Tin Triiodide Research Articles

A comparative numerical simulation study of CIGS solar cells with distinct back surface field layers for enhanced performance

The objective of this study is to explore the impact of various back surface field (BSF) layers including copper aluminium oxide (CuAlO2), Copper Antimony Sulphide (CuSbS2), Formamidinium tin triiodide (FASnI3), poly(3-hexylthiophene) P3HT to boost the output of conventional baseline CIGS solar cells structured. The device performance increases because of the minimized surface recombination velocity through heavily doped BSF layers, which increases the electric field at the rear contact. Among all proposed BSF layers CuAlO2 gives the best photoconversion efficiency (η) of 24.61% followed by fill factor (FF) of 83.11 %, short circuit current density (JSC) of 35.87 mA/cm2, and open circuit voltage (VOC) of 0.82 V with quantum efficiency (QE) of ∼92 % for the whole visible range with the onset happening at ∼ 560 nm, thanks to the enhancement of carrier collection when BSF layer is incorporated. The novelty in this work is that for the first time with the CuAlO2 BSF layer, 24.61% efficiency is reported at 1 μm CIGS layer thickness. We also examined how different BSFs affect the PV performance of the devices. The effect of temperature, the doping concentration of the BSFs, varying gallium proportion, JV & QE analysis, band diagram, and radiative recombination coefficient are varied to observe their impact on the PV parameters. This research introduces novel CIGS/CdS heterojunction configurations using various BSF layers to enhance efficiency, supporting the advancement of ultrathin, flexible, and tandem solar cell applications.

Simulation of high efficiency hybrid FTO/TiO2/CH3NH3SnI3/RGO based solar cell using SCAPS-1D

A hybrid structure of fluorine-doped tin oxide (FTO)/titanium dioxide (TiO2)/methylammonium tin triiodide (CH3NH3SnI3)/reduced graphene oxide (RGO) based solar cell has been designed and simulated using SCAPS-1D simulation tool. The three layers of the solar cell have been organized like TiO2 acting as an electron transporting layer (ETL), CH3NH3SnI3 serving as the photon absorption layer, and reduced graphene oxide (RGO) acting as the hole transporting layer (HTL). The thickness of the ETL and HTL layers are maintained at 300 nm each. The absorption layer thickness has been optimized and kept at 450 nm to get enhanced efficiency. The experimental absorption data from the referred articles of the materials are incorporated with the simulation to obtain convincing result. Simulated device parameters, such as efficiency, open-circuit voltage, short-circuit current density, and fill factor have been found to be 19.30 %, 1.070 V, 41.66 mA/cm2, and 43.27 %, respectively at 300 K temperature. Moreover, a study of the absorption layer defect density (109–1017 cm−2) has also been conducted for the device, revealing an almost inverse proportionality with the efficiency of the device. In addition, the device FTO/TiO2/CH3NH3SnI3/RGO has been examined with the various temperature range from 270 K to 400 K. The device, with a high offset band structure and high mobility ETL and HTL layers, shows promising candidate for solar cell applications.

Characterization of methylammonium tin iodide thin films prepared by sequential physical vapour deposition

Methylammonium tin triiodide (MASnI3) films were grown through Sequential Physical Vapour Deposition (SPVD) without breaking the vacuum and optimized by varying MAI thickness and annealing time while keeping SnI2 thickness constant. The film's crystallinity increased with MAI thickness and annealing time. Optimal bandgap was attained for the film with 500 nm MAI annealed for 20 & 40 min. FE-SEM revealed densely packed, large grains, increasing in size with MAI thickness and on annealing from 0 to 40 min and decreasing at 80 min. The film with 300 nm MAI thickness annealed for 40 min showed the strongest PL intensity suggesting reduced carrier recombination losses. Trap densities reduced with annealing time and MAI thickness due to improvements in films' crystallinity, grain sizes and reduced grain boundaries which act as carrier trapping sites. Hence, films prepared through SPVD, exhibit excellent structural, optical, and morphological properties, suitable for photovoltaic applications.

