Cs2SnI6 Perovskite Research Articles

Preparation of Cs2SnI6 perovskite thin films based on solvent engineering and their properties of photodetectors

Preparation of Cs2SnI6 perovskite thin films based on solvent engineering and their properties of photodetectors

The development of a bilayer absorption scenario of CsPbI3/Cs2SnI6 PSCs for enhanced efficiency and stability

The introduction of heterojunction structures in perovskite solar cells (PSCs) can lead to substantial enhancements in power conversion efficiency (PCE) and stability. Using the SCAPS-1D software, we have theoretically investigated the performance potential of CsPbI3/Cs2SnI6 heterojunction PSCs. The purpose of incorporating a thin layer of Cs2SnI6 perovskite onto the CsPbI3 layer is to enhance the stability of the device through the formation of a protective barrier that prevents the continuous degradation of CsPbI3. The device's overall efficiency was found to be greatly enhanced by meticulously optimizing the acceptor concentration (NA), defect density (Nt), and absorber thickness of CsPbI3. In addition, the influence of various physical parameters such as the operating temperature, the work function of the metal rear contact, and series and shunt resistance on the photovoltaic performance of the device is comprehensively examined. With the systematic optimization of these parameters, the device exhibited improved performance and attained an outstanding PCE of 20.86 %, an open circuit voltage (VOC) of 1.19 V, a fill factor (FF) of 81.77%, and a current density voltage (JSC) of 21.32 mA/cm2. We think that our work will provide theoretical guidance in the advancement of heterojunction devices with much improved efficiency and stability.

Effect of Lewis acid-base additive on lead-free Cs2SnI6 thin film prepared by direct solution coating process

Abstract Inorganic Cs2SnI6 perovskite has exhibited substantial potential for light harvesting due to its exceptional optoelectronic properties and remarkable stability in ambient conditions. The charge transport characteristics within perovskite films are subject to modulation by various factors, including crystalline orientation, morphology, and crystalline quality. Achieving preferred crystalline orientation and film morphology via a solution-based process is challenging for Cs2SnI6 films. In this work, we employed thiourea as an additive to optimize crystal orientation, enhance film morphology, promote crystallization, and achieve phase purity. Thiourea lowers the surface energy of the (222) plane along the ＜111＞ direction, confirmed by X-ray diffraction, X-ray photoelectron spectroscopy, ultraviolet photoelectron spectroscopy studies, and density functional theory calculations. Varying thiourea concentration enables a bandgap tuning of Cs2SnI6 from 1.52 eV to 1.07 eV. This approach provides a novel method for utilizing Cs2SnI6 films in high-performance optoelectronic devices.

Design and fabrication of all-inorganic transport materials-based Cs2SnI6 perovskite solar cells

Design and fabrication of all-inorganic transport materials-based Cs2SnI6 perovskite solar cells

Theoretical investigations of all inorganic Cs2SnI6 double perovskite solar cells for efficiency ∼ 30 %

Non-toxic and air-stable Cesium tin (IV) halide (Cs2SnI6) is a promising alternative to lead halide perovskite for photovoltaic applications. This study reports the extensive analysis of vacancy-ordered Cs2SnI6 perovskite as an efficient light harvester sandwiched between the n-ZnO electron transport layer (ETL) and different p-type metal oxides, namely CuBi2O4, Cu2O, CuAlO2, and NiO, hole transport layers (HTL), using SCAPS-1D software. Various physical parameters, viz. thickness, defect density (bulk and interfacial), and charge carrier concentration of different layers for the device architecture of FTO/ZnO/Cs2SnI6/HTL/Au, are systematically investigated along with the effect of parasitic resistance, work function, and operating temperature in the quest for best device performance in terms of photoconversion efficiency (PCE). The effect of DC biasing voltage is analyzed using C-V characteristics to understand the spatial charge distribution, absorber doping profile, and junction built-in potential. The frequency-dependent admittance was studied using simulated C-f characteristics to give an insight into the defect and the conductance. The Cesium tin (IV) halide (Cs2SnI6) based device optimized with CuBi2O4, Cu2O, CuAlO2, and NiO HTLs has shown PCE of 28.18 %, 29.72 %, 29.43 %, and 29.33 %, respectively.

