采用真空升华的方法, 对国产纯度为98%的苝四甲酸二酐（简称PTCDA）粉末, 在其升华点450 ℃进行了提纯。 应用朗伯比尔定律及紫外-可见光分光光度计测试分析, 其纯度可达99.8%; 利用元素分析仪, 对提纯前、 后分子中的C元素和H元素含量进行了对比测定, 结果表明提纯后的PTCDA分子中C和H含量十分接近理论值; 采用核磁共振（NMR）谱, 研究了分子中H元素的归属得出, 处于两种不同化学环境中的H原子数目相等并且它位于芳环上, 其分子中存在酸酐; 对PTCDA分子的化学键的形成讨论后得出, 高纯度PTCDA分子中的C, H, O原子主要以共价键结合; 使用X射线衍射（XRD）仪, 测试分析了这种有机材料的结晶状态及其晶体结构指出, 提纯后的PTCDA多晶粉末存在α-PTCDA及β-PTCDA两种物相, 主要成份为α-PTCDA, 而β-PTCDA约占总成份的五分之一。 其晶胞属于平面单斜晶系底心点阵结构。 同时详细研究了在其升华点沉积在P型单晶Si（100）表面, 由此形成薄膜的晶体状态及其晶粒度的尺寸和能带结构。 高纯度α-PTCDA分子在P—Si单晶表面形成有机层单晶薄膜时, 在其薄膜的分子层平面的上、 下及其两侧, 将由π电子云所覆盖。 由于C, H和O原子最外层价电子轨道的交叠形成离域大π键, 从而产生价电子的共有化运动, 使其能级分裂为能带。 它的价带与第一紧束缚带的能量差为2.2 eV, 使这种有机材料具有半导体导电的性质, 本征载流子浓度为1014 cm-3, 属于弱p型有机半导体材料; 它与P—Si的交界面可形成同型异质结, 对可见光至近红外波段的光有很好地响应。

vacuum sublimation method was used to purify the homegrown 3,4,9,10 perylenetetracarboxylic dianhydride（PTCDA）powder with a purity of 98% in its sublimation point of 450 ℃. With Bill’s law and ultraviolet-visible spectrophotometer testing analysis, its purity reached to 99.8%. Meanwhile, the contents of C and H elements in the pre-and post-purified molecules were also measured by using elemental analyzer. The measured results indicate that the contents of C and H elements in the post-purified the molecules are very close to the theoretical value. H element in the molecular structure was investigated with nuclear magnetic resonance (NMR) spectroscopy and the results demonstrated that there are an equal number of H atoms in two different chemical environments and it can only be located on the aromatic ring. By discussing the chemical bond formation of PTCDA molecules, the C, H and O atoms in high purity PTCDA molecules are mainly covalent bonds. The crystalline state and crystal structure of this organic material were tested and analyzed by X-ray diffractometer. The results suggest that the post-purified PTCDA power existed α-PTCDA and β-PTCDA two phases, in which α-PTCDA phase is major component while β-PTCDA phase accounts for about one five of the total ingredients. Besides, the crystal cell belonged to bottom-centered monoclinal structure. Meanwhile, the crystal state, grain size and band structure of PTCDA single crystal thin films formed on the surface of p-type silicon in its sublimation point are investigated in detail. During the high-purity α-PTCDA forming organic single thin film on the surface of p-type single silicon, the π-electron cloud covered on the top, bottom and two sides of its thin film’s molecular layer plane. Due to the formation of delocalized bond that attributed to the overlap of the outermost valence electron orbital of C, H, O atom, the valence electrons generate co-movement and the energy level splitting for the band. The energy difference between valence band and the first tight binding is 2.2 eV which lead to this organic material possessing the properties of semiconductor conduction. In addition, this organic material with the intrinsic carrier concentration for 1014 cm-3 belong to weak p-type organic semiconductor material. This organic material combines with the surface of p-type silicon to form hetehomo-type heterojunction which is provided with excellent response for visible light to near infrared wavelengths of light.