[17p-B201-1~7] pMAIRS: A cutting-edge technique revealing the molecular orientation even in an amorphous thin film having a surface roughness

[17p-B201-6] Molecular Orientation Control of Organic Semiconductors for Efficient Perovskite Solar Cells

〇Atsushi Wakamiya¹, Tomoya Nakamura¹, Nobutaka Shioya¹, Takafumi Shimoaka¹, Takeshi Hasegawa¹, Yasujiro Murata¹ (1.Kyoto Univ.)

Keywords:Organic semiconductor, Perovskite solar cells, pMAIRS

We focused on the naphthalene diimide (NDI) skeleton as transparent n-type semiconducting alternative materials for Perovskite solar cells. By introducing hydrogen atoms at the imide moiety, we envisioned the achievement of face-on orientation on the substrates, which is preferable for vertical charge transport, by the formation of intermolecular N–H···O hydrogen bondings. To realize both the solution-processability and the durability to the deposition of the upper layers, we designed NDI-Boc having tert-butoxycarbonyl (Boc) solubilizing groups at the imide moiety, which can be cleaved by simple thermal annealing. Infrared p-polarized multiple-angle incidence resolution spectroscopy (pMAIRS) not only confirmed the cleavage of the Boc group, but also revealed that the molecular orientation of NDI changed from edge-on to face-on during the cleavage process.