Studies of reflectivity and transport properties of crystals of porphyrin doped with2CdI4-2 、4I-1 、6I-1

Abstract

本論文中我們研究掺雜2CdI4-2 、4I-1 、6I-1 之porphyrin晶體：H2TEPyP-2CdI4-2、H2TEPyP-4I-1 、H2TEPyP-6I-1 ，從波長400nm~1050nm的反射偏極光譜，和傳輸特性。由光譜可以觀察到三種樣品具有porphyrin的指紋(fingerprint)：B band (400nm~500nm)與Q band (500nm~700nm)。 我們改變電場方向，觀察反射光譜的變化，發現當樣品平躺時，只有H2TEPyP-2CdI4-2在B band範圍具有方向性，但在700nm~1050nm範圍，三種樣品卻都具方向性。然而當樣品直立時，則全部都無方向性。 最後我們對樣品作四點量測，每樣品各得到一個臨界溫度，當溫度高於臨界溫度時，導電率會隨溫度上升而急速上升，呈現出兩種不同的物理特性，85K與325K的導電率相差10~1000倍。

This research studies the crystals of porphyrin doped with 2CdI4-2, 4I-, and 6I- by measuring the polarized reflection spectra (400nm~1050nm) and temperature dependent transport properties. The spectra of the three samples all reveal the fingerprints of porphyrin: B band (400nm~500nm) and Q band (500nm~700nm). We observe changes in the reflection spectra, when the direction of electric field of the incident light is changed. When the samples lie down, only H2TEPyP-2CdI4-2 shows isotropic B band; however, in the range from 700nm to 1050nm, all three samples have isotropy. On the contrary, when standing, all samples show anisotropy. Resistivity measurements were conducted by the four-wire method. At temperatures higher than the critical temperature, the conductivity rises drastically with rising temperature. The conductivity increases by 10~1000 times as the temperature rises from 85K to 325K.