, simple non‐inert conditions, short reaction time, and broad substrate scope. Both amino acids and peptide iodides were utilized as coupling partners.

A test of the universality principle: The solubility of metal salts and oxides in isobutyric acid + water near its consolute point

A mixture of isobutyric acid + water has a critical point of solution at a composition of 38.8 mass % isobutyric acid and a temperature near 300 K. Under these conditions, the pH = 2, which makes the mixture a ready solvent for metal salts and basic/amphoteric oxides. Measurements of the temperature dependence of the solubility of a solid in the critical region of such a mixture can be used as a test of the Principle of Critical Point Universality. This inductive generalization, which is thought to govern all critical phenomena, predicts that there will be a critical effect in the solubility of a solid when at constant temperature and pressure the position of equilibrium is specified by no more than three fixed variables. We report herein a determination of the temperature dependence of the solubility of gallium (III) oxide in a mixture of isobutyric acid + water, and in a separate experiment the determination of the temperature dependence of the solubility of titanium dioxide in this solvent. In a third experiment, we report the effects of the critical point of this mixture on the simultaneous dissolution of calcium sulfate and barium sulfate. In each of these experiments, there are three fixed variables. We carry out a fourth experiment involving the solubility of solid lead (II) iodide in isobutyric acid + water doped with completely dissolved sodium sulfate. In this case, four variables are fixed. Independent of the chemical details, and consistent with the universality principle, we find a critical solubility effect in each of the first three experiments but none in the fourth.

Easily obtained iodine and silver-iodine doped chitosan for medical and other applications

The complex of polysaccharide chitosan with iodide acid was obtained and characterized. The possibility of obtaining iodine preparations in chitosan matrix with enhanced ability of chitosan to retain iodine is suggested. In this study to improve the stability of iodine, novel chitosan iodine complex was prepared by mixing chitosan with HI. Chitosan iodine complex was obtained as a solution, which can be treated to form bulk samples with open porosity and the enhanced ability to retain iodine. Silver-doped materials comprise insoluble silver iodide in amorphous or nanocrystalline form. The anti-bacterial as well as anti-fungal activity assessment of complexes of chitosan and iodine and chitosan and iodine with Ag has shown that chitosan iodide and chitosan iodide with Ag are more effective against fungi.

Influence of Halides on the Interactions of Ammonium Acids with Metal Halide Perovskites.

Additive engineering is a common strategy to improve the performance and stability of metal halide perovskite through the modulation of crystallization kinetics and passivation of surface defects. However, much of this work has lacked a systematic approach necessary to understand how the functionality and molecular structure of the additives influence perovskite performance and stability. This paper describes the inclusion of low concentrations of 5-aminovaleric acid (5-AVA) and its ammonium acid derivatives, 5-ammoniumvaleric acid iodide (5-AVAI) and 5-ammoniumvaleric acid chloride (5-AVACl), into the precursor inks for methylammonium lead triiodide (MAPbI3) perovskite and highlights the important role of halides in affecting the interactions of additives with perovskite and film properties. The film quality, as determined by X-ray diffraction (XRD) and photoluminescence (PL) spectrophotometry, is shown to improve with the inclusion of all additives, but an increase in annealing time from 5 to 30 min is necessary. We observe an increase in grain size and a decrease in film roughness with the incorporation of 5-AVAI and 5-AVACl with scanning electron microscopy (SEM) and atomic force microscopy (AFM). Critically, X-ray photoelectron spectroscopy (XPS) measurements and density functional theory (DFT) calculations show that 5-AVAI and 5-AVACl preferentially interact with MAPbI3 surfaces via the ammonium functional group, while 5-AVA will interact with either amino or carboxylic acid functional groups. Charge localization analysis shows the surprising result that HCl dissociates from 5-AVACl in vacuum, resulting in the decomposition of the ammonium acid to 5-AVA. We show that device repeatability is improved with the inclusion of all additives and that 5-AVACl increases the power conversion efficiency of devices from 17.61 ± 1.07 to 18.07 ± 0.42%. Finally, we show stability improvements for unencapsulated devices exposed to 50% relative humidity, with devices incorporating 5-AVAI and 5-AVACl exhibiting the greatest improvements.

