Inorganic Double Perovskites Research Articles

First-principles investigation of structural, electronic, optical and thermoelectric performance of stable inorganic double perovskites A2AlAgBr6 (A=K, Rb, Cs) for energy harvesting

In this work, the structural, electronic, optical and thermoelectric properties of Cs2AlAgBr6, K2AlAgBr6 and Rb2AlAgBr6 have been investigated using WIEN2k code. All the three double perovskites show stability. The stability is confirmed by calculating their formation energy, tolerance factor and molecular dynamic simulations. The electronic properties revealed the understudy compounds as semiconductors of direct band gap of 2.62, 2.61 and 2.59 eV for Cs2AlAgBr6, K2AlAgBr6 and Rb2AlAgBr6, respectively. The absorption band of our compounds is mostly in the ultraviolet energy range which is particularly significant for optoelectronic devices. The studied double perovskites exhibit a large Seebeck coefficient and electrical conductivity, which is significant for the high figure of merit. These properties make them particularly suitable for thermoelectric (TE) devices and other photovoltaic applications, as their high figure of merit at low temperatures opens up new possibilities for these materials.

Study of Mechanical, Optoelectronic, and thermoelectric aspects of lithium-based double perovskites Li2AgSbX6 (X=Cl, Br, I) for energy harvesting applications

Inorganic double perovskites appear to be incredible materials for renewable energy purposes, particularly in thermoelectric generators and solar cells. This article systematically examined the stability and various characteristics, including mechanical, thermodynamic, optical, and transport features of Li2AgSbX6 (X=Cl, Br, I), based on density functional theory (DFT) using Wien2k. The finding of formation energy is used to ensure thermodynamic strength and evaluate the tolerance factor for their structural integrity. Mechanical stability is verified by fulfilling the Born criteria involving elastic constants. The directional lattice conductivity and Debye temperature have been assessed using Navier’s velocities. The distinctive optoelectronic characteristics have been explored by adjusting the band gap from 1.40 to 0.49 eV through the varying halide ions (from Cl to I). We also examined various optical features such as absorption bands, refraction, light energy dispersion, and optical loss of the investigated materials. Key thermoelectric characteristics, including the Seebeck effect, conductivities, and performance, have been analyzed across temperatures ranging from 200 to 600 K. The high figure of merit and minimal lattice vibration at room temperature make Li2AgSbX6, double perovskites (DPs), promising for thermoelectric applications.

Exploring temperature sensing characteristics in Yb3+/Er3+ co-doped Ba2SrWO6 double perovskites

All inorganic double perovskites have been adopted as photo-luminescent hosts due to their high stability, absorption coefficient and carrier mobility. Various photo-luminescent properties are being investigated in double perovskites including infrared emitting, upconverting, afterglowing, temperature sensing and so on. Taking advantage of the Boltzmann distributed energy levels, erbium ions are gifted as spectral temperature sensing centers. Here, we synthesized Er3+ doped monoclinic Ba2SrWO6 (BSWO) double perovskites and carried out a series of examinations for their upconverting as well as temperature sensing characteristics. Upon 980 and 1550 nm excitation, the upconversion processes are determined by the relationship between emission intensities against excitation powers. The optical temperature sensitivities are evaluated by exploiting fluorescence intensity ratio (FIR) and lifetime, where the maximum values for FIR and lifetime sensitivities are 14.3 × 10−3 and 2.2 × 10−3 K−1 respectively, suggesting that Er3+ doped double perovskites hold great potential for the development of novel optical temperature sensing materials.