Strain effects on electronic, optical properties and carriers mobility of Cs2SnI6 vacancy‐ordered double perovskite: A promising photovoltaic material

AbstractPerovskite halides have attracted substantial attention as materials for solar cell applications because of their fascinating optoelectronic and photovoltaic properties. We report the results of the first‐principles calculations of the strain effects on electronic and optical properties and carrier mobility of vacancy‐ordered Cs2SnI6 double perovskite. The calculated band gap energy of unstrained Cs2SnI6 is about 1.257 eV when using the Tran‐Blaha modified Becke Johnson (mBJ) exchange potential, which is in good agreement with experimental measurements. Under the applied strains, the energy band gap value increases up to 1.316 eV for −4% compressive strain and decreases to 1.211 eV for 4% tensile strain. This effect is mainly due to the fact that the conduction band minimum shifts under compressive and tensile strains. Based on carrier mobility calculations, we notice that under tensile strain the hole and electron carrier mobility diminish, whereas the carrier mobility increases by 16.3% for electrons and by 9.1% for holes under −4% compressive strain. Moreover, data of the calculated optical constants indicate that applied strains can affect the optical properties of Cs2SnI6 perovskite.

Incorporation of Perovskite Cs2SnI6 into Dye Sensitized Solar Cell Structure and Its Optimization

Generation of Dye Sensitized Solar Cell (DSSC) has become one of considerable research in the solar cell technology in the last two decades due to the ease of fabrication process. Several studies have been conducted to improve DSSC performance, for example by modifying the structure of DSSC or by adding perovskite material and metal nanoparticles (Au or Ag). Because lead is toxic and has a negative impact to the environment, other perovskite type of materials that are more environmentally friendly are needed. Tin based perovskite (Cs2SnI6) is known more stable in air than Pb based perovskite and it can be synthesized in an air environment. In this study, we attempt to synthesis Cs2SnI6 perovskite and incorporate the material into N719 dye solution in order to enhance the performance of DSSC. Cs2SnI6 was synthesized by simple chemical mixing at room temperature from CsI and stannic iodide (SnI4). The absorbance spectra of Cs2SnI6 perovskite show two specific peaks at wavelength of 293 nm and 362 nm. The energy band gap obtained by the Tauc-Plot method is about 3.1 eV. The performance of our fabricated DSSC device was done by J-V measurement. In our experiment, the addition of Cs2SnI6 into N719 dye solution in DSSC structure reveals the highest PCE value of 3.97% in comparison to PCE value of reference that is about 1.56%. However, the PCE value was drastically reduced from 4.03% in the 1st week to 1.07% in the 9th week for the case of device with addition ethanol solvent in perovskite

Temperature dependence of the vibrational and emission spectra in the 0D vacancy-ordered Cs2SnI6 perovskite

Structural and electronic properties of the air-stable Cs2SnI6 defect perovskite have been investigated by applying Raman and photoluminescence spectroscopies in a temperature range of 83 to 433 K. Upon increasing the temperature, the internal Sn-I Raman bands weakly shift to lower energy and broaden. Interestingly, vibrations of Cs atoms against the SnI6 octahedra are only observed above 293 K, activated by the dynamic lattice anharmonicity. Such lattice modes potentially influence charge-carrier mobilities as well as thermal conductivity of the materials. Intriguing emission properties are also observed with very strong (but not uniform) photoluminescence signals that present high-energy shifts on temperature.