Managing Interfacial Defects and Carriers by Synergistic Modulation of Functional Groups and Spatial Conformation for High-Performance Perovskite Photovoltaics Based on Vacuum Flash Method.

Interfacial nonradiative recombination loss is a huge barrier to advance the photovoltaic performance. Here, one effective interfacial defect and carrier dynamics management strategy by synergistic modulation of functional groups and spatial conformation of ammonium salt molecules is proposed. The surface treatment with 3-ammonium propionic acid iodide (3-APAI) does not form 2D perovskite passivation layer while the propylammonium ions and 5-aminopentanoic acid hydroiodide post-treatment lead to the formation of 2D perovskite passivation layers. Due to appropriate alkyl chain length, theoretical and experimental results manifest that COOH and NH3 + groups in 3-APAI molecules can form coordination bonding with undercoordinated Pb2+ and ionic bonding and hydrogen bonding with octahedron PbI6 4- , respectively, which makes both groups be simultaneously firmly anchored on the surface of perovskite films. This will strengthen defect passivation effect and improve interfacial carrier transport and transfer. The synergistic effect of functional groups and spatial conformation confers 3-APAI better defect passivation effect than 2D perovskite layers. The 3-APAI-modified device based on vacuum flash technology achieves an alluring peak efficiency of 24.72% (certified 23.68%), which is among highly efficient devices fabricated without antisolvents. Furthermore, the encapsulated 3-APAI-modified device degrades by less than 4% after 1400h of continuous one sun illumination.

Compositional engineering and surface passivation for carbon-based perovskite solar cells with superior thermal and moisture stability

The inherent stability of perovskite absorbers towards environmental factors is a major limitation towards commercializing perovskite solar cells (PSCs). In this regard, MaPbI3 (MAPI) is engineered to attain thermal stability by incorporating Guanidinium iodide (GuI) and moisture stability by surface passivation using 5- amino valeric acid iodide (5-AVAI). The surface passivation of Gu modified MAPI, hereafter termed as GUMAPI, exhibits a 2D/3D perovskite interface, which, facilitates perovskite to attain high moisture and temperature stability. Various concentrations of 5-AVAI are used as the surface passivator. The stability of the surface-modified Gu doped MAPI films is studied thoroughly using time-dependent water contact angle measurements, in-situ temperature-dependent XRD analysis, and XRD studies of aged perovskite films under ambient conditions. 1AV films exhibit excellent temperature (>150 °C) and ambient stability (>59 days) when compared with control perovskite films (GUMAPI). The stability and performance of these perovskite films in a carbon-PSCs (CPSCs) architecture are evaluated by studying the current-voltage characteristics and assessing the device performance at various intervals. The 1AV-based CPSCs exhibit performance surpassing the control (GUMAPI) devices. A 9.0% increment is observed in the 1AV-based CPSCs compared to the GUMAPI-based CPSCs with an efficiency of 13.2% and a T80 lifetime of 93.2% without encapsulation.

Amino Acid‐Based Low‐Dimensional Management for Enhanced Perovskite Solar Cells

It has been reported that an overlayer of lower dimensional perovskite can effectively improve the properties of 3D perovskite solar cells. Here, 4‐aminobutyric acid (C4I) and 6‐aminocaproic acid iodides (C6I) are introduced onto the surface of the perovskite layer, forming a low‐dimensional (LD) capping layer on the 3D perovskite films for high‐performance devices. It is found that C4I forms a 2D perovskite layer, while C6I forms a 1D perovskite layer on the 3D perovskite surface. By using the LD capping layers, the integrated perovskite films show passivated surface traps, reduced defect density, improved carrier lifetimes, and altered band alignment, leading to improved fill factor and open‐circuit voltage and, hence, significantly higher device efficiency. The devices with the C4I and C6I capping layers achieve solar cell efficiencies as high as 23.48% and 23.11%, respectively. In addition, bare devices with the C4I and C6I integration maintain 93.73% and 91.58%, respectively, of their initial efficiencies after exposure to the ambient atmosphere for 2000 h, demonstrating much better stability than the pristine 3D holding only 83.30% of its initial efficiency. It appears that this 2D capping is more suitable for enhancing 3D perovskite performance for general photoelectronic applications than the 1D capping.