Study of mechanical, thermodynamic, thermoelectric, and optical properties of Cs2SbAuX6 (X = Cl, Br, I) for energy harvesting applications

The inorganic double perovskites (DPs) Cs2SbAuX6 (X = Cl, Br, I) are an emerging applicant for solar cells, optoelectronic, and thermoelectrics to acquire clean energy. Therefore, the present research thoroughly addresses the mechanical, thermodynamic, optical, and thermoelectric characteristics by modified Becke and Johnson potential of Trans and Balaha (TB-mBJ) and BoltzTraP code. The structural stability is narrated from the tolerance factor and thermodynamic stability by formation energy. Born criteria assure the mechanical existence of cubic structures. The Cs2SbAu(Cl/Br)6 is ductile, and Cs2SbAuI6 has brittle behavior with a metallic nature. The band structures analysis reports the narrow band gaps for Cl/Br and the zero band gap for I-based DPs. The optical properties are studied by dielectric constants, absorption bands, refractive index, and other dependent optical parameters. Lastly, thermoelectric characteristics regarding Seebeck coefficient, electrical conductivity, power factor, thermal conductivity, and figure of merit in the temperature range 200–600K are analyzed. ZT's significant value at room temperature makes them potential candidates for thermoelectric generators.

Unraveling the Role of 2D Ti3C2Tx MXene Nanosheets in Cu-Based Double Perovskite Active Layer for Enhanced Photovoltaic Performance.

Although the atmospheric stability of lead-free inorganic double perovskite (DP) solar cells (PSCs) looks promising, their further development is hampered by inadequate film quality and non-radiative carrier recombination at the interfaces. Herein, the incorporation of a newly developed intriguing class of 2D material Ti3C2Tx MXene nanosheets with the photo-absorbing Cu2AgBiI6 (CABI) active layer of a fully inorganic solar cell is reported. The highly conductive Ti3C2Tx nanosheets work as a multi-functional additive by tuning the band gap, reducing the non-radiative carrier recombination, and inhibiting carrier accumulation. In addition, the presence of Ti3C2Tx MXene increases the surface free energy of the perovskite film, which elevates the energy barrier for nucleation and realizes a highly crystalline CABI perovskite film. Primarily, the MXene modification accelerates the charge extraction and transport at the interfaces of the active layer, utilizing energy level alignment with the charge transport layers. Consequently, the photo-conversion efficiency (PCE) of the device with MXene is substantially enhanced to 1.50%. Moreover, the 2D Ti3C2Tx nanosheets increased the long-term stability of the devices by retaining 70% of the initial PCE after 1680 h. With regard to relieving the severe carrier recombination at the interfaces, this work sets a new paradigm toward imminent solar energy conversion.

Thermal, optoelectronic and thermoelectric properties of inorganic double perovskites semiconductors Cs2(Sn, Pt, Te)I6 for application as intermediate-band solar cells

First-principle calculations using the Wien2k code and the GGA-mBJ exchange potential were used in the study of the thermodynamic, dynamic, chemical and elastic stability, as well as the electronic, optical and thermoelectric properties of Cs2(Sn, Pt, Te)I6. The presence of an intermediate band in Cs2(Sn, Pt, Te)I6 semiconductors confirmed by absorption peaks appeared at photon energy corresponding to the band gap enhances the efficiency of solar cells. The ideal band gap, high dielectric constants and optimal absorption make the double perovskites under study perform well in solar cells. The calculated minimum formation energy, Helmholtz free energy and phonon modes through the first Brillouin zone for the investigated Cs2(Sn, Pt, Te)I6 family confirm their thermal, thermodynamic and dynamic stability. The acoustic phonon contribution modes come from the Cs-6s and I-5p electrons, while the Pt-6s, Sn-5p, Te-5p and I-5p electrons participate in the optical phonon modes. The narrowness of the upper valence band and the band gap in the visible region for Cs2PtI6 advantage this double perovskite in energy harvesting. The geometric Goldschmidt tolerance factor value between 0.8 and 1.0 and octahedral factor 0.41 indicate that Cs2SnI6 double perovskite is more stable.