Unveiling the GeI2‐Assisted Oriented Growth of Perovskite Crystallite for High‐Performance Flexible Sn Perovskite Solar Cells

Tin perovskites are emerging as promising alternatives to their lead‐based counterparts for high‐performance and flexible perovskite solar cells. However, their rapid crystallization often leads to inadequate film quality and poor device performance. In this study, the role of GeI2 as an additive is investigated for controlling the nucleation and crystallization processes of formamidinium tin triiodide (FASnI3). The findings reveal the preferential formation of a Ge‐rich layer at the bottom of the perovskite film upon the introduction of GeI2. It is proposed that the initial formation of the Ge complex acts as a crystallization regulator, promoting oriented growth of subsequent FASnI3 crystals and enhancing overall crystallinity. Through the incorporation of an optimal amount of GeI2, flexible Sn perovskite solar cells with an efficiency of 10.8% were achieved. Furthermore, it was observed that the GeI2 additive ensures a remarkable shelf‐life for the devices, with the rigid cells retaining 91% of their initial performance after more than 13 800 h of storage in an N2 gas environment. This study elucidates the mechanistic role of GeI2 in regulating the nucleation and crystallization process of tin perovskites, providing valuable insights into the significance of additive engineering for the development of high‐performance flexible tin perovskite solar cells.

Controlling structural, electronic and optical properties of cubic FASnI3 perovskites using biaxial strains in the presence of spin orbit coupling: A DFT analysis

There is a significant research focus on the utilization of organic-inorganic hybrid perovskite materials in the field of photovoltaics. The remarkable electronic and optical characteristics of organic-inorganic hybrid perovskites are prevalent in solar applications. In this study, the first-principles density functional theory (DFT) was used to investigate how strains affect the structural, electronic, and optical properties of the formamidinium tin tri-iodide (hereafter FASnI3) perovskite structure. The band structure analysis revealed that FASnI3 possesses semiconductor properties. A direct bandgap of 0.96 eV was found at the R-point for unstrained planar FASnI3 structure. The bandgap was reduced when compressive strains were applied. In contrast, the bandgap attained a higher value due to the increased tensile strains. Moreover, the optical properties, such as absorption coefficient, dielectric function and electron loss function, showed that FASnI3 structures have good photo-absorption ability. The dielectric constant exhibited a redshift in its peaks as the compressive strains were increased. However, the dielectric peaks exhibited a blueshift when subjected to the tensile strains. Additionally, for a deeper understanding of the band structure, the effect of spin-orbit coupling (SOC) was considered. The band gap of the FASnI3 perovskite structure was 0.75 eV when the SOC effect was considered. The strain is a crucial factor to consider for optimizing the performance of FASnI3 perovskite structure for their applications in optoelectronic devices.

Performance optimization of MASnI3 perovskite solar cells: Insights into device architecture

Recent research has focused an extensive amount of attention on the lead-free substance lead-free methylammonium tin(Sn) tri-iodide (MASnI3), which has emerged as a highly potential absorber layer in the structure of the device. Because it has a larger visible absorption spectrum and a shorter band gap of 1.3 eV than the lead halide perovskite, MASnI3 is a potential alternative to MAPbX3. Through numerical simulation, the different parameters on the device performances are fully investigated. We achieved an open-circuit voltage (Voc) of 0.93 V, a short-circuit current density (Jsc) of 22.20 mA/cm2, a fill factor (FF) of 78.81 %, and a power conversion efficiency (PCE) of 16.39 % using the optimised conditions. It demonstrates the huge potential of recently created lead-free perovskite solar cells and opens up a large dimension of opportunities for the creation of novel perovskite solar cells with a variety of photovoltaic applications. The amalgamation of the Tungsten Disulfide (WS2) material layer between the electron transport layer (ETL) and the absorber layer raised the device module's power conversion efficiency to 20.36 %.

Cation Influence on Hot-Carrier Relaxation in Tin Triiodide Perovskite Thin Films.

Slow hot-carrier cooling may potentially allow overcoming the maximum achievable power conversion efficiency of single-junction solar cells. For formamidinium tin triiodide, an exceptional slow cooling time of a few nanoseconds was reported. However, a systematic study of the cation influence, as is present for lead compounds, is lacking. Here, we report the first comparative study on formamidinium, methylammonium, and cesium tin triiodide thin films. By investigating their photoluminescence, we observe a considerable shift of the emission peak to high energy with the increase of the excited-state population, which is more prominent in the case of the two hybrid organic-inorganic perovskites (∼45 meV vs ∼15 meV at 9 × 1017 cm-3 carrier density). The hot-carrier photoluminescence of the three tin compositions decays with a 0.6-2.8 ns time constant with slower cooling observed for the two hybrids, further indicating their importance.

Point defect-mediated hot carrier relaxation dynamics of lead-free FASnI3 perovskites.

