High-Stability and High-Efficiency Photovoltaic Materials Based on Functional Diamino Organic Cation Halide Hybrid Perovskite Superlattice Structures

Abstract

Organic–inorganic hybrid perovskites have become the most promising materials for the next generation of solar cells. However, the low thermal and chemical stability of these materials represented by CH3NH3PbI3 is the most challenging issue, which ultimately affects the durability of devices. Therefore, to fundamentally improve the stability of perovskite solar cells, we need to explore more stable organic–inorganic perovskite materials. Using superlattice structures is an attractive strategy to expand the perovskite family and obtain excellent optoelectronic materials. The stability and photoelectric properties of hybrid perovskites can be improved by introducing a functional diamino cation. Therefore, the superlattice structure, thermodynamic stability, electronic properties, exciton properties, power conversion efficiency, and optical absorption properties of (CsPbI3) n /PDAPbI4 (n = 1–4) and (MAPbI3) n /PDAPbI4 (n = 1–4) hybrid perovskites are calculated using the first-principles method based on density functional theory. The PDA in the superlattices is p-phenylenediamine. The results show that these superlattices show good thermodynamic stability, and these superlattices have direct band gaps and are tunable, with small effective masses of electrons and holes. By increasing the coupling effect between Pb–I inorganic layers, diamino organic cations become more conducive to the carrier migration between Pb–I inorganic layers. The charge densities of the maximum valence band state and the minimum conduction band state are distributed in different regions of the superlattice. It is shown that (MAPbI3) n /PDAPbI4 (n = 3 and 4) structures are type II superlattices and the recombination rate of electron–hole pairs is greatly reduced. These superlattices have good optical absorption characteristics and high absorption coefficients in the range of solar radiation, which can provide theoretical support for obtaining stable and efficient perovskite optoelectronic devices. The power conversion efficiencies of single-junction solar cells based on (CsPbI3)4/PDAPbI4 and (MAPbI3)4/PDAPbI4 perovskites are 22.87 and 21.02%, respectively.

Three component superlattice enhanced stability for photovoltaic applications: a first principles study

“…All of the considered superlattices had negative binding energies, indicating they are more stable than each of the perovskite structures alone and exhibit good thermodynamic stability. 26,54 It is also reflective of the suitable lattice constants match between the different perovskite compounds compromising the superlattice because lattice mismatch could destabilize the crystal structure. 55 It can be seen that according to eqn (2), the binding energies of MASnI 3 /MASnI 3 /MASnI 3 , MASnI 3 /MASnBr 3 /MASnI 3 , and MASnI 3 /MASnCl 3 /MASnI 3 are more negative compared to the other materials, indicating that these superlattices are the most stable.…”

One and Two‐Dimensional 1,4‐Xylylenediammonium (pXDA) Lead Halides: Powders and Thin Films

“…[30] Therefore, a logical solution is to combine both small and long organic cations, aiming to merge the excellent photophysical properties of the 3D perovskites with the great stability of the 2D ones, an approach which has recently been intensely studied. [16,23,[31][32][33][34][35] Among the resulting intermediate states that can be obtained following this strategy, [36] Ruddlesden-Popper [37] (RP) and Dion-Jacobson [38] (DJ) phases are those that have been more widely explored. Layered perovskites typically consist of 2D slabs of the AMX 3 type structure which are separated by interlayer species and are formulated as A' 2 A n-1 M n X 3n + 1 and A''A n-1 M n X 3n + 1 , for RP and DJ systems, respectively (where A' are monocations and A'' dication-based spacer molecules, A is a smaller organic or inorganic cation, M is a divalent metal, and X is a halogen, while n represents the number of inorganic octahedra layers, i. e., the thickness of perovskite slabs).…”

“…Worthy of note, the thermodynamic stability of the 3D perovskites, in a few cases, is dramatically lowered by accessible transformation paths to insulating materials, such as the δ‐phases of CsPbI 3 [29] and FAPbI 3 [30] . Therefore, a logical solution is to combine both small and long organic cations, aiming to merge the excellent photophysical properties of the 3D perovskites with the great stability of the 2D ones, an approach which has recently been intensely studied [16,23,31–35] …”