Methylammonium Iodide Research Articles

On the Synergistic Interplay Between Annealing Temperature and Time and Additive Concentration for Efficient and Stable FAPbI3 Perovskite Solar Cells

Formamidinium-based lead triiodide perovskite (FAPI) is the workhorse candidate for highly efficient perovskite solar cells owing to its ideal bandgap and phase purity. An essential condition to that is the formation of a pure α-black phase, commonly triggered by external additives such as methylammonium chloride (MACl). This results in the suppression of unwanted crystallization phases and defect reduction. However, there is no consensus on the exact experimental conditions (i.e. annealing time, temperature and concentration) for processing of the additives neither a defined relationship between them nor the resulting film morphology, leading to scattered knowledge on it and lack of thin film reproducibility. Here, we provide a systematic investigation on the simultaneous effect of MACl concentration, annealing time, and annealing temperature on the FAPI crystallization, and ultimately FAPI perovskite solar cell efficiency and stability. Finally, the optimized combination of such parameters, based on tests with 230 devices, leads to the realization of 22.7% efficient inverted FAPI perovskite solar cells with enhanced stability.

A facile approach for fabricating efficient and stable perovskite solar cells.

Perovskite solar cells (PSCs) with high power conversion efficiencies (PCEs) can be produced using a variety of methods, such as different fabrication methods, device layout modification, and component and interface engineering. The efficiency of a perovskite solar cell is largely dependent on the overall quality of the perovskite thin-film in every scenario. The utilization of spin-coating followed by the antisolvent pouring (ASP) method is prevalent in nearly all fabrication techniques to achieve superior perovskite thin-films. Nevertheless, there are a few guidelines that must be followed precisely when using the ASP approach, including the antisolvent amount, duration, and area for dropping. The aforementioned challenging and necessary strategies frequently result in perovskite thin-films with pinholes, tiny grains, and broad grain boundaries, which impair the performance of PSCs. Therefore, the implementation of a straightforward approach that does not require the use of such complex ASP steps is crucial. Here, we employ a simple process that involves the hot-dipping of lead iodide (PbI2) thin-films in a hot solution of methylammonium iodide (MAI) and formamidinium iodide (FAI) in isopropanol (IPA) to produce high-quality perovskite thin-films. As the time required for the desired perovskite to crystallize is critical, we carefully examined various hot-dipping process times, such as 10 seconds, 20 seconds, 30 seconds, and 40 seconds. These time intervals yielded thin-films, which were named PSK-10, PSK-20, PSK-30, and PSK-40, respectively. Morphological and optoelectronic characterization demonstrated the high quality of the perovskite thin-films obtained through dipping PbI2 for 30 seconds. Consequently, the PSK-30-based PSCs produced higher PCEs of up to 21.52% compared to those of the ASP-based devices (20.79%). Furthermore, the unsealed PSCs prepared with PSK-30 and ASP were assessed for 252 hours at 25 °C and 40-45% relative humidity in order to determine their operational stability. The ASP-based device showed poor stability, retaining only 10% of its original PCE, whereas the PSK-30-based device retained 70% of its initial PCE. These results offer a new and viable approach for producing highly efficient and stable PSCs.

In Situ Potentiometric Monitoring of Nitrate Removal from Aqueous Solution by Activated Carbon and Ion Exchange Resin.

A nitrate selective electrode was used for real-time in situ potentiometric monitoring of a batch nitrate removal process using activated carbon and ion exchange resin. A plasticized polymeric membrane consisting of polyvinyl chloride, 2-nitrophenyl octyl ether and tridodecyl methyl ammonium chloride was incorporated into an ion-selective electrode body. First, the dynamic potential response of the electrode to nitrate was investigated. Two commercial activated carbons with different physical properties were then tested. Nitrate removal with these carbons was monitored potentiometrically using several nitrate concentrations. The extreme turbidity of the solutions was not a drawback during potentiometric monitoring of the process, which is a clear advantage over other methods such as optical monitoring. The potential versus time recordings were converted into nitrate concentration versus time plots, which were evaluated with different adsorption kinetic models. A pseudo-second order kinetic model for nitrate adsorption on both activated carbons was found to fit the experimental data very well. The values of the kinetic parameters were very different between the two activated carbons. The proposed methodology was also satisfactorily applied to the study of nitrate removal by an ion exchange resin. In this case, the experimental results clearly follow a pseudo-first order kinetic model. Potential applications of the proposed methodology for monitoring nitrate removal in real water samples are discussed.

