Sn-based Perovskites Research Articles

Optimizing inorganic double halide (Cs2TiI6) perovskite solar cell for different hole transport layers using solar cell capacitance software (SCAPS-ID)

Although the organic-inorganic Pb-based (CH3NH3PbI3) and Sn-based (CH3NH3SnI3) perovskite solar cells (PSC) have attained higher efficiency but due to toxicity and instability, the inorganic, Ti-based (Cs2TiI6) PSC can be a potential alternative. So, the current paper focuses on determining open circuit voltage (VOC), short circuit current density (JSC), fill factor (FF), power conversion efficiency (PCE) and quantum efficiency (QE) for the inorganic PSC by changing temperature, thickness, band gaps and hole transport layers (HTLs) using solar cell capacitance software (SCAPS-ID). Three different types of Ti-based perovskite solar cell structures have been investigated by varying three types of HTL. Results yield that structure 1 (TCO/ZnO/Cs2TiI6/CdTe/Au) cedes higher PCE of 23.51 % with VOC 1.23 V, JSC 22.49 mA/cm2 and FF 84.77 % for the band gap of 1.7 eV and 500 nm thickness of the absorber layer, at 300 K temperature in comparison with other structures. The maximum efficiency of approximately 98 % has also been found for all simulated structures for the wavelength of around 360 nm.

Exciton Localization for Highly Luminescent Two-Dimensional Tin-Based Hybrid Perovskites through Tin Vacancy Tuning.

Exciton localization is an approach for preparing highly luminescent semiconductors. However, realizing strongly localized excitonic recombination in low-dimensional materials such as two-dimensional (2D) perovskites remains challenging. Herein, we first propose a simple and efficient Sn2+ vacancy (VSn ) tuning strategy to enhance excitonic localization in 2D (OA)2 SnI4 (OA=octylammonium) perovskite nanosheets (PNSs), increasing their photoluminescence quantum yield (PLQY) to ≈64 %, which is among the highest values reported for tin iodide perovskites. Combining experimental with first-principles calculation results, we confirm that the significantly increased PLQY of (OA)2 SnI4 PNSs is primarily due to self-trapped excitons with highly localized energy states induced by VSn . Moreover, this universal strategy can be applied for improving other 2D Sn-based perovskites, thereby paving a new way to fabricate diverse 2D lead-free perovskites with desirable PL properties.

Origin of Enhanced Nonradiative Carrier Recombination Induced by Oxygen in Hybrid Sn Perovskite

Oxygen ingression has been shown to substantially decrease the carrier lifetime of Sn-based perovskites, behind which the mechanism remains yet unknown. Our first-principles calculations reveal that in prototypical MASnI3 (MA = CH3NH3), oxygen by itself is not a recombination center. Instead, it tends to form substitutional OI through combining with native I vacancies (VI) and remarkably increases the original recombination rate of VI by 2-3 orders of magnitude. This rationalizes the experimentally observed sharp decline of carrier lifetime in perovskites exposed to air. The significantly enhanced carrier recombination is due to a smaller electron capture barrier of OI, resulting from lattice strengthening and the suppressed structural relaxation upon electron capture. These insights offer a route to further improve device performance via anion engineering in broad Sn-based perovskite optoelectronics operating in ambient air. Moreover, our results highlight the important role of lattice relaxation for nonradiative carrier capture in materials in general.

Substitution of Ethylammonium Halides Enabling Lead-Free Tin-Based Perovskite Solar Cells with Enhanced Efficiency and Stability

Tin (Sn)-based perovskite solar cells (PSCs) have attracted extensive attention due to the irlow toxicity and excellent optoelectric properties. Nonetheless, the development of Sn-based PSCs is still hampered by poor film quality due to the fast crystallization and the oxidation from Sn2+ to Sn4+. In this work, we compare and employ three ethylammonium halides, EAX (X = Cl, Br, I) to explore their roles in Sn-based perovskites and solar cells. We find that crystallinity and crystallization orientation of perovskites are optimized with the regulation of EAI. EABr leads to reduced defect density and enhanced crystallinity but also the lowest absorption and the widest band gap owing to the substitution of Br-. Notably, perovskites with EACl exhibit the best crystallinity, lowest defect density, and excellent antioxidant capacity benefiting from the partial substitution of Cl-. Consequently, the EACl-modified device achieves a champion PCE of 12.50% with an improved Voc of 0.79 V. Meanwhile, an unencapsulated EACl device shows excellent shelf stability with negligible efficiency degradation after 5400 h of storage in a N2-filled glovebox, and the encapsulated device retains its initial efficiency after continuous light illumination at the maximum power point for 100 h in air.

