Resolving the Hydrophobicity of Me-4PACz Hole Transport Layer for High-Efficiency Inverted Perovskite Solar Cells

• DOI: 10.48550/arxiv.2304.13788
• Publication Date: 2023-01-01
• Authors: Kashimul Hossain; Ashish A. Kulkarni; Urvashi Bothra; Benjamin Klingebiel; Thomas Kirchartz; Michael Saliba; Dinesh Kabra
• Keywords: Condensed Matter - Materials Science; Materials Science (cond-mat.mtrl-sci); FOS: Physical sciences; 7. Clean energy

[4-(3,6-dimethyl-9H-carbazole-9-yl)butyl]phosphonic acid (Me-4PACz) self-assembled monolayer (SAM) has been employed in perovskite single junction and tandem devices demonstrating high efficiencies. However, a uniform layer does not form due to the hydrophobicity of Me-4PACz. Here, we tackle this challenge by adding conjugated polyelectrolyte poly(9,9-bis(3'-(N,N-dimethyl)-N-ethylammonium-propyl-2,7-fluorene)-alt-2,7-(9,9dioctylfluorene)dibromide (PFN-Br) Me-4PACz specific ratio, defines as Pz:PFN. With mixing engineering strategy Pz:PFN, PFN-Br interacts with A-site cation is confirmed via solution-state nuclear magnetic resonance studies. The narrow full width at half maximum (FWHM) diffraction peaks film revealed improved crystallization on optimal ratio Interestingly, additionally tunes work function Kelvin probe force microscopy built-in-voltage estimation solar cells. Devices employing optimized Pz:PFN deliver open-circuit voltage (Voc)of 1.16 V efficiency >20% for perovskites bandgap 1.6 eV reproducibility concomitant stability. Considering significant research SAM, our highlights importance obtaining yield performance.