Novel ethylbenzyl and hydroxyethyl quaternary ammonium collectors for co-reverse flotation desilication and impurity removal from phosphogypsum: Flotation performance and mechanism

In the reverse flotation process for desilication and impurity removal from phosphogypsum (PG), quaternary ammonium salts are commonly used as cationic collectors, but their selectivity and stability under strongly acidic conditions are limited. In this study, for the first time, dodecyl-dimethyl-ethyl benzyl ammonium chloride (DDEA) and dodecyl-bis(2-hydroxyethyl)-methyl ammonium chloride (2HEAC-12), were used as collectors for the PG co-reverse flotation desilication and impurity removal. Flotation experiments show that both DDEA and 2HEAC-12 collectors exhibit good desilication and impurity removal performance for PG, whereas DDEA shows superior selectivity for quartz than that of 2HEAC-12. When DDEA and 2HEAC-12 were used as collectors, the purity of dihydrate gypsum in obtained PG concentrates was 94.88% and 93.47%, respectively, meeting the first-grade standard for PG used as a building material (GB/T 23456–2018). Adsorption experiments indicate that the adsorption of both collectors on quartz and dihydrate gypsum follows the Langmuir model, suggesting monolayer physical adsorption. Both collectors exhibit a higher selectivity for quartz than dihydrate gypsum. The adsorption process was mainly accomplished by electrostatic interactions and hydrogen bonds. The adsorption process was mainly accomplished by electrostatic interactions and hydrogen bonds. This work provides a viable strategy for developing collectors for PG co-reverse flotation efficient desilication and impurity removal.

Multi-layered quasi-2D perovskite based triboelectric nanogenerator

Inorganic-organic perovskites are considered as one of the emerging candidates as a tribopositive material in triboelectric nanogenerators (TENG) owing to their unique functionalities. Among them, quasi-two-dimensional (quasi-2D) perovskites are promising materials for TENG due to layered nature, excellent environmental and chemical stability, tunability, and excellent electrical properties. Herein, we investigate the performance of TENG based on multiple series of perovskite layers using simple solution processing technique. The dimensionality of the perovskite layers is attained by changing the stoichiometric ratios of phenylethylammonium iodide (PEAI), lead iodide (PbI2), methylammonium iodide (MAI). The quasi-2D based TENG generates the maximum output electrical performance with a voltage of 306 V, current of 4.71 µA, and maximum power density of 3.48 µW/cm2 at the optimum value of (<n> = 5) due to the higher concentration of C–N and N–H groups. Moreover, the fabricated device shows stable performance for 12,000 cycles. The TENG device is further utilized to charge the various commercially available capacitors, for lightning of light-emitting diodes (LEDs), and to power up low-power electronic devices. These results demonstrate the effect of the dimensionality of perovskites on the output performance of the TENG for use in next-generation energy harnessing.

Synergistic effect of ionic liquid and methylammonium chloride in crystallization of hybrid haloplumbate for perovskite solar cells

The synergistic effect of ionic liquid 1-(2-hydroxyethyl)-3-methyl-1H-imidazol-3-ium cinnamate and methylammonium chloride (MACl) on the functional properties of mixed hybrid perovskites was discovered for the first time, which leads to a notable improvement in the quality of perovskite films and the photothermal stability of perovskite solar cells compared to reference devices.

Quartz crystal microbalance analysis of effects of surfactants on dissolution kinetics of poly(4-hydroxystyrene) partially protected by t-butoxycarbonyl group

Abstract Surfactants comprise water-repellent and water-attracting moieties and have been used to improve the lithographic performance of resist materials. However, the effects of surfactants on the dissolution kinetics of these materials are still unclear. In this study, the effects of surfactants on the dissolution kinetics of partially-protected poly(4-hydroxystyrene) (PHS) in 0.26 N tetramethylammonium hydroxide aqueous solution was investigated using a quartz crystal microbalance method. Anionic (sodium n-octanonate, sodium 1-hexanesulfonate, n-dodecylbenzenesulfonic acid, and sodium n-dodecyl sulfate), cationic (methylamine hydrochloride, dodecyltrimethylammonium chloride, and 30% ammonium lauryl sulfate solution), nonionic (sorbitan monooleate, polyoxyethylene(23)lauryl ether, and polyoxyethylene(10)hydrogenated castor oil), and amphoteric (35% lauryl dimethylaminoacetic acid solution) surfactants were examined. The surfactant significantly affected the dissolution kinetics of the PHS films. The surfactant effects were significantly reduced by protecting the hydroxyl groups of PHS. The effect of the surfactant on the dissolution kinetics depended on the surfactant rather than on the surfactant type.

