Deep surface passivation for efficient and hydrophobic perovskite solar cells

Abstract

CF3PEAI, an amphipathic passivation agent, can passivate multiple perovskite defects leading to high performance and stability of perovskite solar cells.

Creating a Dual‐Functional 2D Perovskite Layer at the Interface to Enhance the Performance of Flexible Perovskite Solar Cells

“…Very recently, the 4‐trifluoromethylphenylethylamine iodide (CF 3 PEAI, Figure ) or CF 3 PEAI‐based 2D layered perovskite was used to optimize the performance of PSCs on rigid substrate, exhibiting excellent effects on passivating defects and facilitating hole transfer. [ 22–24 ] Herein, efficient f‐PSCs were constructed via interface engineering of 2D/3D perovskite, i.e., the incorporation of a 2D perovskite (CF 3 PEA) 2 (FA) n −1 Pb n I 3 n +1 on top of the 3D perovskite FA 1− x MA x PbI 3 . The ultra‐thin 2D perovskite upshifted the energy level of 3D perovskite and decreased the energy gap between 3D perovskite and the hole transport layer (HTL) 2,2“,7,7”‐tetrakis‐( N , N ‐di(4‐methoxyphenyl‐amino)‐9,9'‐spirobi‐fluorene (Spiro‐OMeTAD), which facilitated the hole transfer due to the reduced energy barriers and charge extraction losses at the interface.…”

A Special Additive Enables All Cations and Anions Passivation for Stable Perovskite Solar Cells with Efficiency over 23%

“…Figure 3c shows the 1 H, 19 F, and 11 B NMR patterns of the pure BBF and PbI 2 -BBF composite, respectively. All the characteristic 1 H, 19 F, and 11 B peaks of BFF in PbI 2 -BBF composite show an obvious shift to higher δ value in comparison to pure BBF. The shift of 1 H is obvious in the magnified spectra in Fig.…”

“…Meanwhile, the volatile component of MA + cations tends to escape from FAMAPbI 3 perovskite under thermal stress, which results in the formation of undercoordinated Pb 2+ deep-level defects that serving as electron traps [10]. A great many works have been found that these Pb-related defects (e.g., Pb clusters and uncoordinated Pb 2+ ) in FAMAPbI 3 PSCs lead to deterioration of not only the device PCE but also the stability [11]. Meanwhile, in FAMAPbI 3 perovskite, due to the large size of the cations, shallow iodine interstitial and vacancy defects can be generated unintentionally during thermal annealing or device measurement processes, which can lower activation energy barrier for transformation from the α phase to δ phase [12].…”

Unraveling All‐Inorganic CsPbI3 and CsPbI2Br Perovskite Thin Films Formation – Black Phase Stabilization by Cs2PbCl2I2 Addition and Flash‐Annealing

“…Elsewhere, it has been showed that a 3D CsPbI 2 Br phase encapsulated in between layers of 2D Cs 2 PbCl 2 I 2 nano‐sheets is far more stable in ambient conditions than the 3D material alone and the efficiency of such heterostructure can reach up to 16.6 % [25] . The good stability of the 2D phase against humidity and temperature, which can passivate the perovskite surface, increase hydrophobicity, hamper moisture reaction and change the film morphology is also essential for optoelectronic applications [26–28] …”