講演情報
[10p-A22-3]Contact-free mapping of mapping of band bending kinetics inPEACL-modified perovskites
〇Manjakavahoaka Razanoelina1, Tomoya Hiei1, Tatsu Murao1, Takahiro Teramoto2, Hidetoshi Nakanishi1, Toshiya Doi1, Iwao Kawayama1 (1.Kyoto Univ, 2.Univ. of Kitakyushu)
キーワード：
Terahertz、perovskite
Interfacial electric fields govern charge separation and extraction in perovskite solar cells, but their ultrafast response to chemical passivation remains difficult to probe directly. We used reflection-mode THz emission spectroscopy to study PEACl-passivated and non-passivated Cs0.05(FA0.76MA0.24)0.95Pb(I0.76Br0.24)3 perovskite samples. The absorber band gap was 1.68 eV, and excitation was performed from the perovskite surface using 100 fs pulses at 360–420 nm and 700–800 nm. At 700 nm, near the absorption edge, THz emission is mainly sensitive to surface-field-driven drift currents. Polarity calibration with InAs showed upward band bending in non-passivated samples, while PEACl passivation reversed the THz polarity, consistent with downward band bending. This reversal suggests that PEACl changes the surface potential through defect passivation, interfacial dipoles, and formation of a thin low-dimensional perovskite layer.