Optimizing Formalin Detection in Fish Using QCM Sensors with TOMAC Membrane Coatings for Product Quality Monitoring

&lt;span lang="EN-AU"&gt;Detection of formalin in fishery products is a significant concern in the food industry to ensure consumer safety. This study compared the performance of Quartz Crystal Microbalance (QCM) sensors without a membrane and with a Trioctyl methyl ammonium Chloride (TOMAC) membrane coating in detecting formalin in fish samples. The research findings indicate that QCM without a membrane for formalin samples has a lower detection limit of 150 ppm and an upper detection limit of 350 ppm with a sensitivity of 2194.171 Hz/ppm. On the other hand, QCM with a TOMAC membrane coating has a lower detection limit of 400 ppm and an upper detection limit of 550 ppm with a sensitivity of 842.7551 Hz/ppm. Meanwhile, QCM without a membrane for formalin in fish samples has a lower detection limit of 450 ppm and an upper detection limit of 650 ppm with a sensitivity of 15386.38 Hz/ppm. At the same time, QCM with a TOMAC membrane coating for formalin in fish samples has a lower detection limit of 350 ppm and an upper detection limit of 500 ppm with a sensitivity of 23108.9 Hz/ppm. Response time analysis shows that both sensors reach a steady state condition after 12 seconds. This study highlights the importance of selecting appropriate sensors for detecting formalin in fishery products, considering detection limits, sensitivity, and response time as crucial criteria. Thus, these findings can guide the fisheries industry in choosing effective and accurate formalin detection technology.&lt;/span&gt;

Tuning Perovskite Crystal Growth Dynamics Using Additives on Textured Silicon Substrates

Double‐sided textured silicon solar cells with micrometer‐sized pyramid structure are used as bottom cells in monolithic tandem structures to decrease reflection losses. As top cell material, frequently perovskites are used. In this work, various additives are investigated to enhance the perovskite absorber quality, as a top cell fabricated using the hybrid route. In the context of the hybrid route, it is found that urea or methylammonium chloride (MACl) can effectively increase the grain size and improve the absorber quality, while formamidinium chloride (FACl) cannot. With urea, the crystallization can be tuned without leaving any voids in the film (unlike MACl). However, when annealed at a high annealing temperature, the excessive crystal growth with urea causes non‐conformal coating and high defect density. By adjusting the annealing conditions and additive concentration, the crystal growth of the perovskite top cell on the micrometer‐sized silicon pyramids can be fine‐tuned, ensuring that the perovskite layer conformally coated the pyramids. The use of additives not only improves crystallization but also enhances the conversion of the inorganics, particularly at the hole transport layer (HTL) interface. Moreover, this work contributes to a better understanding of perovskite crystallization dynamics and how to control it, especially on textured substrates.

Camphorsulfonic‐Salified Chitosan Allowing MACl‐Free Stabilization of Pure FAPbI3 α‐Phase via Gravure Printing in Ambient Air

Metal–halide perovskites have gained extreme interest in the photovoltaic field with formamidinium lead iodide (FAPbI3) currently being one of the best‐performing materials for single‐junction solar cells. Despite the outstanding record efficiencies, there are still several major issues hindering the large‐scale fabrication of perovskite solar cells. The vulnerability to environmental agents along with the need of controlled atmosphere and crystallization aids for the perovskite film deposition represents the major roadblocks. This is particularly true for FAPbI3 for which the thermodynamically stable phase at room temperature is photovoltaically inactive δ‐phase. To address those challenges, herein, a camphorsulfonic‐salified chitosan is specifically designed with the aid of DTF calculations to strongly interact with the perovskite and, as a result, improve the morphology and optoelectronic quality of the FAPbI3. Thanks to the numerous interactions and then the modulation of the solution viscosity, FAPbI3 devices are fabricated by gravure printing deposition without either antisolvent bath or inclusion of methylammonium chloride (MACl) as additive. The gravure‐printed devices with the chitosan feature an enhanced efficiency and stability in air, retaining 80% of the original efficiency after 1200 h in ambient air without any encapsulation.

