Ag/In lead‐free double perovskites

Abstract

Lead‐free Cs2AgInCl6 and Cs2AgInBr6 double perovskites are studied by a combination of advanced ab‐initio calculations and photoluminescence experiments. We show that they are insulators with direct band gaps of 2.53 and 1.17 eV, respectively; most importantly, they are characterized by unusually low absorption rates in a ~1 eV wide energy region above the band gap, caused by rather peculiar electronic properties. Consequently, this low absorption conveys very long recombination lifetimes, up to milliseconds at low temperature. Our theoretical analysis suggests that such materials can achieve a good compromise between photoconversion efficiency (above 10%) and visible transmittance (above 30%), which makes them potentially suited for lead‐free semitransparent solar cell applications.

Fundamentals of tin iodide perovskites: a promising route to highly efficient, lead-free solar cells

“…In this work we use a method, the variational pseudo self-interaction correction approach (VPSIC), 55 which over the years has demonstrated to satisfy both accuracy and computational feasibility for large-size systems such as superlattices [56][57][58] and surfaces, 59 and was recently applied to Ge-based hybrid perovskites 60 and In/Ag double perovskites. 61 The VPSIC removes the main DFT deciency, namely the electronic self-interaction (SI) present in the single particle potential. The SI is a blessing from computational viewpoint, since it causes the electronic potential to be local, and is at the root of the powerful simplicity of the DFT approach.…”

A Perspective on the Commercial Viability of Perovskite Solar Cells

“…Long photoluminescence lifetime (660 ns) was reported for Cs 2 AgBiX 6 (where X = Br or Cl) due to its indirect bandgap. [ 476,479–481 ] However, the poor electron diffusion coefficient (30 nm) was also observed in this material due to the high density of electron traps, justifying the poor photocurrent. [ 480,482 ] The deep energy trap states are attributed to D electronic dimensionality arising from the separation of M (I) X 6 octahedra by the B (III) X 6 octahedra.…”

“…[ 476,479–481 ] However, the poor electron diffusion coefficient (30 nm) was also observed in this material due to the high density of electron traps, justifying the poor photocurrent. [ 480,482 ] The deep energy trap states are attributed to D electronic dimensionality arising from the separation of M (I) X 6 octahedra by the B (III) X 6 octahedra. [ 465 ] This statement was further verified through simulation of the 3D structural dimension Cs 2 SrPbI 6 , where optoelectronic properties of 0D Cs 4 PbI 6 were observed, [ 483 ] concluding that the carrier in double perovskite is indeed confined electronically.…”

Multifunctional Crosslinking‐Enabled Strain‐Regulating Crystallization for Stable, Efficient α‐FAPbI3‐Based Perovskite Solar Cells

“…[1][2][3][4][5][6][7] Great advancement has been achieved in the area of PSCs, where the power conversion efficiency (PCE) of PSCs has raised from 3.8% [8] to a certified 25.5% PCE in less than 13 years. [9] Formamidinium lead triiodide (FAPbI 3 ) with a narrower bandgap and thus greater light spectral response [10][11][12][13][14][15][16] has attracted wide interest and become the ideal light absorber material for PSCs. However, a higher annealing temperature is necessary for converting the δ-FAPbI 3 to α-FAPbI 3 (≈150 °C) compared with the MAPbI 3 case (≈100 °C).…”