酞菁氧钛/N,N-二甲苯基苝酰亚胺复合薄膜的光伏极性反转

用表面光电压谱和电场诱导表面光电压谱相结合的方法, 研究了酞菁氧钛/N,N-二甲苯基苝酰亚胺复合薄膜的表面光伏行为, 发现加入N,N-二甲苯基苝酰亚胺使复合薄膜在可见光区和近红外光区均产生负的光伏响应, 可归结为光伏极性反转现象. 该响应随着外加偏压方向的改变而改变正负值, 表现出表面态跃迁的特征.  根据N,N-二甲苯基苝酰亚胺n型半导体的性质,  从价带到表面态和从表面态到导带的跃迁能量的差别以及依赖于偏压方向的电场诱导表面光伏响应,  确认表面态来自N,N-二甲苯基苝酰亚胺组分.

Photovoltaic Polarity Inversion in Thin Films of Titanoxophthalocyanine/N,N-Bistolylperylene Tetracarboxylic Dimimide Composite Films

Surface photovoltaic behavior of titanoxophthalocyanine(TiOPc)/N,N-bistolylperylene tetracarboxylic diimide(ToPTCDI) composite films was investigated with surface photovoltaic spectroscopy(SPS) and field induced surface photovoltaic spectroscopy(FISPS).It was found that the introduction of ToPTCDI into TiOPC could result in negative SPS response both in visible and in near-infrared spectral regions,which was assigned to the phenomenon of photovoltaic polarity inversion.The polarity of the SPS signals could be tuned by external bias,showing the characteristic of surface electronic states.Based on the n-type nature of ToPTCDI,the energy space between the optical transitions from valence band to surface state and from surface state to conduction band,as well the bias-direction dependent FISPS signals,the origin of the surface electronic state was ascribed to ToPTCDI component.