RETRACTED ARTICLE: Fabrication and characterization of Cs2SnI6 perovskite films using SnI2 and I2 powders as reactants

In the recent years, cesium tin iodide (Cs2SnI6) double perovskite has emerged as a research hotspot in photovoltaics due to its exceptional stability and outstanding optoelectronic properties. In this work, we have utilized a reactant combination of SnI2 and I2 to prepare uniform Cs2SnI6 films via modified two-step process. The impact of the reaction conditions on the structural, morphological and optical properties is explored. It is found that optimizing the reaction conditions improves the phase stability and morphology of the films. The iodine-rich fabrication of the films ensued in enhanced PL and optical characteristics of the Cs2SnI6 with an optimal bandgap in the range of 1.21–1.34 eV. Additionally, we fabricated and simulated photovoltaic devices (FTO/TiO2/Cs2SnI6/SnO/Au) utilizing the optimized Cs2SnI6 films.

Single-atom Pt-I3 sites on all-inorganic Cs2SnI6 perovskite for efficient photocatalytic hydrogen production

Organic-inorganic lead halide perovskites are a new class of semiconductor materials with great potential in photocatalytic hydrogen production, however, their development is greatly plagued by their low photocatalytic activity, instability of organic component and lead toxicity in particular. Herein, we report an anti-dissolution environmentally friendly Cs2SnI6 perovskite anchored with a new class of atomically dispersed Pt-I3 species (PtSA/Cs2SnI6) for achieving the highly efficient photocatalytic hydrogen production in HI aqueous solution at room temperature. Particularly, we discover that Cs2SnI6 in PtSA/Cs2SnI6 has a greatly enhanced tolerance towards HI aqueous solution, which is very important for achieving excellent photocatalytic stability in perovskite-based HI splitting system. Remarkably, the PtSA/Cs2SnI6 catalyst shows a superb photocatalytic activity for hydrogen production with a record turnover frequency of 70.6 h−1per Pt, about 176.5 times greater than that of Pt nanoparticles supported Cs2SnI6 perovskite, along with superior cycling durability. Charge-carrier dynamics studies in combination with theory calculations reveal that the dramatically boosted photocatalytic performance on PtSA/Cs2SnI6 originates from both unique coordination structure and electronic property of Pt-I3 sites, and strong metal-support interaction effect that can not only greatly promote the charge separation and transfer, but also substantially reduce the energy barrier for hydrogen production. This work opens a new way for stimulating more research on perovskite composite materials for efficient hydrogen production.

Synthesis of Cs2SnI6 perovskite thin film by low-pressure chemical vapor deposition method

Cs2SnI6 is an all-inorganic, air-stable and Pb-free halide perovskite material. In this work, we propose a low-pressure chemical vapor deposition method that enables the synthesis of continuous Cs2SnI6 thin films. Some technical parameters such as the deposition time and the deposition temperature of CsI were varied to investigate the morphology and thickness of Cs2SnI6 thin films. The film was further undergone an annealing treatment in SnI4 ambient to enhance characteristics, such as the long-term stability and the structural, optical and electrical properties. After annealing in SnI4, the film was found to be stable in ambient air (40–60% humidity) for 30 days. The film shows n-type semiconducting with an energy bandgap of 1.58 eV. Its absorption coefficient is higher than 3.4 × 104 cm−1 in the visible region with a maximum value of 0.9 × 105 cm−1 at the wavelength of 420 nm. The carrier concentration increased to 5.5 × 1017 cm−3, and the resistivity declined to 3.1 Ω.cm.

Lead‐Free Cs2SnI6 Perovskites for Optoelectronic Applications: Recent Developments and Perspectives