Predicting the band gap of lead-free inorganic double perovskites using modified parallel residual network

The rapid and precise screening of appropriate inorganic perovskite materials poses a formidable challenge in the field of materials science. Traditional methods for material screening are not only time-consuming but also demand a substantial workforce. In this study, we introduce a modified parallel residual network (PRN) for the purpose of predicting the band gap of lead-free inorganic double perovskite materials, utilizing the atomic composition as the input data. The predictive performance of PRN is assessed using root mean square error (RMSE) and Pearson correlation coefficient ( r) as evaluation metrics. The PRN model yields a band gap prediction with an RMSE of 0.402 eV and an r value of 0.962, respectively. Notably, PRN outperforms various alternative models, including random forest regression (RFR), kernel ridge regression (KRR), support vector regression (SVR), extreme gradient boosting regression (XGBR), one-layer residual variant network (OLRN), and three-layer parallel residual variant network (TLPRN), clearly demonstrating its superior predictive accuracy.

Self-energy correction and numerical simulation for efficient lead-free double perovskite solar cells.

Inorganic double perovskites have garnered significant attention due to their desirable characteristics, such as low-toxicity, stability and long charge-carrier lifetimes. However, most double perovskites, especially Cs2AgBiBr6, have wide bandgaps, which limits power conversion efficiencies. In this work, through the first principles method corrected by self-energy, we investigate the mechanical, electric and optical properties of Cs2B'B''Br6 (B' = Ag, Au, Cu; B'' = Bi, Al, Sb, In). Based on performance screening, three kinds of materials with good toughness, high carrier mobility and wide visible-light absorption (around 105 cm-1) are obtained, which are compared with Cs2AgBiBr6. Meanwhile, we use a SACPS-1D simulation to design lead-free double perovskites with excellent properties suitable for photovoltaic solar cell devices, which are made into a planar perovskite heterojunction. Ultimately, the optimal structure is determined to be FTO/WS2/Cs2CuBiBr6/spiro-OMeTAD/Ag, which achieves a power conversion efficiency of 14.08%, surpassing the conventional structure efficiency of 6.1%. It provides valuable guidance for the structure design of a lead-free double perovskite device and offers new insights into the development of optoelectronic devices for solar energy utilization.

Copper Modulated Lead‐Free Cs4MnSb2Cl12 Double Perovskite Microcrystals for Photocatalytic Reduction of CO2

AbstractIn order to deal with the global energy crisis and environmental problems, reducing carbon dioxide through artificial photosynthesis has become a hot topic. Lead halide perovskite is attracted people's attention because of its excellent photoelectric properties, but the toxicity and long‐term instability prompt people to search for new photocatalysts. Herein, a series of <111> inorganic double perovskites Cs4Mn1‐xCuxSb2Cl12 microcrystals (x = 0, 0.1, 0.2, 0.3, 0.4, and 0.5) are synthesized and characterized. Among them, Cs4Mn0.7Cu0.3Sb2Cl12 microcrystals have the best photocatalytic performance, and the yields of CO and CH4 are 503.86 and 68.35 µmol g−1, respectively, after 3 h irradiation, which are the highest among pure phase perovskites reported so far. In addition, in situ Fourier transform infrared (FT‐IR) spectroscopy and electron spin resonance (ESR) spectroscopy are used to explore the mechanism of the photocatalytic reaction. The results highlight the potential of this class of materials for photocatalytic reduction reactions.

First principle insight on optoelectronic and transport characteristics of lead-free inorganic double perovskites Rb2KTlX6 (X = Cl, Br) for solar cell applications