Resolving Oxidation States and X–site Composition of Sn Perovskites through Auger Parameter Analysis in XPS (Adv. Mater. Interfaces 7/2023)

Resolving Chemical States in Sn-Based Perovskites In article 2201828, Alexander Wieczorek, Sebastian Siol, and colleagues demonstrate how Auger parameter analysis enables more reliable chemical state analysis of Sn-based perovskites. Through systematic compositional variation a high sensitivity of this parameter on the X-site composition and oxidation state of Sn-based perovskites is demonstrated. The latter aspect can be used to detect and understand aging of these compounds under ambient conditions. This approach can be easily adopted using standard XPS equipment and enables better reproducibility of results across laboratories. [Artwork by Alexander Wieczorek]

Correction to: Numerical study of eco-friendly Sn-based Perovskite solar cell with 25.48% efficiency using SCAPS-1D

Correction to: Numerical study of eco-friendly Sn-based Perovskite solar cell with 25.48% efficiency using SCAPS-1D

Effect of bromide incorporation on the electronic & photovoltaic properties of Sn-based perovskite devices: A multiscale investigation utilizing first principles approach and numerical simulation, aided by machine learning models

In this study, the effects of Bromide doping into iodide sites in cesium tin triiodide (CsSnI3), methylammonium tin triiodide (MASnI3) and formamidinium tin triiodide (FASnI3), were investigated using a novel multiscale computational approach. Density functional theory (DFT) was used to probe the impact of Br addition on the electronic structure and the bandgap, while Solar Cell Capacitance Simulator (SCAPS) was used to numerically simulate & optimize solar devices containing these perovskite absorbers. A set of supervised machine learning algorithms were used to model the relationship between SCAPS input and output parameters to determine which input parameters have significant contributions to solar cell efficiency. This information was used to couple DFT & SCAPS; allowing the use of accurate band gap values predicted by DFT-1/2 approach, as inputs in device scale simulations. The novel framework was then successfully applied to predict the combined effect of bromide concentration and solar cell geometry on the power conversion efficiency (PCE). Furthermore, the predicted trends were explained both in the context of the underlying electronic structures and device performance parameters. For a set of common device configurations our work predicted maximum efficiencies of 4.08 %, 9.61 % and 12.1 % for pristine CsSnI3, MASn(I0.75Br0.25)3 and FASn(I0.75Br0.25)3 with absorber layer thicknesses of 400 nm, 300 nm and 600 nm respectively. These results highlight the potential of our computational approach in predicting the impact of perovskite stoichiometry on the device performance as a function of modifications to the electronic structure.

Numerical study of eco-friendly Sn-based Perovskite solar cell with 25.48% efficiency using SCAPS-1D

Numerical study of eco-friendly Sn-based Perovskite solar cell with 25.48% efficiency using SCAPS-1D

Suppressing Disproportionation Decomposition in Sn-Based Perovskite Light-Emitting Diodes

Nontoxic Sn-based perovskite light-emitting diodes (Pero-LEDs) have been developing rapidly in recent years. However, high-quality Sn-based perovskite films are hardly prepared because of the heavy self-doping of Sn4+ in the as-prepared films. Most previous reports indicate that the Sn4+ formation is mainly attributed to the Sn2+ oxidation by external oxidizers. Here, for the first time, we reveal that the disproportionation decomposition of Sn2+ during the annealing process plays a critical role in degrading device performance. To resolve this issue, we introduced formamidine thiocyanate into the perovskite precursor as a thermal-sacrificial agent to alleviate the disproportionation decomposition. Finally, we achieved efficient Pero-LEDs with a maximum external quantum efficiency of 5.3% and ultralow efficiency roll-off. This work provides a view of understanding the instability of Sn-based perovskite and presents a practical method to achieve efficient Sn-based Pero-LEDs by suppressing the disproportionation decomposition of Sn2+.

UV-VIS-NIR broadband flexible photodetector based on layered lead-free organic-inorganic hybrid perovskite.

The flexible photodetector is viewed as a research hotspot for numerous advanced optoelectronic applications. Recent progress has manifested that lead-free layered organic-inorganic hybrid perovskites (OIHPs) are highly attractive to engineering flexible photodetectors due to the effective overlapping of several unique properties, including efficient optoelectronic characteristics, exceptional structural flexibility, and the absence of Pb toxicity to humans and the environment. The narrow spectral response of most flexible photodetectors with lead-free perovskites is still a big challenge to practical applications. In this work, we demonstrate the flexible photodetector based on a novel (to our knowledge) narrow-bandgap OIHP of (BA)2(MA)Sn2I7, with achieving a broadband response across an ultraviolet-visible-near infrared (UV-VIS-NIR) region as 365-1064 nm. The high responsivities of 28.4 and 2.0 × 10-2 A/W are obtained at 365 and 1064 nm, respectively, corresponding to detectives of 2.3 × 1010 and 1.8 × 107 Jones. This device also shows remarkable photocurrent stability after 1000 bending cycles. Our work indicates the huge application prospect of Sn-based lead-free perovskites in high-performance and eco-friendly flexible devices.

