One-step Co-fabrication of tripod self-organized hole transport and perovskite layers for perovskite solar cells

The use of self-assembled materials (SAM) in the hole transport layer (HTL) of inverted (p-i-n) perovskite solar cells (PSCs) has been a subject of growing interest. This is mainly due to their ability to achieve high HTL coverage with minimal film thickness, even on rough substrates, and to reduce the perovskite interface energy barrier. However, a common issue is a reduction in perovskite layer coverage on SAM. A novel one-step simultaneous co-formation of the p-i layer has been proposed to address this, involving the addition of SAM to the perovskite precursor solution.

This investigation explores the morphology and the physical properties of perovskite thin films produced using the one-step formation of the p-i layer without antisolvent, with the recently developed multipodal molecule[[5H-diindolo[3,2-a:3′,2′-c]carbazole-5,10,15-triyl]tris(propane-3,1-diyl)] trisphosphonic acid(3PATAT-C3), which exhibits a face-on molecular orientation. Results demonstrated that introducing 3PATAT-C3 into the perovskite precursor solution yielded improvements in passivation and promoted charge extraction.

The PSCs utilizing the one-step p-i co-deposition exhibited a remarkable power conversion efficiency (PCE) of 21.4 % and a fill factor of 78.7 %. These results outperformed the reference devices fabricated by depositing perovskite on SAM. Furthermore, statistical analyses indicate that hysteresis in current density–voltage curves has been reduced. These outcomes suggest that the one-step p-i co-deposition technique matches and potentially surpasses the performance of traditionally manufactured cells. Moreover, it achieves this with fewer fabrication steps, thereby representing a substantial advancement toward its commercial viability, instilling hope for the future of solar cell technology.