Determination of Folic Acid in Multivitamin Preparations by Reversed Phase HPLC

A great variety of components in multivitamin preparations containing folic acid, and a variety of test methods and conditions of folic acid determination proposed by manufacturers, require alignment of test procedures for products with similar composition.The aim of the study was to compare the results of experimental verification of folic acid determination procedures which use reversed phase high-performance liquid chromatography (RP HPLC) with isocratic elution mode. Materials and methods: The Agilent 1260 Infinity II LC system with a diode array detector (280 nm), isocratic elution mode, C8- and C18-bonded silica gel chromatographic columns, model mixtures containing folic acid, cyanocobalamin, ferrous sulfate, and potassium iodide, were used in the study.Results: The lowest relative standard deviation of the folic acid peak area (RSD=0.09%), and the lowest asymmetry factor (As=1.04) for folic acid were observed for the model mixture “ferrous sulfate+folic acid+cyanocobalamin” and the following test conditions. Column: 250×4.0 mm, silica gel for chromatography, octylsilyl (C8), endcapped; mobile phase: methanol‒phosphate buffer (12:88), pH 6.6; column temperature: 25ºС. The study demonstrated the feasibility of using these conditions for determination of pteroic acid impurity with simultaneous precipitation of interfering ferrous ions, using ethylenediaminetetraacetic acid solution, pH 9.5, as a solvent.Conclusions: RP HPLC can be recommended as an optimal aligned test procedure for determination of folic acid in combination products. It is recommended to use a solution containing folic and pteroic acids for system suitability testing.

Exploring the Effect of Ammonium Iodide Salts Employed in Multication Perovskite Solar Cells with a Carbon Electrode.

Perovskite solar cells that use carbon (C) as a replacement of the typical metal electrodes, which are most commonly employed, have received growing interest over the past years, owing to their low cost, ease of fabrication and high stability under ambient conditions. Even though Power Conversion Efficiencies (PCEs) have increased over the years, there is still room for improvement, in order to compete with metal-based devices, which exceed 25% efficiency. With the scope of increasing the PCE of Carbon based Perovskite Solar Cells (C-PSCs), in this work we have employed a series of ammonium iodides (ammonium iodide, ethylammonium iodide, tetrabutyl ammonium iodide, phenethylammonium iodide and 5-ammonium valeric acid iodide) as additives in the multiple cation-mixed halide perovskite precursor solution. This has led to a significant increase in the PCE of the corresponding devices, by having a positive impact on the photocurrent values obtained, which exhibited an increase exceeding 20%, from 19.8 mA/cm2, for the reference perovskite, to 24 mA/cm2, for the additive-based perovskite. At the same time, the ammonium iodide salts were used in a post-treatment method. By passivating the defects, which provide charge recombination centers, an improved performance of the C-PSCs has been achieved, with enhanced FF values reaching 59%, which is a promising result for C-PSCs, and Voc values up to 850 mV. By combining the results of these parallel investigations, C-PSCs of the triple mesoscopic structure with a PCE exceeding 10% have been achieved, while the in-depth investigation of the effects of ammonium iodides in this PSC structure provide a fruitful insight towards the optimum exploitation of interface and bulk engineering, for high efficiency and stable C-PSCs, with a structure that is favorable for large area applications.

Assessment of Molecular Additives on the Lifetime of Carbon-Based Mesoporous Perovskite Solar Cells

Perovskite solar cells have progressed very steadily, reaching power conversion efficiencies (PCE) beyond 20% while also improving their lifetimes up to 10,000 h. A large number of cell architecture and materials for active, transporting and electrode layers have been used, either in blends or in nanostructured layers. In this article, a set of perovskite solar cells have been designed, fabricated and characterized with special focus on their lifetime extension. The inclusion of 5-amino-valeric acid iodide (5–AVAI) as interlayer in a methyl-amino lead-iodide (MAPI) perovskite solar cell has provided additional stability in cells with PCE > 10% and T80 = 550 h. Experiments for up to 1000 h with solar cells at maximum power point under continuous illumination with solar simulator have been carried out (1 kW/m2, AM1.5G, equivalent to more than six months of outdoor illumination in locations such as Southeast Spain, with an average irradiation of 1900 kWh/m2/year). The addition of molecular additives in the bulk active layer and ETL and carbon layers not only allows better carrier transport, but also increases the stability of the perovskite solar cell by reducing ion migration within the bulk MAPI and between the different layers. Engineered interfaces with ZrO2 between the TiO2 and carbon layers contribute to reducing degradation.