Since the booming research on perovskite solar cells (PSCs), organic–inorganic hybrid halide perovskites have triggered widespread research attention. This is seen in the unprecedented improvement of the power conversion efficiency (PCE) from an initial 3.8% to a remarkable 25.5%. Despite the fascinating improvement in PCEs, the toxicity of the detrimental lead element is a major limiting factor that hampers the commercialization prospect of lead‐based materials. Extensive efforts have been dedicated to the progress of lead‐free, stable, and ecofriendly perovskite materials for green‐energy applications. Recently, double‐halide Cs2SnI6 perovskite emerged as a star material due to its favorable optoelectronic properties, stable nature, and environmental friendliness. Thus, an in‐time review to recapitulate the recent advances of Cs2SnI6 is critical to provide viable theoretical and experimental strategies for synergic optimization of perovskite films. Herein, the theoretical and experimental understandings of the properties of Cs2SnI6 are summarized and the different fabrication methodologies and their influences on the properties of Cs2SnI6 are discussed. The application potential of Cs2SnI6 is further reviewed and the limiting factors that influence the performance of Cs2SnI6 devices are highlighted. In the end, prospective research directions to improve the optoelectronic properties are presented for developing efficient Cs2SnI6 devices.

A feasible process for lead-free Cs2SnI6 films using vapor-assisted deposition method with Sn and I2 powders as reactants

As potential candidates for organic–inorganic hybrid perovskite materials, Pb-free Cs2SnI6 has gained considerable attention because of their better stability under atmospheric conditions containing oxygen and water vapor. Herein, we fabricate Cs2SnI6 films using the vapor-assisted deposition method with Sn and I2 powders as reactants. To obtain uniform and pure Cs2SnI6 films, two different reaction systems are applied and the properties of the samples are characterized via x-ray diffraction, scanning electron microscopy, UV–vis spectrometer, photoluminescence, and Hall-effect measurements. All the results showed a strong dependency on the reaction temperature and fabrication approach. Based on the preparation process in a closed system, we successfully inhibited the high temperature decomposition of Cs2SnI6 even at 250 °C. However, in the open system, the reaction temperature of Cs2SnI6 films should not be higher than 200 °C. Finally, n-type semiconducting Cs2SnI6 films with bandgap (E g) of 1.32–1.54 eV, carrier concentration of 1013–1016 cm−3, and carrier mobility above 100 cm2 V−1 s−1 are obtained due to the generated I-rich synthesis condition. We believe that our findings will provide beneficial guidance for the fabrication of Cs2SnI6 perovskite solar cells.

Kinetically Controlled Growth of Sub-Millimeter 2D Cs2 SnI6 Nanosheets at the Liquid-Liquid Interface.

Cs2 SnI6 perovskite displays excellent air stability and a high absorption coefficient, promising for photovoltaic and optoelectronic applications. However, Cs2 SnI6 -based device performance is still low as a result of lacking optimized synthesis approaches to obtain high quality Cs2 SnI6 crystals. Here, a new simple method to synthesize single crystalline Cs2 SnI6 perovskite at a liquid-liquid interface is reported. By controlling solvent conditions and Cs2 SnI6 supersaturation at the liquid-liquid interface, Cs2 SnI6 crystals can be obtained from 3D to 2D growth with controlled geometries such as octahedron, pyramid, hexagon, and triangular nanosheets. The formation mechanisms and kinetics of complex shapes/geometries of high quality Cs2 SnI6 crystals are investigated. Freestanding single crystalline 2D nanosheets can be fabricated as thin as 25 nm, and the lateral size can be controlled up to sub-millimeter regime. Electronic property of the high quality Cs2 SnI6 2D nanosheets is also characterized, featuring a n-type conduction with a high carrier mobility of 35 cm2 V-1 s-1 . The interfacial reaction-controlled synthesis of high-quality crystals and mechanistic understanding of the crystal growth allow to realize rational design of materials, and the manipulation of crystal growth can be beneficial to achieve desired properties for potential functional applications.

