有機半導體駢苯衍生物(PTCDI)之光電性質研究

Electro-optical properties of Organic Semiconductor-Perylene Diimide Derivative (PTCDI)

周俊賢

指導教授 ： 陸健榮

國立臺灣師範大學/理學院/物理學系/碩士(2007年)

摘要

本論文以電場調制吸收光譜(ER)，電流-電壓曲線(I-V)，以及光激螢光實驗(PL)來探討N型有機半導體-PTCDI鏈結不同烷基鍵(PTCDI-
CxH2x+1 , x=2,3,4,5,6,7,8 )的光電特性。
量測I-V曲線以得知樣品內部電場分佈。無光照情況下，樣品內部電場為類蕭特基二極體分佈(Schottky-diode-like distribution)；而在照光情況下，樣品產生光電流，內部電場成空間電荷侷限分佈(Space
-charge-limited distribution)，在施加調制電壓範圍內I-V為線性。
在電場調制吸收光譜實驗中，對樣品施加電場產生史塔克效應(Stark effect)後，得到的譜形結構主要以高斯一次及二次微分譜形組成。比較吸收光譜及電場調制光譜所得各躍遷能量，與文獻對照後得知各樣品的HOMO-LUMO躍遷應為2.2 eV左右。另外，調制光譜強度與施加的交流調制電壓成正比關係。
由光激螢光實驗得到，樣品螢光躍遷能量皆低於HOMO-LUMO躍遷能量，且螢光強度與溫度的變化關係可以用熱活化非輻射複合模型(thermally activated non-radiative recombination)來解釋。

關鍵字

有機半導體 ； 駢苯衍生物 ； 電場調制光譜 ； 光激螢光 ； 熱活化非輻射複合

並列摘要

In this thesis, we used Electroabsorption Spectroscopy(ER), I-V Curve and Photoluminscence(PL) to investigate the electro-optical properties of Perylene Diimide Derivative-PTCDI with various Alkyl (PTCDI-CxH2x+1, x = 2,3,4,5,6,7,8).

We can understand the internal electric field distribution by I-V Curve measurement. Without illumination, the electric field is Schottky diode like distribution in the organic layer; nevertheless, with the lighting, it is Space charge limited electric field distribution. Between the range of the applied voltage(+1.4 ~ -1.4 Vac), the I-V Curve is linear behavior.

In ER measurements, a AC voltage as external electric field is applied to the sample, and it will cause the Stark effect. The structures of the spectrum are formed with the first and second order differential of Gauss functions. Compare with absorption measurement and the reference, the structure in 2.2 eV should be the HOMO-LUMO transition. Further, the strength of ER is direct proportion to the applied AC voltage.

In PL measurement, the transitions all below the HOMO-LUMO transition. The relation between the strength of PL and temperature can explain by the thermal activated non-radiative recombination model.

並列關鍵字

PTCDI ； HOMO-LUMO

參考文獻

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