In search of a promising optoelectronic performance, we herein investigated the hot carrier relaxation dynamics of a lead-free cubic phased bulk formamidinium tin triiodide (FASnI3) perovskite. To gain detailed theoretical insights, we should estimate the carrier relaxation dynamics of this pristine perovskite. To control the dynamics, point defects like central tin (Sn), iodine(I) anions, and formamidinium (FA) cations were introduced. With the iodine vacancy in the FASnI3 perovskite, the system seems to be unstable at room temperature, whereas the other three types of FASnI3 perovskites (pristine, Sn vacancy, and FA vacancy) are significantly stable at 300 K having semiconducting nature and excellent optical absorption in the UV-visible range. The computed electron-hole recombination time for the pristine system is 3.9 nanoseconds, which is in good agreement with the experimental investigation. The exciton relaxation processes in Sn and FA vacancy perovskites require 2.8 and 4.8 nanoseconds, respectively. These variations in the hot carrier relaxation dynamics processes are caused by the generation of significant changes in non-adiabatic coupling between energy levels, electron-phonon coupling, and quantum decoherence in different point defect analogous systems. The results presented here offer deeper insight into the temperature-dependent carrier relaxation dynamics of FASnI3 perovskites and thus open up opportunities for future exploration of their optoelectronic properties.

Unraveling the Performance of All‐Inorganic Lead‐Free CsSnI3‐Based Perovskite Photovoltaic with Graphene Oxide Hole Transport Layer

AbstractAddressing the imperative need to eliminate hazardous lead from the widely used metal halide perovskite photovoltaics (PPVs), the search for efficient and stable lead‐free perovskite alternatives remains pivotal. Herein, a performance analysis of lead‐free, all‐inorganic cesium tin triiodide (CsSnI3)‐based PPVs with a graphene oxide hole transporting layer using solar cell capacitance simulator is presented. Various parameters to optimize the PPV performance, including CsSnI3 layer thickness, defect density, interface defect, parasitic resistances, and working temperature are explored. The optimization process yielded remarkable results, with open‐circuit voltage of 0.87 V, short‐circuit current density of 32.55 mA cm−2, fill factor of 77.59%, and power conversion efficiency of 22.15%. The proposed device structure and parameters not only contribute to the advancement of these experimental works but also offer a novel strategy for the structural optimization of lead‐free PPVs, thereby paving new avenues for future research in this area.

PEDOT:PSS doping strategy of improving both interface energy level matching and photocarrier transport in FASnI3 perovskite solar cells

Tin-based perovskite solar cells (PSCs) have been the focus of substantial research globally as a promising choice for lead-free PSCs. Sn-based PSCs performance, however, the performance of PSCs is still significantly inferior to that of lead-based PSCs. The disparity between the energy band levels of the perovskite absorber and charge transport layers, as well as the chemical instability of Sn halide perovskite crystals, are the primary constraints in this regard. Herein, potassium chloride (KCl) was added to polymer poly (3,4-ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS) to improve the ability to transport holes and match energy levels. The formamidinium tin triiodide based PSCs constructed on KCl-doped PEDOT:PSS has a 5.9 % power conversion efficacy with a low hysteresis, which is comparatively higher than of the control devices (4.3 %). The improvement in photovoltaic performance has been predominantly attributed to two effects, specifically; PEDOT: PSS conductivity and hole extraction, both of which improved following KCl doping. More intriguingly, the modified device exhibit increased open-circuit voltage due to the downshift of PEDOT:PSS energy level by KCl doping. The composite hole transport layer strategy described in this paper provides a means for energy level adjustment and charge transport to enhance the performance of Sn-based PSCs.

Boosting efficiency of eco-friendly perovskite solar cell through optimization of novel charge transport layers.

Formamidinium tin triiodide (FASnI3) is a suitable candidate for the absorber layer in perovskite solar cells (PSC) because of its non-toxicity, narrow band gap, thermal stability and high carrier mobility. This study focuses on the analysis and improvement in the performance of FASnI3-based PSCs using various inorganic charge transport materials. The copper-based materials such as Cu2O, CuAlO2, CuSCN and CuSbS2 are introduced as hole transport layers due to their earth abundance, ease of manufacturing, high charge mobilities and chemical stability. Similarly, fullerene derivates (PCBM and C60) are deployed as electron transport layers due to their mechanical strength, thermal conductivity and stability. The effect of these materials on optical absorption, quantum efficiency, energy band alignment, band offsets, electric field and recombination are studied in detail. The reasons for the low performance of the cell are identified and improved through design optimization. The PSC performance is analysed in both inverted and conventional architecture. Among all the structures, the best result is achieved through ITO/CuSCN/FASnI3/C60/Al with an efficiency of 27.26%, Voc of 1.08 V, Jsc of 29.5 mAcm-2 and FF of 85.6%.