Effects of 5-Ammonium Valeric Acid Iodide as Additive on Methyl Ammonium Lead Iodide Perovskite Solar Cells.

During the past decade, the power conversion efficiency (PCE) of perovskite solar cells (PSCs) has risen rapidly, and it now approaches the record for single crystal silicon solar cells. However, these devices still suffer from a problem of stability. To improve PSC stability, two approaches have been notably developed: the use of additives and/or post-treatments that can strengthen perovskite structures and the use of a nontypical architecture where three mesoporous layers, including a porous carbon backcontact without hole transporting layer, are employed. This paper focuses on 5-ammonium valeric acid iodide (5-AVAI or AVA) as an additive in methylammonium lead iodide (MAPI). By combining scanning electron microscopy (SEM), X-ray diffraction (XRD), time-resolved photoluminescence (TRPL), current–voltage measurements, ideality factor determination, and in-depth electrical impedance spectroscopy (EIS) investigations on various layers stacks structures, we discriminated the effects of a mesoscopic scaffold and an AVA additive. The AVA additive was found to decrease the bulk defects in perovskite (PVK) and boost the PVK resistance to moisture. The triple mesoporous structure was detrimental for the defects, but it improved the stability against humidity. On standard architecture, the PCE is 16.9% with the AVA additive instead of 18.1% for the control. A high stability of TiO2/ZrO2/carbon/perovskite cells was found due to both AVA and the protection by the all-inorganic scaffold. These cells achieved a PCE of 14.4% in the present work.

Stabilizing Perovskite Solar Cells to IEC61215:2016 Standards with over 9,000-h Operational Tracking

<h2>Summary</h2> The stability of perovskite solar cells (PSCs) has been considered as the largest obstacle to their commercialization. Herein, we observed that the main failure mechanism for MAPbI₃ perovskite is the escape of methylammonium (MA) iodide at the grain boundaries in an open space or the reconstruction of crystal in a confined small space, as well as the irreversible long-distance ionic migration under the multiple actions of light, heat, and electrical bias. Strengthened with bifunctional organic molecular of 5-ammoniumvaleric acid (5-AVA) iodide at the grain boundaries, the MAPbI₃ crystal was localized in the nanoscale, and thus, the decomposition or reconstruction was inhibited and the ionic migration became reversible. As a result, we propose a reliable approach to make PSCs meet stability standards of IEC61215:2016 qualification tests. A printable PSC filled with (5-AVA)_XMA_1-XPbI₃ has been working for more than 9,000 h at a maximum power point of 55°C ± 5°C without obvious decay.

5-Ammonium Valeric Acid Iodide to Stabilize MAPbI3 via a Mixed-Cation Perovskite with Reduced Dimension.

5-Ammonium valeric acid iodide (AVAI) has been widely known as a stabilizer to enhance the stability of MAPbI3 perovskite, but its role and function is still under exploration. The typical 2D perovskites of AVA2PbI4 have been proposed as the capping layer for stabilization. Here, a novel AVA-MA mixed-cation perovskite of AVAMAPbI4 is found to show a more even and compact coverage than the typical 2D perovskite of AVA2PbI4. A simple post-treatment on MAPbI3 films by using AVAI isopropanol solution can fabricate such a mixed-cation 2D perovskite capping layer on the MAPbI3 sample. This AVAMAPbI4 capping layer effectively passivates surface defects of MAPbI3 perovskite films and reduces the charge-carrier recombination, enabling AVAI-MAPbI3 perovskite films to exhibit improved stability against thermal and moisture stress. Finally, the AVAI-MAPbI3-based perovskite solar cells also show an enhanced photovoltaic performance with a champion PCE up to 20.05% with enhanced stability.

