Pressure Effects on Lead‐Free Metal Halide Perovskites: a Route to Design Optimized Materials for Photovoltaics

Abstract

Metal halide perovskites have drawn significant attention for their promising physical properties and their possible application in solar cells and light-emitting diodes. Research and technology have made extraordinary progress in this field, but some issues are still to be tackled. In fact, most of the used materials contain lead, which is highly toxic. For this reason, many efforts have been made on substituting lead with other elements to design more environmentally friendly solar cells. However, devices based on lead-free materials still show relatively low efficiencies. Physical properties tuning of such materials, to improve their performance, can be achieved in different ways, and among them pressure can be thought of as a green method for this aim as well as a powerful technique to systematically explore structure-property relationships. The possibility of unveiling and discovering novel and appealing optical and electronic features, resulting from the application of an external pressure, can open an effective route to design more performing materials.

Pressure response of decylammonium-containing 2D iodide perovskites

“…The exploration of the effect of external pressure application on metal halide perovskites (MHPs) is a topic of continuous interest because of the relevant and in some cases impressive modulation of the optical and electronic properties that can be induced on the MHP soft lattice at relatively low-pressure regimes ( Jaffe et al., 2017 ; Li et al., 2019 ; Postorino and Malavasi, 2017 ; Shi et al., 2020 ; Szafrański and Katrusiak, 2017 ). The rich set of experimental and computational data as a function of pressure collected on 3D perovskites of general formula ABX 3 (A= methylammonium, formamidinium, cesium, etc…; B=Pb, Sn, and Ge; X= Cl, Br, and I) allowed to highlight and define several common trends in the pressure-response of, for example, band gap and carrier lifetime, providing a solid basis to anticipate and predict the phase stability and electronic properties changes in these phases ( Coduri et al., 2019 , 2020 ; Jaffe et al., 2017 ; Li et al., 2019 ; Morana and Malavasi, 2021 ; Postorino and Malavasi, 2017 ; Seo et al., 1998 ; Shi et al., 2020 ; Szafrański and Katrusiak, 2017 ). In addition to the fundamental research interest of pressure-induced phenomena, the information collected in situ during pressure application may be possibly used at ambient conditions in devices by a proper modulation of stress/strain phenomena ( Jiao et al., 2021 ; Zhu et al., 2019 ).…”

Enhanced Structural Stability and Pressure‐Induced Photoconductivity in Two‐Dimensional Hybrid Perovskite (C6H5CH2NH3)2CuBr4

“…Previous studies found that high pressure techniques can be employed as one feasible and clear method to effectively tailor the crystal structures and physical properties of the 2D hybrid perovskites. [20][21][22][23][24][25][26] Karunadasa et al found that the band gap of (C 2 H 8 ClN) 2 CuBr 4 is tunable in the range 1.7-0.3 eV at pressures up to 0-65 GPa and its electrical conductivity can be successfully improved to 0.17 S cm À 1 at 59 GPa. [27] Band gap narrowing from 2.45 to 2.05 eV was also found in the [NH 3 (CH 2 ) 4 NH 3 ]CuCl 4 system, and the two NH 3 groups within the organic long chains possess stronger hydrogen bonds, thus providing ideal protection for the 2D perovskite structure at high pressures.…”

“…Previous studies found that high pressure techniques can be employed as one feasible and clear method to effectively tailor the crystal structures and physical properties of the 2D hybrid perovskites [20–26] . Karunadasa et al.…”

PERFORMANCE SIMULATION OF ECO-FRIENDLY SOLAR CELLS BASED ONCH3NH3SnI3

“…The most widespread perovskite is СH 3 NH 3 PbI 3 , also referred to as MAPI, or a methylammonium lead triiodide. However, perovskites based on MAPI are toxic due to the presence of Pb, which may destabilise the further commercialization of this material [15]. One of the alternative perovskite materials containing tin instead of lead is methylammonium tin triiodide (СH 3 NH 3 SnI 3 or MASI).…”