The toxicity and instability of lead-based perovskites have been replaced with newly investigated stable lead-free inorganic perovskites. The current study included the comprehensive analysis of electronic behavior, elastic, optical, and transport characteristics of lead-free inorganic double perovskites (DPs) Rb2KTlX6 (X = Cl, Br) halides for possible uses. These physical characteristics were revealed using density functional theory (DFT) based Wien2k code. Using the energy optimization process, we have computed structural parameters comparable to existing data using generalized gradient approximation (PBEsol-GGA). In addition, the elastic parameters, formation energy (−1.94 eV and −1.39 eV), and tolerance factor (0.98 and 0.97) endorsed the cubic stability of both halides. Further, we employed modified Becke-Johnson (mBJ) potential to an accurate value of direct bandgaps of both halides reveal that changing the anions from Cl to Br leads to significant adjustment in the band gap, transitioning from the visible to the IR spectrum, with energy levels ranging from 2.08 to 1.2 eV. Our calculated results of optical parameters indicate that both halides with remarkable optoelectronic working due to low reflectivity, high optical absorption, and conductivity. The study reveals that electronic transport factors are associated with temperature due to small bandgap of the materials. The observed figure of merit near unity indicates the semiconducting behavior of these materials that can be useful in thermoelectric tools.

Prospective lead-free fluorine double perovskites Rb2B'BiF6 (B' = Ag, Cu, In): Unveiling solar cell and optoelectronic promise through ab-initio insights

This study takes a comprehensive approach to investigate the optical and transport attributes of the fourth stable double perovskites—Rb2AgBiF6, Rb2CuBiF6 and Rb2InBiF6with a focus on their potential applications in photovoltaic, optoelectronic devices and thermoelectric systems. Calculated indirect band gap values are unveiled, measuring 2.07/1.90, 1.10/1.03 eV for Rb2AgBiF6 and Rb2CuBiF6 using PBE-GGA/LDA respectively. While for Rb2InBiF6 a direct band gap of 1.0/0.7 eV was found. We meticulously discuss optical features, encompassing dielectric constants, absorption coefficients, refractive indices, and reflectivity. Notably, prominent absorption peaks occur within the visible and ultraviolet spectrum across the three compounds, solidifying their suitability for solar cells and optoelectronic endeavors. Electron transport properties are scrutinized, encompassing electrical conductivity, thermal conductivity, Seebeck coefficient, and the figure of merit ZT. Utilizing the BoltzTraP code, these calculations span temperatures from 50 K to 1200 K. Our analysis of transport properties foresees the p-type semiconducting nature of the inorganic double perovskites Rb2B'BiF6 (B' = Ag, Cu, In), adding depth to the characterization of their transport behavior. These findings hold significance for their potential deployment in various photovoltaic, optoelectronic and thermoelectric applications, underlining their potential for advancing diverse technological landscapes.

A2LiGaI6 (A = Cs, Rb): New lead-free and direct bandgap halide double perovskites for IR application

Recently, all inorganic double perovskites have drawn a lot of interest as promising solar materials. The optical, structural, thermoelectric, electronic, and mechanical properties of double halide perovskites A2LiGaI6 (A = Cs, Rb) are explored via first-principles calculations with the WIEN2k code, using GGA PBEsol and TB-mBJ potentials. The majority of perovskite materials utilized in the highest-performing solar cells have bandgaps ranging between 1.48 and 1.62 eV. The compounds A2LiGaI6 (A = Cs, Rb) have a direct bandgap of 1.51 eV and 1.55 eV, respectively, and are expected to be useful in solar cells. The optical study shows that there are large absorption bands in the visible region, as determined by the dielectric constant, absorption, and other dependent factors. Their potential for use in solar cells is increased by their absorption in the visible part. The BoltzTraP code has been used to perform thermoelectric studies to assess the electrical, thermal conductivities, and Seebeck coefficient. They are important for construction of thermoelectric generators that harvest heat energy because of their high figure of merit and incredibly low thermal conductivity of lattice at ambient temperature. Furthermore, by examining the spectroscopic limit maximum efficiency, up to 30 % efficiency is predicted for both compositions, which paves the way for the applicability of them in solar energy conversion.