Performance Enhancement of Lead-Free 2D Tin Halide Perovskite Transistors by Surface Passivation and Its Impact on Non-Volatile Photomemory Characteristics.

Two-dimensional(2D) tin(Sn)-based perovskites have recently received increasing research attention for perovskite transistor application. Although some progress is made, Sn-based perovskites have long suffered from easy oxidation from Sn2+ to Sn4+ , leading to undesirable p-doping and instability. In this study, it is demonstrated that surface passivation by phenethylammonium iodide (PEAI) and 4-fluorophenethylammonium iodide (FPEAI) effectively passivates surface defects in 2Dphenethylammonium tin iodide(PEA2 SnI4 )films, increases the grain size by surface recrystallization, and p-dopes the PEA2 SnI4 film to form a better energy-level alignment with the electrodes and promote charge transport properties. As a result, the passivated devices exhibit better ambient and gate bias stability, improved photo-response, and higher mobility, for example, 2.96 cm2 V-1 s-1 for the FPEAI-passivated films-four times higher than the control film (0.76 cm2 V-1 s-1 ). In addition, these perovskite transistors display non-volatile photomemory characteristics and are used as perovskite-transistor-based memories. Although the reduction of surface defects in perovskite films results in reduced charge retention time due to lower trap density, these passivated devices with better photoresponse and air stability show promise for future photomemory applications.

A Review on the Progress, Challenges, and Performances of Tin-Based Perovskite Solar Cells.

In this twenty-first century, energy shortages have become a global issue as energy demand is growing at an astounding rate while the energy supply from fossil fuels is depleting. Thus, the urge to develop sustainable renewable energy to replace fossil fuels is significant to prevent energy shortages. Solar energy is the most promising, accessible, renewable, clean, and sustainable substitute for fossil fuels. Third-generation (3G) emerging solar cell technologies have been popular in the research field as there are many possibilities to be explored. Among the 3G solar cell technologies, perovskite solar cells (PSCs) are the most rapidly developing technology, making them suitable for generating electricity efficiently with low production costs. However, the toxicity of Pb in organic-inorganic metal halide PSCs has inherent shortcomings, which will lead to environmental contamination and public health problems. Therefore, developing a lead-free perovskite solar cell is necessary to ensure human health and a pollution-free environment. This review paper summarized numerous types of Sn-based perovskites with important achievements in experimental-based studies to date.

High-member low-dimensional Sn-based perovskite solar cells

High-member low-dimensional Sn-based perovskite solar cells

Unusual Spectrally Reproducible and High Q-Factor Random Lasing in Polycrystalline Tin Perovskite Films.

An unusual spectrally reproducible near-IR random lasing (RL) with no fluctuation of lasing peak wavelength is disclosed in polycrystalline films of formamidinium tin triiodide perovskite, which have been chemically stabilized against Sn2+ to Sn4+ oxidation. Remarkably, a quality Q-factor as high as ≈104 with an amplified spontaneous emission (ASE) threshold as low as 2µJcm-2 (both at 20K) are achieved. The observed spectral reproducibility is unprecedented for semiconductor thin film RL systems and cannot be explained by the strong spatial localization of lasing modes. Instead, it is suggested that the spectral stability is a result of such an unique property of Sn-based perovskites as a large inhomogeneous broadening of the emitting centers, which is a consequence of an intrinsic structural inhomogeneity of the material. Due to this, lasing can occur simultaneously in modes that are spatially strongly overlapped, as long as the spectral separation between the modes is larger than the homogeneous linewidth of the emitting centers. The discovered mechanism of RL spectral stability in semiconductor materials, possessing inhomogeneous broadening, opens up prospects for their practical use as cheap sources of narrow laser lines.

Achieving above 24% efficiency with non-toxic CsSnI3 perovskite solar cells by harnessing the potential of the absorber and charge transport layers.