Using Solvent Vapor Annealing for the Enhancement of the Stability and Efficiency of Monolithic Hole-conductor-free Perovskite Solar Cells

In the last few years, perovskite solar cells have attracted enormous interest in the photovoltaic community due to their low cost of materials, tunable band gap, excellent photovoltaic properties and easy process ability at low temperature. In this work, we fabricated hole-conductor-free carbon-based perovskite solar cells with the monolithic structure: glass/FTO/bl-TiO\(_{2}\)/(mp-TiO\(_{2}\)/mp-ZrO\(_{2}\)/mp-carbon) perovskite. The mixed 2D/3D perovskite precursor solution composed of PbI\(_{2}\), methylammonium iodide (MAI), and 5-ammoniumvaleric acid iodide (5-AVAI) was drop-casted through triple mesoporous TiO\(_{2}\)/ZrO\(_{2}\)/carbon electrode films. We found that the isopropyl alcohol (IPA) solvent vapor annealing strongly influenced on the growth of mixed 2D/3D perovskite on triple mesoscopic layers. It resulted in the better pore filling, better crystalline quality of perovskite layer, thus the improved stability and efficiency of perovskite solar cell was attributed to lower defect concentration and reduced recombination.

Carbon-based, novel triple cation mesoscopic perovskite solar cell fabricated entirely under ambient air conditions

In the past, various reports on Perovskite Solar Cells (PSCs) have presented significant results. However, due to stability issues, scale-up drawbacks and high fabrication costs, scientists turned their focus on PSCs with a simpler structure, based on carbon electrodes. In this work, we report a carbon-based PSC, embedding a novel, triple cation perovskite, created after combining Methylammonium Iodide (MAI), 5-Aminovaleric Acid Iodide (5-AVAI) and Lead(II) Iodide (PbI2) along with Phenethylammonium Iodide (PEAI) salt. In our Hole Transport Layer (HTL) free device, the perovskite was infiltrated through the conductive porous carbon cathode layer, which is deposited on top of compact/mesoporous TiO2 (c-TiO2/mp-TiO2) and mesoporous insulating ZrO2 (mp-ZrO2) layers, with all processes being carried out under ambient conditions and high relative humidity (40–60%). Finally, the perovskite films (5-AVA)x(MA)1-xPbI3 and (5-AVA)x(PEA)x(MA)1-xPbI3+x are optically/structurally characterized and the electrical performance of the corresponding devices is examined.

Improved performance and stability of hole-conductor-free mesoporous perovskite solar cell with new amino-acid iodide cations

Carbon-based and hole-transporting-material-free perovskite solar cells (PSCs) are a promising alternative structure for low-cost applicable method to their manufacturing. However, in this technology, the presence of 5-ammonium valeric acid iodide (5-AVAI) as co-cation to the commonly used MAPbI3 perovskite is necessary which promotes the crystal nucleation and growth within TiO2/ZrO2 mesoscopic oxide scaffold, while affects the contact of perovskite with hydrophobic carbon electrodes. Herein, we present the use of alternative and very low-cost amino acids with comparable and even better performance in some cases of as-used 5-AVAI. On that purpose, two common amino acids of dl-leucine and dl-alanine are used for the synthesis of their iodide derivatives also performed as co-cation with methyl ammonium iodide into the MAPbI3. The structural, optical, and electrical characteristics of the PSCs prepared with newly presented amino acids are examined in comparison with those obtained for (5-AVA)xMA1–xPbI3 perovskite as a reference. In the case of dl-leucine iodide-based perovskite, enhanced stability and performance over 5-AVAI was monitored to their PSCs for over 120 days referring to unsealed devices under 60% relative humidity.

Layered Ruddlesden–Popper Perovskites with Various Thicknesses for Stable Solid-State Solar Cells