Computational analysis of hybrid double perovskite materials and their potential in photovoltaic and thermoelectric applications

Hybrid double perovskites are promising for use in next-generation solar cells. The priority is to address their critical problems and gain insight into their operation. The density functional theory is employed to obtain the mechanical, electronic, and optical properties of organic–inorganic double perovskites based on aluminum and gallium. The results revealed that the double perovskite materials are stable, as confirmed by calculating the formation energy and the elastic constant. Moreover, when using the TB-mBJ functional, the electronic properties obtained indicate that the direct band gap values are 1.39 eV and 2.72 eV for (NH4)2AgGaBr6 and (NH4)2AgAlBr6, respectively. Additionally, because of the direct band nature of (NH4)2Ag(Al/Ga)Br6, they exhibit excellent optical properties, including a high order absorption coefficient of 105 cm−1 and low reflectivity, making them useful for multiple optoelectronic applications outside of photovoltaics. Calculations of SLME revealed that (NH4)2AgGaBr6 and (NH4)2AgAlBr6 achieve single-layer efficiency of 32.87% and 8.36% respectively, emphasizing their viability for future applications. The results of the thermoelectric analysis suggest that these compounds have a promising potential for use in transport applications, as they demonstrate a higher figure of merit (ZT) compared to other compounds. Specifically, (NH4)2AgAlBr6 has a ZT value of 0.734, while (NH4)2AgGaBr6 has a ZT value of 0.737.

Study of inorganic double perovskites Cs2RbZI6 (Z = Ga, In) as energy harvesting aspirant: a DFT approach

Study of inorganic double perovskites Cs2RbZI6 (Z = Ga, In) as energy harvesting aspirant: a DFT approach

First-principles calculations to investigate mechanical, thermoelectric and optical performance of inorganic double perovskites Rb2CuBiX6 (X = Cl, Br, I) for energy harvesting

The double perovskites Rb2CuBiX6 (X = Cl, Br, I) are studied for thermoelectric and optoelectronic applications for energy harvesting. The confirmation of thermodynamic constancy has been reported by formation energy and tolerance factor by structural stability. The lattice constant increases and bulk modulus decreases by changing the halogen ions (Cl, Br, I). The ductile behavior, large Debye and Kelvin temperatures along hardness and ultralow values of lattice thermal conductivity are calculated from elastic constants. The TB-mBJ potential has been used to modify the band gaps from 1.18 to 0.68 eV by shifting of halogen ions Cl to I. The optical characteristics are analyzed by absorption, dispersion, refractive index, and reflection of light energy. In addition to above, the transport characteristics are analyzed by Seeback coefficient, electronic and thermal conductivities. The figure of merit calculations shows the excellent thermoelectric performance of studied DPs.

Opto-electronic and thermoelectric properties of free-lead inorganic double perovskites Rb/Cs2ScAuI6 for energy devices

Nowadays, the search for renewable and sustainable energies is a global concern worldwide. In this regard, extensive studies are devoted to inorganic perovskites; nonetheless, the latter suffers from several drawbacks, such as lead toxicity. In this paper, structural stability, optoelectronics and thermoelectric characteristics of double perovskites (DPs) Rb/Cs2ScAuI6 have been systematically explained. The phonon dispersion is evaluated for structural existence, and the formation energy is determined to confirm thermodynamic stability. In addition, the elastic constants fulfilled the Born stability criteria, and Pugh’s ratio (B/G) confirms the ductile nature of studied DPs. The obtained results for electronic characteristics of Rb/Cs2ScAuI6 using mBJ+SOC and HSE06 show that the indirect bandgap nature has bandgap values 1.40/1.95 eV and 1.36/1.90 eV, respectively. Further, optical characteristics of DPs have been investigated in terms of dielectric function up to incident photon energy 0–12 eV. Besides, the transport behavior in terms of temperature, carrier concentration, and chemical potential calculated using the BoltzTrap code indicates that both DPs low thermal conductivity, high electrical conductivity, and high Seebeck coefficient.