Lead toxicity is a barrier to the widespread commercial manufacture of lead halide perovskites and their use in solar photovoltaic (PV) devices. Eco-friendly lead-free perovskite solar cells (PSCs) have been developed using certain unique non- or low-toxic perovskite materials. In this context, Sn-based perovskites have been identified as promising substitutes for Pb-based perovskites due to their similar characteristics. However, Sn-based perovskites suffer from chemical instability, which affects their performance in PSCs. This study employs theoretical simulations to identify ways to improve the efficiency of Sn-based PSCs. The simulations were conducted using the SCAPS-1D software, and a lead-free, non-toxic, and inorganic perovskite absorber layer (PAL), i.e. CsSnI3 was used in the PSC design. The properties of the hole transport layer (HTL) and electron transport layer (ETL) were tuned to optimize the performance of the device. Apart from this, seven different combinations of HTLs were studied, and the best-performing combination was found to be ITO/PCBM/CsSnI3/CFTS/Se, which achieved a power conversion efficiency (PCE) of 24.73%, an open-circuit voltage (VOC) of 0.872 V, a short-circuit current density (JSC) of 33.99 mA cm-2 and a fill factor (FF) of 83.46%. The second highest PCE of 18.41% was achieved by the ITO/PCBM/CsSnI3/CuSCN/Se structure. In addition to optimizing the structure of the PSC, this study also analyzes the current density-voltage (J-V) along with quantum efficiency (QE), as well as the impact of series resistance, shunt resistance, and working temperature, on PV performance. The results demonstrate the potential of the optimized structure identified in this study to enhance the standard PCE of PSCs. Overall, this study provides important insights into the development of lead-free absorber materials and highlights the potential of using CsSnI3 as the PAL in PSCs. The optimized structure identified in this study can be used as a base for further research to improve the efficiency of Sn-based PSCs.

Zn2+ ion doping for structural modulation of lead-free Sn-based perovskite solar cells

A facile method of Zn ion doping into Sn-based perovskite through a redox potential difference causes lattice strain relaxation, resulting in the enhancement of optoelectronic properties.

Impact of two diammonium cations on the structure and photophysics of layered Sn-based perovskites

Layered metal-halide perovskites have shown great promise for applications in optoelectronic devices, where a large number of suitable organic cations give the opportunity to tune their structural and optical properties.

Biaxial strain improving carrier mobility for inorganic perovskite: ab initio Boltzmann transport equation

Inorganic halide perovskites have attracted interest due to their high efficiency and low cost. Considering the uncertainty of experimental measurements, it was important to predict the upper limit of carrier mobility. In this study, the ab initio Boltzmann transport equation, including all electron–phonon interactions, was used to accurately predict the mobilities of CsPbI3, CsSnI3, CsPbBr3, and CsSnBr3. Using the iterative Boltzmann transport equation (IBTE), the calculated mobility for CsPbI3 is µ e = 512/µ h = 379 cm2 V−1 s−1, and Sn-based perovskite exhibited high hole mobility. The longitudinal optical phonons associated with the stretching between halogen anions and divalent metal cations were revealed to be the dominant scattering source for the carriers. Furthermore, the effect of biaxial strain on mobility was investigated. We observed that biaxial compressive strain could improve the mobility of CsPbI3 and CsPbBr3. Surprisingly, under a compressive strain of , the mobilities of CsPbI3 using IBTE approach were improved to µ e = 1176/µ h = 936 cm2 V−1 s−1. It was revealed that the compressive strain could decrease the effective mass of CsPbI3 and CsPbBr3.

Stirring-Time Control Approach to Manage Colloid Nucleation Size for the Fabrication of High-Performance Sn-Based Perovskite Solar Cells.

Colloidal nucleation is first observed to exist in a Sn-based perovskite solution, and its components and size are discovered to alter in real time with stirring time. Then, a simple stirring-time control approach is developed to manage the size of the colloids, and with continuous stirring for 3 days an optimal colloid with size <10 nm is confirmed to successfully form a continuous, dense, high-quality perovskite film. Herein, the colloids exist in the form of [SnI6]4- complete coordination compounds, with which a compact FA0.75MA0.25SnI3 perovskite film with reduced defects and enhanced crystallinity concentration is obtained as nucleation sites, and a planar inverted perovskite solar cell with a champion power conversion efficiency of 10.74% is eventually realized. This work provides a novel perspective to enhance perovskite film quality and thus device performance via controlling high-quality nucleation in precursor solution.

Chlorine-Rich Substitution Enabled 2D3D Hybrid Perovskites for High Efficiency and Stability in Sn-Based Fiber-Shaped Perovskite Solar Cells

Chlorine-Rich Substitution Enabled 2D3D Hybrid Perovskites for High Efficiency and Stability in Sn-Based Fiber-Shaped Perovskite Solar Cells