In Situ Crystal Growth and Fusing-Confined Engineering of Quasi-Monocrystalline Perovskite Thick Junctions for X-ray Detection and Imaging.

Metal halide perovskites exhibit great promise for utilization in X-ray detection owing to their excellent optoelectronic properties and high X-ray attenuation capabilities. However, fabricating large-area thick films for high-performance perovskite X-ray detection remains challenging. This study develops an in situ crystal growth and fusing-confined approach to prepare high-quality, large-scale perovskite quasi-monocrystalline thick junctions. The perovskite crystals are grown in situ using a highly concentrated perovskite colloidal solution in 2-methoxyethanol. Introducing methylammonium chloride enhances grain reorganization during in situ growth and fusing-confined processes, effectively reducing grain boundaries and surface defects. This allows for the preparation of quasi-monocrystalline thick junctions of large grains (>100 μm) with high crystallinity, uniform orientation, and vertical penetration across the film thickness. Additionally, the carrier mobility and lifetime of the thick junctions are significantly enhanced. The optimized MAPbI3 detectors demonstrate an X-ray sensitivity of 2.6 × 104 μC Gyair-1 cm-2 and an exceptionally low detection limit of 1 nGyair s-1. Furthermore, inspired by a honeycomb structure, these detectors realize X-ray imaging in 64 × 64 pixels through a pixelated separation design, effectively reducing the charge-sharing effect. This study offers valuable insights into the preparation of large-scale perovskite quasi-monocrystalline thick junctions for highly sensitive X-ray detection and imaging applications.

Loading Precursors into Self‐Assembling Contacts for Improved Performance and Process Control in Evaporated Perovskite Solar Cells

Organo‐lead‐halide perovskites are promising materials for solar cell applications with efficiencies now exceeding 26% for single junction, and over 33% for silicon tandem devices. Evaporation has proven viable for industrial scale‐up but presents challenges for perovskite materials. Perovskite precursor is introduced into self‐assembling MeO‐2PACz hole transport layers for application to 4 source perovskite coevaporation. This allows precursors that can be difficult to add via evaporation, like methylammonium chloride. These precursor molecules influence growth during evaporation, film behavior during annealing as measured by photoluminescence, and aid the conversion to perovskite as shown by X‐Ray diffraction. Devices have improved power conversion efficiency and stability compared to a control sample within the same evaporation. The best cells reach ≈21% efficiency and comparable performing ≈20% cells maintain their original efficiency after 1000 h of maximum power tracking at 25 °C. This process provides significant process flexibility for perovskite evaporation and requires no additional steps.

High-efficiency and thermally stable FACsPbI3 perovskite photovoltaics.

α-FA1-xCsxPbI3 is a promising absorbent material for efficient and stable perovskite solar cells (PSCs)1,2. However, the most efficient α-FA1-xCsxPbI3 PSCs require the inclusion of the additive methylammonium chloride3,4, which generates volatile organic residues (methylammonium) that limit device stability at elevated temperatures5. Previously, the highest certified power-conversion efficiency of α-FA1-xCsxPbI3 PSCs without methylammonium chloride was only approximately 24% (refs. 6,7), and these PSCs have yet to exhibit any stability advantages. Here we identify interfacial contact loss caused by the accumulation of Cs+ in conventional α-FA1-xCsxPbI3 PSCs, which deteriorates device performance and stability. Through in situ grazing-incidence wide-angle X-ray scattering analysis and density functional theory calculations, we demonstrate an intermediate-phase-assisted crystallization pathway enabled by acetate surface coordination to fabricate high-quality α-FA1-xCsxPbI3 films, without using the methylammonium additive. We herein report a certified stabilized power output efficiency of 25.94% and a reverse-scanning power-conversion efficiency of 26.64% for α-FA1-xCsxPbI3 PSCs. Moreover, the devices exhibited negligible contact losses and enhanced operational stability. They retained over 95% of their initial power-conversion efficiency after operating for over 2,000 h at the maximum power point under 1 sun, 85 °C and 60% relative humidity (ISOS-L-3).

Colloidal Quasi-2D Methylammonium Lead Bromide Perovskite Nanostructures with Tunable Shape and High Chemical Stability.