Morphology of highly stable lead-free hybrid organic–inorganic double perovskites (CH3NH3)2XBiCl6 (X = K, Na, Ag) for solar cell applications

Morphology of highly stable lead-free hybrid organic–inorganic double perovskites (CH3NH3)2XBiCl6 (X = K, Na, Ag) for solar cell applications

Study of optoelectronic, thermoelectric, mechanical, and thermodynamic properties of Cs2NaTlX6 (X = Cl, Br, I) for energy harvesting

The inorganic double perovskites are remarkable materials for renewable energy which can be realized through solar cells and thermoelectric generators. Here, we have comprehensively elaborated the stability, mechanical, thermodynamic, optical and transport characteristics. The formation energy is computed to ensure thermodynamic validity and the tolerance factor is assessed for structural existence. The elastic constants satisfied the Born criteria and mechanical stability. Naviera's velocities have been used to study the Debye temperature and directional lattice conductivity. Modifying the band gap from 3.1 to 0.58 eV by halide ions (Cl to I) probes the distinct optoelectronic characteristics. Absorption bands, dispersion of light energy, refraction, and optical loss explain the optical characteristics. In addition, the above thermoelectric factors like conductivities, Seebeck effect, and performance are studied in the temperature range of 100–600 K. Large figure of merit and extremely low lattice vibration at room temperature indicate their significance for thermoelectric devices.

First-principles calculations to investigate mechanical, thermoelectric and optical performance of inorganic double perovskites Rb2AgAlZ6 (Z = Br, I) for energy harvesting

The clean and green energy is a merging technology of advanced era to achieve the demands of energy requirements. For this purpose, the double perovskites Rb2AgAlZ6 (Z = Br, I) are explored comprehensively in terms of optical, mechanical, thermoelectric, and thermodynamic characteristics. The stability of structures, elastic and thermodynamic have been ensured through tolerance factor, Born Criteria, and formation energy. The elastic constants of cubic symmetry are analyzed to distinguish ductile/brittle nature, anisotropy, Harness, minimum lattice thermal, conductivity, melting and Debye temperatures. The anions (Br, I) modified the band gaps (2.60, 1.08) eV which turned the absorption of light energy from ultraviolet to visible portion of spectrum. The absorption band of Rb2AgAsI6 in the energy range 1.7eV–3.4 eV is particularly significant for solar cells. The large Seebeck coefficient, and electrical conductivity while particularly low lattice thermal conductivity has been increased the figure of merit. The large figure of at low temperature open the new finding roots for realization of these DPs for thermoelectric and other energy applications.

New investigated lead free double perovskite materials Rb2LiBiX6 (X= Cl, F, Br, I) for optoelectronics and solar cell applications via first principle calculations

The physical properties of cubic inorganic double perovskites Rb2LiBiX6 (X = Cl, F, Br, I) were investigated by using density functional theory (DFT) based on Wien2K code. The structural parameters obtained are calculated by using Murnaghan equation of state and Chapin's method. The results found by exploring the mechanical properties and the enthalpy of formation of the materials ensuring the stability of the materials. This research expansively investigates optical and transport properties of the fourth double perovskite Rb2LiBiCl6, Rb2LiBiF6, Rb2LiBiBr6 and Rb2LiBiI6 for optoelectronics devices and thermoelectric applications. The calculated indirect band gap values are 4.96, 3.62, 2.93 and 2.00 eV for Rb2TeF/Cl/Br/I6 respectively. Optical properties are discussed in terms of dielectric constants, absorption coefficient, refractive index and reflectivity. Utmost peaks absorption occurred in the ultraviolet region for all compounds, which confirm their useful employment for optoelectronic applications. The electron transport properties are studied by electrical conductivity, thermal conductivity, Seebeck coefficient, and figure of merit. ZT. The calculations are performed versus the temperature in the range of 100–1200 K using BoltzTraP code. The p-type semiconducting character of the inorganic double perovskites Rb2LiBiX6 (X = Cl, F, Br, I) has been forecast by transport properties analysis.