The present research comes up with optimizing the layers thickness of a Ruddlesden–Popper perovskite with the general formula of (S0.97$${\text{S}}_{{0.03}}^{'}$$)2[Cs0.05(FA0.097MA0.03)0.95]n – 1Pbn(I0.97Br0.03)3n + 1 for efficient, stable solar cell applications. Such a triple-cation quasi-two-dimensional (2D) structure simultaneously contains two spacers, namely 5-ammonium valeric acid iodide (S) and tetra-n-octylammonium bromide (S'). Systematic studies showed that morphology, crystal structure, optical properties, photovoltaic performance, and internal resistances of this compound depended upon the value of the n integer. Field emission scanning electron microscopy set forth that the deposited films were composed of various morphologies depending on the n value. An increase in the n value resulted in improving the light absorption, reducing the band gap energy, and blue-shifting the photoluminescence peak. So as to fabricate solar cells, CuInS2 nanoparticles were employed as a novel hole-transporting material. The device based on the film having n = 4 value showed the highest power conversion efficiency of 10.2%. Electrochemical impedance spectroscopy demonstrated that the improved performance of this cell was mainly thanks to its low series resistance (11.68 Ω), high charge recombination resistance (922.35 Ω), and long electron lifetime (8.05 μs) as compared to all the fabricated cells. Moreover, this cell displayed a maximum external quantum efficiency of 82% among all the devices. The un-encapsulated solar cells showed that the output reduction directly depended on the n value so that the cell based on the n = 4 reached 82% of its initial power over 2500 h in ambient conditions.

Investigating the Superoxide Formation and Stability in Mesoporous Carbon Perovskite Solar Cells with an Aminovaleric Acid Additive

AbstractPerovskite solar cells have attracted a great deal of attention thanks to their high efficiency, ease of manufacturing, and potential low cost. However, the stability of these devices is considered their main drawback and needs to be addressed. Mesoporous carbon perovskite solar cells (m‐CPSC), consisting of three mesoporous layers (TiO2/ZrO2/C) infiltrated with CH3NH3PbI3 (MAPI) perovskite, have presented excellent lifetimes of more than 10 000 h when the additive NH2(CH2)4CO2HI (5‐ aminovaleric acid iodide; 5‐AVAI) is used to modify the perovskite structure. Yet, the role of 5‐AVAI in enhancing the stability has yet to be determined. Here, superoxide‐mediated degradation of MAPI m‐CPSC with and without the 5‐AVAI additive is studied using the fluorescence probe dihydroethidium for superoxide detection. In situ X‐ray diffractometry shows that aminovaleric acid methylammonium lead iodide (AVA‐MAPI) perovskite infiltrated in mesoporous layers presents higher stability in an ambient environment under illumination, evidenced by a slower decrease of the MAPI/PbI2 peak ratio. Superoxide yield measurements demonstrate that AVA‐MAPI generates more superoxide than regular MAPI when deposited on glass but generates significantly less when infiltrated in mesoporous layers. It is believed that superoxide formation in m‐CPSC is dependent on a combination of competitive factors including oxygen diffusion, sample morphology, grain size, and defect concentration.

Development of a triple-cation Ruddlesden–Popper perovskite structure with various morphologies for solar cell applications

The present research sheds new light on the development of a triple-cation quasi-two-dimensional (2D) perovskite family with the general formula of (S1−xS′x)2[Cs0.05(FA1−xMAx)0.95]3Pb4(I1−xBrx)13, in which two spacers, namely 5-ammonium valeric acid iodide (S) and tetra-n-octylammonium bromide (S′) were simultaneously incorporated. Morphology, crystal structure, optical properties, photovoltaic performance, and internal resistances of such compound were systemically studied in comparison with an analogous single-cation 2D counterpart (i.e. (S)2(FA)3Pb4I13) as a reference. X-ray diffraction set forth that the films deposited based upon these compounds had a 2D perovskite crystal structure owing to the pronounced (0 k 0) peak series at low angles. Field emission scanning electron microscopy propounded that the layered ultrathin 2D structures were stacked up to produce various 3D solids such as particles, flowers, needles, sheets, blades, and cubes, depending on the spacers atomic ratios (i.e. x = S′/S + S′) in the range of 0–0.05. Moreover, the photoluminescence spectra of the films exhibited that the triple-cation perovskites had lower bandgap of around 1.68 eV compared to the reference film (ca., 1.74 eV), confirming the formation of 2D perovskites. The device fabricated based on 97 at% S and 3 at% S′ (i.e. x = 0.03) showed the highest power conversion efficiency of 10.2% due mainly to its low series resistance (11.7 Ω), high charge recombination resistance (922.4 Ω), and long electron lifetime (8.0 µs) among the fabricated cells. The un-encapsulated x = 0.03 cell displayed a maximum external quantum efficiency of 82% and lost just 18% of its initial efficiency after 2500 h in ambient conditions.