Control over the lateral dimensions of colloidal nanostructures is a complex task which requires a deep understanding of the formation mechanism and reactivity in the corresponding systems. As a result, it provides a well-founded insight to the physical and chemical properties of these materials. In this work, the preparation of quasi-2D methylammonium lead bromide nanostripes and discuss the influence of some specific parameters on the morphology and stability of this material is demonstrated. The variation in the amount of the main ligand dodecylamine gives a large range of structures beginning with 3D brick-like particles at low concentrations, nanostripes at elevated and ultimately nanosheets at large concentrations. The amount of the co-ligand trioctylphosphine can alter the width of the nanostripe shape to a certain degree. The thickness can be adjusted by the amount of the second precursor methylammonium bromide. Additionally, insights are given for the suggested formation mechanism of these anisotropic structures as well as for stability against moisture at ambient conditions in comparison with differently synthesized nanosheet samples.

Polycrystalline methylammonium-lead bromide perovskite films for photonic metasurfaces

Polycrystalline films of organo-inorganic perovskite semiconductors are promising as a foundation for creating functional optical metasurfaces. The requirements for film structural perfection, thickness uniformity, and defect-free characteristics are much more stringent compared to perovskite films for photovoltaics. This work presents the results of searching for optimal conditions for one-step synthesis of lead methylammonium bromide films using centrifugation, and describes the successful fabrication of subwavelength optical gratings from these films through focused ion beam processing. The measured spectra of light transmission through the gratings demonstrated their excellent optical quality and confirmed the possibility of creating semiconductor photon metasurfaces with submicrometer periodicity and high-Q dielectric resonances.

Unified Crystal Phase Control with MACl for Inducing Single-Crystal-Like Perovskite Thin Films in High-Pressure Fusion Toward High Efficiency Perovskite Solar Cell Modules.

Perovskite solar cells, recognized for their high photovoltaic conversion efficiency (PCE), cost-effectiveness, and simple fabrication, face challenges in PCE improvement due to structural defects in polycrystalline films. This study introduces a novel fabrication method for perovskite films using methylammonium chloride (MACl) to align grain orientation uniformly, followed by a high-pressure process to merge these grains into a texture resembling single-crystal perovskite. Employing advanced visual fluorescence microscopy, charge dynamics in these films are analyzed, uncovering the significant impact of grain boundaries on photo-generated charge transport within perovskite crystals. A key discovery is that optimal charge transport efficiency and speed occur in grain centers when the grain size exceeds 10µm, challenging the traditional view that efficiency peaks when grain size surpasses film thickness to form a monolayer. Additionally, the presence of large-sized grains enhances ion activation energy, reducing ion migration under light and improving resistance to photo-induced degradation. In application, a perovskite solar cell module with large grains achieve a PCE of 22.45%, maintaining performance with no significant degradation under continuous white LED light at 100 mA cm-2 for over 1000h. This study offers a new approach to perovskite film fabrication and insights into optimizing perovskite solar cell modules.

Systematic anode engineering enabling universal efficiency improvements in organic solar cells

Anode modification and optimization is crucial towards improving performance of organic solar cells (OSCs). PEDOT:PSS is the most common choice as a hole transport layer (HTL) material, but suffers from issues including low conductivity. In this work, three alkyl amine derivatives - methylamine hydrochloride (MA), ethylamine hydrochloride (EA) and propylamine hydrochloride (PA) are doped into the commercially available Al 4083 PEDOT:PSS to form PEDOT:PSS-MA, PEDOT:PSS-EA and PEDOT:PSS-PA, as modified HTLs. All these modified HTLs exhibit improved chemical and electrical properties including work functions (WF), conductivities and charge carrier motilities. The alkyl amine doping shows compatibility in both Small Molecular Acceptors and All-Polymer OSCs. With PEDOT:PSS-MA demonstrates a highest PCE of 18.49 % compared to the 17.84 % of OSC devices prepared with pristine PEDOT:PSS with the PM6:L8-BO system, while PM6:PY-IT all-polymer OSCs improve PCE from 14.53 % to 15.22 %. AFM characterizations reveal that the introduction of the dopants have smoothened the surface morphology of spin-coated HTL films, which contributes towards more efficient charge extraction. In summary, this study not only presents a method of improving OSC efficiencies, but also provides insight and further possible directions towards anode optimization of OSCs.

Overcoming Microstructural Defects at the Buried Interface of Formamidinium-Based Perovskite Solar Cells.

