Modulating Binding Strength and Acidity of Benzene-Derivative Ligands Enables Efficient and Hysteresis-Free Perovskite/Silicon Tandem Solar Cells.

Passivating defects at the wide-bandgap perovskite/C60 interface without impeding interfacial charge transport can effectively enhance the efficiency of perovskite/silicon tandem solar cells (TSCs). Herein, we study the impact of benzene-derivative ligands with elaborately modulated binding strength and acidity on wide-bandgap perovskites for high-performance perovskite/silicon TSCs. Specifically, the acidity/alkalinity and binding strength are preliminary tuned using different functional groups of -PO₃H₂, -COOH, and -NH₂, and further finely adjusted by altering the chain lengths between the benzene ring and the functional groups.

Synergistic Ionic Liquid in Hole Transport Layers for Highly Stable and Efficient Perovskite Solar Cells.

Perovskite solar cells (PSCs) with n-i-p structures often utilize an organic 2,2',7,7'-tetrakis (N, N-di-p-methoxyphenyl-amine) 9,9'-spirobifluorene (spiro-OMeTAD) along with additives of lithium bis(trifluoromethanesulfonyl)imide salt (LiTFSI) and tert-butylpyridine as the hole transporting layer (HTL). However, the HTL lacks stability in ambient air, and numerous defects are often present on the perovskite surface, which is not conducive to a stable and efficient PSC. Therefore, constructive strategies that simultaneously stabilize spiro-OMeTAD and passivate the perovskite surface are required.

Enhanced photovoltage and stability of perovskite photovoltaics enabled by a cyclohexylmethylammonium iodide-based 2D perovskite passivation layer.

Regardless of the impressive progress that perovskite solar cells (PSCs) have achieved, especially considering their power conversion efficiency (PCE) over 25%, traditional PSCs still contend with an inherent instability with exposure to humidity, which remains as a critical issue for the realization of commercial production. Herein, we proposed an effective pathway to relieve the instability of PSCs without sacrificing efficiency by introducing a 2D phase at the surface of the 3D perovskite film, based on a novel organic cyclohexylmethylammonium iodide (CMAI). The self-assembled thin 2D capping layer atop the 3D perovskite layer can not only reduce the ionic defects, but also serve as a protective barrier against moisture.