Seeking for Cost-Effective Tin Iodide Source toward Efficient Lead-Free Tin Triiodide Perovskite Solar Cells: Advances and Prospects

Tin triiodide perovskite (TTPs), as alternatives to their Pb counterparts, have shown great promise in photovoltaic application, and the power conversion efficiency (PCE) of Pb-free TTPs-based perovskite solar cells (PSCs) has recently been observed approaching 15%. Nevertheless, to realize the future commercialization of TTPs-based PSCs, it is still challenging to further improve the device performance, while the high cost of tin iodide (SnI2) source also remains a big concern. Therefore, seeking for a cost-effective SnI2 source has been one of the most important topics during the development course of TTPs-based PSCs. In this topical Review, we summarize the advanced studies focusing on developing cost-effective SnI2 sources for TTPs-based PSCs. Various SnI2 materials currently used for fabricating efficient TTPs-based PSCs are introduced, including commercial SnI2, purified commercial SnI2, and chemically synthesized SnI2. Also, the impact of different SnI2 sources on the crystallization process and properties of the TTPs films is discussed. At last, the current challenges and future prospects regarding the SnI2 source engineering of TTPs-based PSCs are provided. This Review could guide the further development of TTPs-based perovskite in the application of low-cost, efficient, and stable optoelectronic devices.

Unveiling the Linear Photogalvanic Effect in a Two-Dimensional Organic Tin Halide Perovskite: (CH3)2NH2SnI3

Hybrid organic–inorganic halide perovskites (HOIPs) with intrinsic noncentrosymmetry are an emerging class of semiconducting materials that has been revolutionizing the field of optoelectronics including second-order nonlinear optics (NLO). Following an upsurge in three-dimensional (3D) perovskites, more recently, low-dimensional perovskite materials have displayed desirable NLO responses attributed to structural diversity, strong quantum confinement, and remarkable exciton effect. Herein, using first-principles methods, we elucidate a linear photogalvanic effect (LPGE) photocurrent (shift photocurrent, SPC) with a maximum amplitude of ∼430 μAV–2 in a quasi-two-dimensional (2D) lead-free HOIP, (CH3)2NH2SnI3 (DMASnI3). The simulated SPC whose prominent peaks occur predominantly in the ultraviolet (UV) range is about 8-fold larger in magnitude compared to its 3D counterpart. From the orbital characteristics of the initial and final states, the calculated SPC is attributed to the contributions from the electronic properties of Sn and I whose p-states control the band edges. The organic-cation orientation indirectly influences the bandgap size, valence and conduction band edge behavior, as well as the position of the Fermi level, slightly altering the LPGE photocurrent spectrum. The findings of this work demonstrate the quasi-2D organic tin triiodide perovskite as a promising lead-free alternative for NLO devices.

Systematic investigation of the impact of kesterite and zinc based charge transport layers on the device performance and optoelectronic properties of ecofriendly tin (Sn) based perovskite solar cells

Methylammonium tin triiodide (MASnI3) perovskite solar cells (PSC) have gained a lot of interest due to their edge over conventional Pb-based PSC in terms of less-toxic nature, wider optical absorption range and smaller bandgap. In this work, 24 novel n-i-p heterostructures of MASnI3 PSC have been analyzed in detail with various zinc-based electron transport layers (ETL) and kesterite-based hole transport layers (HTL). The proposed device architecture (FTO/ETL/CH3NH3SnI3/HTL/Back contact) performance was first enhanced by optimizing the thickness and then by the doping concentration of each layer via SCAPS-1D simulator under AM 1.5G illumination. The energy band alignment of the different charge transport layers (CTL) with MASnI3 was analyzed in detail to understand its working principle. Moreover, the effects of optical absorption, band offsets, electric field, defect density, interface defects, temperature, rear reflective coating, and electrodes are monitored to characterize the performance of each cell structure. Among all the proposed structures, ZnO/MASnI3/CNTS based perovskite solar cell performed outstandingly well with Jsc of 29.44 mA cm−2, Voc of 1.12 V, FF of 88.82 %, and PCE of 29.24 %. These simulations provided important insights into the mechanism of carrier transport and the factors affecting the performance of solar cells. The results in this paper will help the research community in fabricating highly efficient eco-friendly solar cells.

