Engineering of Perovskite Materials Based on Formamidinium and Cesium Hybridization for High-Efficiency Solar Cells

Abstract

Engineering the chemical composition of inorganic–organic hybrid perovskite materials is an effective strategy to boost the performance and operational stability of perovskite solar cells (PSCs). Among the diverse family of ABX3 perovskites, methylammonium-free mixed A-site cation Cs x FA1–x PbI3 perovskites appear as attractive light-absorber materials because of their optimum band gap, superior optoelectronic property, and good thermal stability. Here, we develop a simple and very effective one-step solution method for the preparation of high-quality (Cs) x (FA)1–x PbI3 perovskite films upon the addition of excess CsCl to the FAPbI3 precursor solution. It is found that the addition of CsCl as a source of Cs cation instead of relevant addition of CsI to the parent perovskite solution increases effectively the grain size and film quality leading to improved charge mobility, reduced carrier recombination, and long carrier lifetime. The resultant mesoscopic perovskite devices exhibit a maximum efficiency of 20.60% with a stabilized power conversion efficiency of 19.85% and lower hysteresis compared to the reference device. This performance is among the highest reported for PSC devices incorporating mixed cation (Cs) x (FA)1–x PbI3 perovskites.

Carbon-based materials for stable, cheaper and large-scale processable perovskite solar cells

“…A suitable strategy to further enhance PSC efficiency is the replacement of a methylammonium (MA) cation 98 with 5-amino valeric acid (5-AVA) 99 or formamidinium (HC(NH 2 ) 2 + , FA). 100,101 When 5-AVA is added in the precursor solution, it replaces the MA cation in the cuboctahedral site of MAPbI 3 . 5-AVA templates the crystallization of the perovskite in the pores of mesoporous TiO 2 , providing a lower defect concentration, 99 while its -COOH and -NH 2 groups interact with TiO 2 through hydrogen bonding, ensuring a better interfacial contact with the anode.…”

Efficient Passivation with Lead Pyridine‐2‐Carboxylic for High‐Performance and Stable Perovskite Solar Cells

“…Despite the impressive high efficiency, the stability of PSCs lags far behind the requirement for future commercialization. [16][17][18][19][20] However, there is still great challenge to obtain long-term stability and further investigation is urgent. [3,9,10] Efforts have been carried out to improve the stability of PSCs such as solvent engineering, [11][12][13] interface engineering, [14,15] composition engineering, and encapsulation.…”

Highly efficient and stable inverted perovskite solar cells using down-shifting quantum dots as a light management layer and moisture-assisted film growth

“…[4][5][6][7][8][9] Besides the further improvement of photovoltaic performance, long-term device stability is a key challenge for the commercialization of PSCs. 10,11 The main reported strategies to improve stability include compositional engineering, [12][13][14] interface modication, 15,16 passivation techniques, 17,18 using water-repellent materials [19][20][21][22] and device packaging via encapsulation methods. 23,24 These techniques enhance the device performance and stability by reducing the recombination sites and improving the quality of PSCs.…”