Since the advent of formamidinium (FA)-based perovskite photovoltaics (PVs), significant performance enhancements have been achieved. However, a critical challenge persists: the propensity for void formation in the perovskite film at the buried perovskite-interlayer interface has a deleterious effect on device performance. With most emerging perovskite PVs adopting the p-i-n architecture, the specific challenge lies at the perovskite-hole transport layer (HTL) interface, with previous strategies to overcome this limitation being limited to specific perovskite-HTL combinations; thus, the lack of universal approaches represents a bottleneck. Here, we present a novel strategy that overcomes the formation of such voids (microstructural defects) through a film treatment with methylammonium chloride (MACl). Specifically, our work introduces MACl via a sequential deposition method, having a profound impact on the microstructural defect density at the critical buried interface. Our technique is independent of both the HTL and the perovskite film thickness, highlighting the universal nature of this approach. By employing device photoluminescence measurements and conductive atomic force microscopy, we reveal that when present, such voids impede charge extraction, thereby diminishing device short-circuit current. Through comprehensive steady-state and transient photoluminescence spectroscopy analysis, we demonstrate that by implementing our MACl treatment to remedy these voids, devices with reduced defect states, suppressed nonradiative recombination, and extended carrier lifetimes of up to 2.3 μs can be prepared. Furthermore, our novel treatment reduces the stringent constraints around antisolvent choice and dripping time, significantly extending the processing window for the perovskite absorber layer and offering significantly greater flexibility for device fabrication.

Controlled Crystallization and Enhanced Performance of γ-CsPbI3 Perovskite Through Methylammonium Iodide-Assisted Coevaporation.

Cesium lead triiodide (CsPbI3) perovskites have garnered significant attention owing to their suitable bandgap for tandem silicon substrates and excellent chemical stability. However, γ-CsPbI3 prepared via low-temperature co-evaporation is limited by a narrow black phase processing window and random crystal orientation, hindering its optoelectronic performance and industrial applications. This study introduced trace amounts of methylammonium iodide (MAI) into the co-evaporation system, enhancing the crystallization process, promoting columnar grain growth, and stabilizing the γ-phase perovskite, resulting in films with improved structural integrity and reduced defect density. The optimal Pb/Cs ratio for achieving the best photoelectric performance shifted from 1:1 to 1.1:1 in the presence of MAI. Additionally, the incorporation of MAI allowed for more efficient longitudinal carrier transport, as evidenced by the enhanced photoluminescence (PL) intensity. The bandgap of CsPbI3 remained approximately at 1.7eV before the δ-phase transition, ensuring suitability for photovoltaic applications. Ultimately, a photovoltaic device with 12% efficiency is achieved in the p-i-n structure without additional post-annealing of the CsPbI3 perovskite films, demonstrating the practical benefits of MAI incorporation.

Influence of post-thermal treatment on characteristics of polycrystalline hybrid halide perovskite nanoparticles thin film

A three-dimensional organic–inorganic hybrid halide perovskite (CH3NH3PbI2Br) nanoparticle film was synthesized using solution process in one step. Precursors’ stoichiometry was used to prepare methylammonium bromide and lead (II) bromide in dimethyl formamide. The synthesized CH3NH3PbI2Br solution was spin coated on cleaned ITO prepatterned glass substrate at 2000 rpm. In addition, the influence of post-thermal treatment on the deposited nanoparticles films was evaluated by studying the structural, optical and morphological properties using X-ray Diffraction (XRD), Fourier Transform Infrared (FTIR) spectrometry, UV–visible spectrophotometry, Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM). The average crystallite sizes were calculated to be ~ 8.0, ~ 9.4, ~ 11.3 and ~ 13.1 nm of as-prepared and annealed films at 400, 500 and 600 °C, respectively. Besides, the bandgaps of 2.22 eV, 1.96 eV, 1.89 eV and 1.63 eV were extrapolated for as-prepared and annealed films at 400 °C, 500 °C and 600 °C, respectively. From J–V curves, the Jsc values of 9.4, 10.6, 11.7 and 12.8 mAcm−2, FF values of 56.99%, 57.25%, 58.94% and 59.26% and PCE values of 2.99%, 3.49%, 3.96% and 4.39% were calculated for as-prepared and annealed CH3NH3PbI2Br films at 400 °C, 500 °C and 600 °C, respectively. The percentage enhancement values of 14.32%, 24.49% and 31.89% compared to as-prepared CH3NH3PbI2Br film. Hence, post-thermal treatment of organic–inorganic halide perovskite material improved its photoconversion efficiency without sacrificing its dimensionality.