Highly Stable n–i–p Structured Formamidinium Tin Triiodide Solar Cells through the Stabilization of Surface Sn2+ Cations

AbstractImproving the performance, reproducibility, and stability of Sn‐based perovskite solar cells (PSCs) with n–i–p structures is an important challenge. Spiro‐OMeTAD [2,2′,7,7′‐tetrakis(N,N‐di‐p‐methoxyphenyl‐amine)9,9′‐spirobifluorene], a hole transporting material (HTM) with n–i–p structure, requires the oxygen exposure after addition of Li‐TFSI [Lithium bis(trifluoromethanesulfonyl)imide] as a dopant to increase the hole concentration. In Sn‐based PSC, Sn2+ is easily oxidized to Sn4+ under such a condition, resulting in a sharp decrease in efficiency. Herein, a formamidinium tin triiodide (FASnI3)‐based PSCs fabricated using DPI‐TPFB [4‐Isopropyl‐4′‐methyldiphenyliodonium tetrakis(pentafluorophenyl)borate] instead of Li‐TFSI are reported as a dopant in Spiro‐OMeTAD. The DPI‐TPFB enables the fabrication of PSCs with an efficiency of up to 10.9%, the highest among FASnI3‐based PSCs with n–i–p structures. Moreover, ≈80% of the initial efficiency is maintained even after 1,597 h under maximum power point tracking conditions. In particular, the encapsulated device does not show any decrease in efficiency even after holding for 50 h in the 85 °C/85% RH condition. The high efficiency and excellent stability of PSCs prepared by doping with DPI‐TPFB are attributed to not only increasing electrical conductivity by acting as a Lewis acid, but also stabilizing Sn2+ through coordination with Sn2+ on the surface of FASnI3.

Single‐Crystal Nanowire Cesium Tin Triiodide Perovskite Solar Cell

This work reports for the first time a highly efficient single-crystal cesium tin triiodide (CsSnI3 ) perovskite nanowire solar cell. With a perfect lattice structure, low carrier trap density (≈5×1010 cm-3 ), long carrier lifetime (46.7ns), and excellent carrier mobility (>600 cm2 V-1 s-1 ), single-crystal CsSnI3 perovskite nanowires enable a very attractive feature for flexible perovskite photovoltaics to power active micro-scale electronic devices. Using CsSnI3 single-crystal nanowire in conjunction with highly conductive wide bandgap semiconductors as front-surface-field layers, an unprecedented efficiency of 11.7% under AM 1.5G illumination is achieved. This work demonstrates the feasibility of all-inorganic tin-based perovskite solar cells via crystallinity and device-structure improvement for the high-performance, and thus paves the way for the energy supply to flexible wearable devices in the future.

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.

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.

Three-dimensional narrow-bandgap perovskite semiconductor ferroelectric methylphosphonium tin triiodide for potential photovoltaic application.

A novel A-site three-dimensional organic-inorganic halide perovskites (3D OIHP) ferroelectric, methylphosphonium tin triiodide (MPSnI3), featuring a narrow bandgap of 1.43 eV, was synthesized. The integration of ferroelectricity with initially moderate efficiency (2.23%) may afford a promising platform to investigate the ferroelectric photovoltaic effect in organic-inorganic halide perovskite solar cells.

Eco-friendly methyl-ammonium tin-based planar p–n homojunction Perovskite solar cells: Design and performance estimation

In this study, the design and performance estimation of tin (Sn)-based planar [Formula: see text]–[Formula: see text] homojunction perovskite solar cell (PSC) have been carried out. Here, the effect of maintaining the intrinsic active layer thickness and replacing the intrinsic active perovskite [Formula: see text]-layer of a standard [Formula: see text]-[Formula: see text]-[Formula: see text] structure of lead (Pb)-free PSCs with a [Formula: see text]–[Formula: see text] homojunction is fully investigated. When the active layer is divided into a [Formula: see text]–[Formula: see text] junction layer, it increases the photo-generated electrons and holes efficiency due to the built-in electric field of the junction. Furthermore, in order to get a better insight, the effects of various technological and device dimensional parameters on the performance of the reported PSC have been studied. It has been reported that the thickness of the p-side with methyl-ammonium tin triiodide (MASnI[Formula: see text] layer must be greater than the n-side of the MASnI3 layer. Meanwhile, its acceptors concentration should be slightly lower than the donors’ concentration on the n-side of MASnI3 layer to achieve maximum power conversion efficiency (PCE). Using the optimized parameters, our design demonstrates an open-circuit voltage ([Formula: see text] of 0.89 V, short-circuit current density ([Formula: see text] of 32.36 mA/cm2, fill factor (FF) of 74.40%, and PCE of 21.46%. This advocates the huge potential and great opportunities for deploying these Pb-free PSCs for eco-friendly photovoltaic applications.