Roles of Long‐Chain Alkylamine Ligands in Triple‐Halide Perovskites for Efficient NiO_x‐Based Inverted Perovskite Solar Cells

Abstract

The passivation of perovskite bulk and heterointerface defects is one of the most significant ways to enhance the efficiency and operational stability of perovskite solar cells (PSCs). So far, ammonium‐based alkylamine halides have been considered as effective passivation materials to reduce defects of the perovskite absorber layer. Herein, roles of long‐chain alkylamine ligands (LALs) in triple‐halide perovskites are systematically studied for achieving efficient NiOx‐based inverted PSCs. Two kinds of LALs oleylammonium (OAm) and phenethylammonium (PEA), as perovskite bulk and interface passivation agents, respectively, are introduced. It is found that both OAm and PEA ligands cannot only assist their crystal growth with vertical orientation, but also suppress triple‐halide perovskite bulk and interface defects. As precursor additives, OAm ligands can be used as organic spacers to assist the generation of the 2D@3D perovskite bulk crystals. 2D@3D/2D perovskite heterostructures are further formed when the 2D@3D perovskite bulk film is post‐treated by PEA ligands. As a result, such strategies enable hysteresis‐free and highly efficient NiOx‐based triple‐halide inverted PSCs.

Review of Defect Passivation for NiOx-Based Inverted Perovskite Solar Cells

“…Ju et al studied the passivation effect of oleylammonium (OAm) for perovskite films. 140 It was found that OAm ligands not only contributed to the vertical orientation of crystal growth but also suppressed bulk and interface defects of perovskite films. In addition, OAm ligands could act as an organic spacer to assist the formation of 2D@ 3D perovskite crystals.…”

“…This value was 30 times longer than previously reported inverted PSCs (Figure a–f). Ju et al studied the passivation effect of oleylammonium (OAm) for perovskite films . It was found that OAm ligands not only contributed to the vertical orientation of crystal growth but also suppressed bulk and interface defects of perovskite films.…”

Passivating Defects at the Bottom Interface of Perovskite by Ethylammonium to Improve the Performance of Perovskite Solar Cells

“…As for the bottom interface, some modifications were also proposed. [13][14][15][16][17][18][19] For example, the interface between SnO 2 and perovskite can be modified with ion liquids or polymer framework. [16,17] The interface between NiO x and perovskite could be passivated by guanidinium (GA) cations and led to a PCE of 22.9%.…”

Perovskite/Hole Transport Layer Interfacial Engineering with Substoichiometric Tungsten Oxide Rich in Oxygen Vacancies to Boost the Photovoltaic Performance of Perovskite Solar Cells

“…The stability is an important index to evaluate the commercial possibility of one device. [67][68][69][70][71][72] The stabilized current density and PCE of the control and WO 3ÀX (600 °C)-based devices were measured under the maximum power point (V mpp ) of 0.91 and 0.95 V in 250 s continuous illumination. As shown in Figure 7a, the PCEs of the control and WO 3ÀX (600 °C)-based devices stabilize at 18.45 and 20.99%, and the corresponding current density stabilizes at 20.28 and 22.09 mA cm À2 , respectively.…”