Investigation of air-stable Cs2SnI6 films prepared by the modified two-step process for lead-free perovskite solar cells

In recent years, the organic-inorganic perovskite materials have revolutionized the Photovoltaic industry with highly efficient power conversion devices accompanied by a high growth rate. However, these devices experience major environmental and stability issues that hinder their true potential. More recently, a rarely studied perovskite material Cs2SnI6 is gaining enormous attention due to its superior stability and suitable bandgap. In this work, we developed a modified two-step process to prepare uniform Cs2SnI6 films, and the influence of the reaction conditions on the properties is explored. The structural, morphological, optical, and electrical properties of the prepared films were investigated using x-ray diffraction, Raman spectroscopy, scanning electron microscopy, UV–vis spectrometer, photoluminescence, and Hall Effect measurements, respectively. Phase stability and morphology of the films are improved with optimizing the reaction conditions. The results confirm the n-type semiconductor nature of Cs2SnI6 with bandgap ranging from 1.29 eV to 1.42 eV with maximum carrier mobility of 425 cm2 V−1 s−1. The present study will further provide potential research directions in improving the device efficiency of air-stable Cs2SnI6 perovskite solar cells.

Performance of Air-Stable Cs<sub>2</sub>SnI<sub>6</sub> Perovskite as Electron Transport Layer in Inverted Bulk Heterojunction Solar Cell

In recent years, perovskite material has been extensively studied due to its unique physical properties and promising application in the third generation of solar cells. In particular, Sn-based perovskite has been considered to replace Pb-based perovskite because of the toxic effects and it can lead to other serious problems related to the environment. Cs2SnI6 perovskite has been known to be synthesized in a simple chemical process and it can be produced on a large scale. Moreover, this material is also oxygen and moisture stable due to the high oxidation state of tin. In this study, we synthesize air-stable Cs2SnI6 perovskite by the use of the wet chemical process at room temperature. Next, we attempt to fabricate the inverted bulk heterojunction solar cells incorporated Cs2SnI6 as electron transport layer in the configuration of ITO/ZnO/Cs2SnI6/P3HT:PCBM/PEDOT:PSS/Ag to improve device performance. The Cs2SnI6 perovskite shows an Fm-3m space group with a cubic lattice parameter of 11.62Å confirmed by X-Ray Diffraction (XRD) measurement, while UV-Vis measurement indicates this type of perovskite has direct band gap ~3.1 eV. The fabricated solar cell device reveals the enhancement in current density at short circuit condition (Jsc) from 64.69 mA/cm2 to 77.02 mA/cm2 with the addition of 2.25 mg/ml Cs2SnI6 along with the enhancement of power conversion efficiency (PCE) from 7.05% to 9.75% as characterized by J-V measurement. In our case, the voltage at open circuit condition (Voc) of the device does not perform significant improvement. Besides, it is found that the solar cell devices are quite stable even after exposure in the air for six weeks after fabrication, as indicated by PCE performance.

Effect of Lead-Free Perovskite Cs<sub>2</sub>SnI<sub>6</sub> Addition in the Structure of Dye-Sensitized Solar Cell

Over the past few years, metal halide perovskites have been considered as a promising material for application in photovoltaic devices because of its unique optical and electrical properties. In particular, Sn-based perovskites have been being considered to replace Pb-based perovskite because of the Pb toxicity that will raise serious concerns on the environmental issue. In this report, we present our attempt to synthesize the Sn-based perovskite (namely, Cs2SnI6), which is air and thermal stable, and use it as an electron transport layer in dye-sensitized solar cells (DSSC) for improving its power conversion efficiency. The synthesize of Cs2SnI6 perovskite was done by mixing Cs2CO3 in HI and SnI4 in ethanol to form a precipitate at room temperature. The purification process was an important part to collect effectively the synthesis product. The fabrication of DSSC was done by a standard process based on the screen printing and spin-coating techniques, while the characterization of Cs2SnI6 was done by UV-Vis spectroscopy and XRD measurement. In the present experiment, the addition of the Cs2SnI6 layer was performed by spin coating the Cs2SnI6 solution onto the TiO2 mesoporous layer. The photovoltaic performance of the fabricated DSSC shows a significant enhancement in the short circuit photocurrent density (Jsc) and conversion efficiency, that is, from 15.04 mA/cm2 to 16.33 mA/cm2 from 5.7% to 6.75% due to the incorporation of spin-coated 5 mM Cs2SnI6 in comparison to the reference cell without Cs2SnI6.

