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Perovskite solar cells have become the most promising third-generation solar cells because of their superior physical–chemical properties and high photoelectric conversion efficiency. However, the current obstacles to commercialization of perovskite solar cells are their poor stability and harmful elements. How to find high-efficiency, high-stability and non-toxic perovskite materials from thousands of possible perovskite crystals is the key to solve this problem. In this paper, the inorganic halide double perovskite A2BX6 and its crystal structure are considered, and the data mining algorithm in informatics is introduced into the high-throughput computing data to analyze various elements in nature to study the perovskite materials that can meet the requirements of high performance. The photoelectric conversion properties and stability of 42 inorganic double perovskite materials are studied based on density functional theory (DFT). The results show that the tolerance factors of 39 crystals are between 0.8 and 1.10, indicating that these crystals have stable perovskite structure. In addition, the dielectric function, PDOS, elastic modulus, shear modulus and poison's ratio of these crystals are analyzed. According to the above theoretical simulation results, three candidate materials for ideal light absorption are presented. This can provide a theoretical basis for the industrial application of perovskite solar cells. [ABSTRACT FROM AUTHOR]

The effect of lithium doping on novel double perovskite materials for hydrogen storage has been investigated through first-principles calculation. The lithium doping would cause phase change due to different crystal symmetry. Based on tolerance factors, cohesive energy and Born-Huang criteria, the materials are all stable. The analysis of hydrogen storage properties indicates that lithium doping can both improve the gravimetric storage capacity to 4.41% and 5.08%, and decrease the desorption temperature to 348.7 K and 325.0 K for K 2 LiScH 6 and K 2 LiAlH 6 , respectively. And to a certain extent, the introduction of lithium improves the optoelectronic properties especially the photoresponse in ultraviolet region, which demonstrates the applicable potential in photocatalysis. The results are consistent with the wide bandgap values. Our study provides some reference for further experimental studies of double perovskites in hydrogen storage materials. • Lithium is introduced into double perovskites to improve hydrogen storage characteristics. • These materials exhibit an optimal storage capacity of 5.08% and desorption temperature of 325.0 K. • The variations of accurate optoelectronic property are obtained by hybrid HSE06 functional. [ABSTRACT FROM AUTHOR]

The physical properties of three potential colbat-containing perovskites are studied through first principles calculation. The structural analysis reveals that the Cs 2 InCoI 6 and Cs 2 AgCoI 6 are ductile and potential in flexible devices. The negative formation energies indicate that all these perovskite syntheses are practicable in experiment. However, the results of tolerance factors and phonon spectra are presented against the structural dynamic stability of pure cubic phase of Cs 2 TlCoI 6 and Cs 2 AgCoI 6 and there may be lattice distortion. The band gaps of Cs 2 InCoI 6 , Cs 2 TlCoI 6 and Cs 2 AgCoI 6 are 0.833 eV, 1.713 eV and 0.783 eV, respectively, all values are within the ideal range for semiconductors that applied in optoelectronic devices. They all exhibit broad-spectrum light absorption in ultraviolet and visible region, and the absorption coefficient of Cs 2 InCoI 6 even maintains a value above 10000 cm−1 at wavelength of 1400 nm. Among them, Cs 2 InCoI 6 perovskite has direct band structure, smaller carrier effective mass than that of CsPbI 3 and broad solar absorption characteristics, which is considered as a promising candidate material for optoelectronic devices. • The physical properties of three novel cobalt perovskites are studied. • Cs 2 TlCoI 6 is found to be stable in tetragonal rather than cubic phase thus a phase transition may take place. • Cubic Cs 2 InCoI 6 is found to be a stable perovskite with broadband light absorption. • Pressure-induced optical properties and structural stabilities of Cs2InCoI6 are studied. [ABSTRACT FROM AUTHOR]

The comparison study of arsenic-based double halide perovskite materials concentrated on the physical properties is initiated based on first principle. The structure stability is confirmed by the tolerance factor, formation energy and elastic constant. The materials are ductile and ionic compounds through elastic properties. The range of band gap is from 0.882eV to 2.125eV, close to the recommended values for optoelectronic and photovoltaic application. The halogen atoms have great effects on electronic band structures while alkali metal does rarely. All small effective masses for the studied materials indicate high mobilities, favorable for carrier transport. The excellent light absorption properties corresponding to ultraviolet–visible–infrared region reveal great applicable potential for solar energy utilization. Among these materials, K2AgAsBr 6 is the most suitable for use as a solar cell material and photocatalytic material because it has an ideal band gap value, high dielectric constant and good optical absorption properties. [Display omitted] • The arsenic-based double perovskite A 2 AgAsX 6 (A ​= ​K, Rb, Cs; X ​= ​Cl, Br, I) possess ideal band gaps from 0.882eV to 2.125eV. • Their high absorption coefficients, which correspond to the solar spectrum, indicate effective utilization of solar energy. • K 2 AgAsBr 6 is the best candidate for photovoltaic application among the studied materials. [ABSTRACT FROM AUTHOR]

[Display omitted] • The materials are stable double perovskites by tolerance factor and formation energy. • The studied materials are all direct and quasi-direct semiconductors. • Tl 2 PdBr 6 is regarded as a potential candidate for single junction solar absorber. The structural stability, energy band and photoelectric properties of vacancy- ordered double halide perovskites A 2 BX 6 (A = In, Tl; B = Pd, Pt; X = Cl, Br, I) are studied in detail by first principles in this paper. The results show that these materials have suitable tolerance factor, negative formation energy and good phonon spectrum, which indicates that they have structural stability. These materials are all semiconductors with band gaps varying from 0.328 eV and 3.238 eV via HSE06 hybrid functional. All the materials have direct or quasi-direct band structures, which are beneficial for carrier generation. These materials have small reflectance and large absorption coefficients for visible - infrared light, especially in the ultraviolet region where the absorption coefficient is very large. The absorption coefficient of the material is obviously improved when the anion X changes from Cl to Br to I. Making a comprehensive analysis of absorption coefficient, transmittance and bandgap values, Tl 2 PdBr 6 is regarded as a potential candidate for solar absorber in single junction solar cells, while In 2 PtCl 6 and Tl 2 PtCl 6 may be applied in transparent conductor films. [ABSTRACT FROM AUTHOR]