Indium Doping of Lead-Free Perovskite Cs2SnI6

Abstract

Structure and properties of an inorganic perovskite Cs 2 SnI 6 demonstrated its potential as a light-harvester or electron-hole transport material; however, its optoelectronic properties are poorer than those of lead-based perovskites. Here, we report the way of light tuning of absorption and transport properties of cesium iodostannate(IV) Cs 2 SnI 6 via partial heterovalent substitution of tin for indium. Light absorption and optical bandgaps of materials have been investigated by UV-vis absorption and photoluminescent spectroscopies. Low-temperature electron paramagnetic resonance spectroscopy was used to study the kind of paramagnetic centers in materials.

Mapping the Real-Time Vibrational Infrastructure of Cs2SnI6 Nanocrystals through Coherent Phonon Dynamics

“…The Gaussian fits for the FFT spectrum to spot the modes of vibration have been supplied in Supporting Information (Figure S5). In general, for any ordered double perovskite (A 2 BB′X 6 ) system with Fm 3̅ m space group crystallographic symmetry, factor group theory analysis predicts the following zone-centered (Γ) optical normal modes of vibration depicted by the irreducible representation , …”

The Prospects and Challenges for Ambi‐polar Vacancy‐Ordered Double‐Perovskite Cs2SnI6 Toward Realization of High‐Efficiency Air‐Stable Solar‐Cells

“…[ 15 ] Indium (upto 10 at% of dopant) is used to dope Cs 2 SnI 6 using the solid‐state reaction method to result in stable Cs 2− x Sn 1− x In x I 6−2 x and it is proposed that Sn 4+ in the host lattice is partially replaced by In 3+ which resulted in a small increase in band‐gap value from 1.27 eV (pristine) to 1.31 eV (doped). [ 92 ] A similar effort to partially replace Sn 4+ by Ga 3+ resulted in an increase of band‐gap value from 1.28 eV (pristine) to 1.35 eV (doped: 15 at% of dopant). [ 53 ] The dopant Ge 4+ in the form on GeI 4 precursor was alloyed with Cs 2 SnI 6 to form a solid solution of Cs 2 Sn 1− x Ge x I 6 and resulted in single‐phase material up to 5 mol% Ge concentration, which resulted in a very small decrease in band‐gap of 0.02 eV, compared to undoped 1.25 eV.…”

SnF2‐Doped Cs2SnI6 Ordered Vacancy Double Perovskite for Photovoltaic Applications

“…Zhang et al [64] have demonstrated ITO/CsSnI 3 /Cs 2 SnI 6 heterojunction with 1.1% PCE, and these devices retained 90% of the initial performance when exposed to ambient air for 20 h. Air-stable Cs 2 SnI 6 films with a bandgap of 1.48 eV and high absorption coefficient have been processed by oxidation of B-γ-CsSnI 3 for %1% n-i-p planar solar cells. [59] Elemental doping has been reported to tune the optoelectronic properties of Cs 2 SnI 6 , such as the incorporation of excess Cl or I to improve the stability, [65][66][67] indium-Cs 2 SnI 6 solid solution for enhanced photoluminescence (PL) emission, [68] A-site tailoring with monovalent Rb and Ag, [69] F À doping to improve film crystallinity in p-type Cs 2 SnI 6 , [70] and incorporation of Br À ions to prepare Cs 2 SnI 2 Br 4 films that have achieved PCE of 2.1%. [71] Another approach that has been adopted in several studies is to use the different molar ratios of CsI and SnI 4 to develop this perovskite composition for various optoelectronic applications.…”

“…[71] Another approach that has been adopted in several studies is to use the different molar ratios of CsI and SnI 4 to develop this perovskite composition for various optoelectronic applications. [54,60,[67][68][69][70][71][72][73][74] Our recently published numerical study suggests the PCE of Cs 2 SnI 6 can be increased to >25% by eliminating parasitic losses, optimizing band offsets, reducing mid-gap defect densities, and increasing the absorption coefficient. [53,75] Although significant progress has been made in the efficiency and stability of 2D/3D and 3D Sn(II)-based leadfree perovskite solar cells, limited information exists on Sn(IV)-based Cs 2 SnI 6 devices.…”