Photoresponse and saturation behavior of organic thin film transistors
Photoresponse and saturation behavior of organic thin film transistors
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DOI：
10.1063/1.3068359
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发表时间：
2009-01
影响因子：
3.2
通讯作者：
K. Wasapinyokul;W. Milne;D. Chu
中科院分区：
文献类型：
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作者：
K. Wasapinyokul;W. Milne;D. Chu
基于聚(3，3-二十二烷基季噻吩基)的有机薄膜晶体管在固定波长和从暗到1100μW cm−2的不同强度的照明下进行了表征。典型的照明过程是通过增加沟道中以极化子形式存在的电荷载流子数量来增加漏电流，这是激子或电子-空穴对产生和解离的结果。然而，电流增加的速度随着光强的增加而减小，最终漏电流水平在下降之前达到最大值。我们认为，这种过饱和行为背后的物理原因与电子-空穴复合事件的数量增加有关，这些事件与通道中极化子密度的增加有关。当极化子密度在强光强下超过阈值时，极化子数不能进一步增加，因为它们已经紧密堆积在一起，复合超过了生成，r。
Organic thin film transistors based on poly(3,3‴-didodecylquarter-thiophene) were characterized under illumination with a fixed wavelength but various intensities from dark to 1100 μW cm−2. Typically the illumination process should increase the drain current through the increase in the number of charge carriers in the channel in the form of polarons, as a result of generation and dissociation of excitons or electron-hole pairs. However, the rate of the current increase was found to decrease as the light intensity was increased, and eventually the level of drain current reached a maximum before declining. We suggest that the physics behind this oversaturation behavior is related to the increasing number of electron-hole recombination events associated with the increase in polaron density in the channel. When the polaron density goes above a threshold value at high light intensity, the number of polarons cannot increase further as they are already closely packed and the recombination overtakes generation, r...