Tin fluoride assisted growth of air stable perovskite derivative Cs2SnI6 thin film as a hole transport layer

Dye sensitized solar cells are promising low-cost and environmentally friendly alternatives to conventional semiconductor solar cells. However, the use of liquid electrolytes containing the iodide/tri-iodide redox couple causes long-term problems such as electrode corrosion and electrolyte leakage. Here we report the facile low-temperature solution approach to fabricate the perovskite derivative Cs2SnI6 thin film as an alternative hole conductor for solid state dye sensitized solar cells under ambient air condition. Impact of the addition of tin fluoride (SnF2) on the crystalline structure, morphology and optoelectronic properties of cesium-tin-iodide thin films was investigated. The absorbance spectrum exhibited a band gap value of 1.27 eV of semiconducting Cs2SnI6 perovskite derivative. Hall Effect measurement showed the improved mobility of SnF2 treated Cs2SnI6 thin films. The 10% SnF2 treated Cs2SnI6 thin films achieved the highest mobility with the value of 468.1 cm2.V−1.s−1. These findings demonstrated the suitability of perovskite derivative Cs2SnI6 thin film as a hole transport layer as well as a promising light harvesting layer for solar cell applications.

In Situ Construction of a Cs2SnI6 Perovskite Nanocrystal/SnS2 Nanosheet Heterojunction with Boosted Interfacial Charge Transfer.

Heterojunction engineering has played an indispensable role in the exploitation of innovative artificial materials with exceptional properties and has consequently triggered a new revolution in achieving high-performance optoelectronic devices. Herein, an intriguing halide perovskite (PVK) and metal dichalcogenide (MD) heterojunction, i.e., a lead-free Cs2SnI6 perovskite nanocrystal/SnS2 nanosheet hybrid, was fabricated in situ for the first time. Comprehensive investigations with experimental characterizations and theoretical calculations demonstrate that cosharing of the Sn atom enables intimate contact in the Cs2SnI6/SnS2 hybrid together with a type II band alignment structure. Additionally, ultrafast carrier separation between SnS2 and Cs2SnI6 has been observed in the Cs2SnI6/SnS2 hybrid by transient absorption measurements, which efficiently prolongs the lifetime of the photogenerated electrons in SnS2 (from 1290 to 3080 ps). The resultant spatial charge separation in the Cs2SnI6/SnS2 hybrid evidenced by Kelvin probe force microscopy (KPFM) significantly boosts the photocatalytic activity toward CO2 reduction and the photoelectrochemical performance, with 5.4-fold and 10.6-fold enhancements compared with unadorned SnS2. This work provides a facile and effective method for the in situ preparation of PVK-MD heterojunctions, which may significantly stimulate the synthesis of various perovskite-based hybrid materials and their further optoelectronic applications.

Photocurrent enhancement by incorporation of air-stable Cs2SnI6 Perovskite in dye-sensitized solar cell

Cs2SnI6 is an inorganic lead-free perovskite variant which is air and thermal stable and its application in the third generation of photovoltaic devices is undergoing rapid expansion over the past few years. This paper presents a fabrication of dye-sensitized solar cell (DSSC) with the incorporation of Cs2SnI6 perovskite in the active layer of N-719 dye. The absorbance spectra of N-719 dye on TiO2 mesoporous layer is found to increase by the addition of 2 wt% and 3 wt% of Cs2SnI6 in N719 dye in comparison to the reference of N-719 dye leading the role of Cs2SnI6 as photon absorber in the devices. Our fabricated DSSC device reveals a photocurrent enhancement from 6.36 mA/cm2 to 12.87 mA/cm2 by the addition of 3 wt% of Cs2SnI6, along with the enhancement of power conversion efficiency from 1.71% to 3.94%.