Multifunctional Polymer Framework Modified SnO₂ Enabling a Photostable α-FAPbI₃ Perovskite Solar Cell with Efficiency Exceeding 23%

Abstract

Poly(ethylene glycol) diacrylate (PEGDA) is introduced into the SnO 2 dispersion as the polymer framework to hinder the agglomeration. The PEGDA-modified SnO 2 acted as the electron transport layer (ETL) in n-i-p structured perovskite solar cells (pero-SCs). It is demonstrated that the PEGDA plays multifunctional roles in the enhancement of photovoltaic performance and stability against illumination and humility. First, the PEGDA-modified SnO 2 ETL is more uniform, and its energy level matched well with the perovskite, which could facilitate the carrier transport and reduce the energy loss. Second, PEGDA could passivate the defects at the interface between perovskite and ETL. Eventually, a power conversion efficiency (PCE) of 23.31% is achieved for the α-FAPbI 3 based pero-SCs. Most importantly, the unencapsulated devices maintained more than 90% of the initial PCE after 850 h continuous illumination (100 mW/cm 2 ). This study could provide insight for the low-cost, facile, and efficient interface modification for the pero-SCs.

Buried Interface Modification in Perovskite Solar Cells: A Materials Perspective

“…Beyond that, it can passivate the defects at the interface between perovskite and ETL and also result in better energy-level alignment between perovskite and ETL, which could facilitate the carrier transport and reduce the energy loss. [57] There are very few studies on polymers for modifying the buried bottom interface, but theoretical research has shown that these polymers have great potential to better regulate the bottom interface. Due to the inherent insulating properties of polymer materials, these make polymer materials a doubleedged sword.…”

“…Beyond that, it can passivate the defects at the interface between perovskite and ETL and also result in better energy‐level alignment between perovskite and ETL, which could facilitate the carrier transport and reduce the energy loss. [ 57 ]…”

“…[ 54 ] Nowadays, some materials have been developed to tailor the buried interface for both regular and inverted PSCs with pre‐processing or post‐processing the bottom CTLs. [ 19,55–57 ] For example, the recent development of buried interface research has made a great breakthrough in the PSCs with the highest certification record. [ 23 ]…”

Multifunctional Molecule‐Modified SnO2–Perovskite Interface for Efficient Planar Perovskite Solar Cells

“…The reported doping elements include Mg, [6] Nb, [7] Sb, [8] Ta, [9] Y, [10] Li, [11] Ga, [12] Mo, [13] rare-earth ion, [14] and alkali chloride. [15] The reported additives include triphenylphosphine oxide molecule, [16] carbon quantum dots, [17][18] carbon nanotubes, [19] graphene quantum dots, [20] LiF, [21] RbF, [22] EDTA-2M, [23] Nb 2 C MXenes, [24] gold nanostars, [25] black phosphorus, [26] polymer, [27] and so on. In addition, there are some report about multiple ETL with other metal oxides [28] and surface modification including π-conjugated small molecules, [29] thiophene, [30] p-amino benzenesulfonic acid, [31] 4-imidazoleacetic acid hydrochloride, [32] sulfonium salt, [33] TiCl 4 , [34] fullerene, [35][36] and so on.…”

Compact SnO2/Mesoporous TiO2 Bilayer Electron Transport Layer for Perovskite Solar Cells Fabricated at Low Process Temperature

“…To achieve highly efficient PSCs using a SnO 2 ETL, SnO 2 ETL combination and surface modification techniques that can improve electron injection and suppress electron recombination have been developed [13]. Various inorganic metal oxides, such as ZnO [14], MgO [15], and TiO 2 [16,17], as well as organics, including carbon-based materials [18], self-assembled monolayers (SAM) [19], and polymers [20], have been adopted in SnO 2 ETL-based PSCs to combine with or modify SnO 2 . Among them, the conventional m-TiO 2 layer is the preferable candidate to be combined with the compact SnO 2 (c-SnO 2 ) layer because the mesoporous scaffold can facilitate sufficient pore filling of the light-absorbing layer and improve electron extraction and transport over a single c-SnO 2 layer [17,21].…”