Impact Factor:0.0
DOI number:10.1039/c8tc03926g
Journal:J. Mater. Chem. C
Abstract:As a newly-rising member in the perovskite family of solar cell absorbers, the lead-free halide double perovskites Cs2M+M3+X6 (X = Cl, Br, I), with suitable bandgaps in the visible-light region and intrinsic thermodynamic stability, pave a new way in designing environmentally friendly perovskite solar cell devices. Here, for the first time, we optimize 24 kinds of layered Ruddlesden–Popper (RP) type n = 1–3 Csn+1Mn/2+Mn/23+X3n+1 (M+: In+, Cu+, Ag+, Au+; M3+: Bi3+, Sb3+) and investigate their electronic, optical and transport properties based on powerful first-principles and GW-BSE calculations. Surprisingly, we find that Cs4In3/2Sb3/2I10 (n = 3) has a direct bandgap of 1.29 eV, a very suitable value for visible-light absorption and emission. In order to modulate the bandgap and charge distribution, we further construct 7 two-dimensional halide double perovskite heterostructures with direct bandgaps and type-II band alignment, leading to a remarkable spatial separation of photo-generated carriers and a noticeable reduction of the carrier recombination rate, which is beneficial for photovoltaic devices. Typically, the Cs4In3/2Sb3/2Cl10/Cs2Cu1/2Bi1/2Cl4 heterostructure has a direct bandgap of 1.65 eV with a great electron–hole spatial separation. Both the different layered CsInSbI perovskites and CsInSbCl/CsCuBiCl-based heterostructures have an ultrahigh absorption coefficient of ∼105 cm−1 in the visible-light region, which is comparable with bulk MAPbI3. Moreover, their electron and hole mobilities are three/four orders of magnitude larger than MAPbI3 up to 102–103 cm2 V−1 s−1. The novel properties of the suitable bandgap, spatial separation of carriers, excellent absorption coefficient and extremely high carrier mobility suggest that the 2D layered RP-type CsInSbI- and CsInSbCl/CsCuBiCl-based perovskites have great potential as promising lead-free solar cell absorbers and solid-state-lighting materials.
Indexed by:Journal paper
Discipline:Natural Science
First-Level Discipline:Physics
Volume:6
Page Number:11575-11586
Translation or Not:no
Included Journals:SCI
Date of Publication:2018-10-10