Chemical Engineering Department and Frontier Research Center on Fundamental and Applied Sciences of Matters, National Tsing-Hua University, Hsinchu, Taiwan, Republic of China.
ACS Appl Mater Interfaces. 2013 May 22;5(10):4086-92. doi: 10.1021/am303186f. Epub 2013 May 2.
Thermally stimulated current (TSC) technique is used to characterize traps in the regioregular poly(3-hexylthiophene) (rr-P3HT) and its blend with [6,6]-phenyl-C61-butyric acid methyl ester (PCBM). A hole trap in bulk rr-P3HT and an interfacial hole trap located at indium tin oxide (ITO)/rr-P3HT interface are revealed from the TSC measurement. Besides, molecular oxygen (O2) can form a deep electron trap with an onset of detrapping temperature at 225 K in rr-P3HT, in which O2 is located at the main chain region and the detrapping process is induced by chain motions under elevated temperature. In the blend of rr-P3HT:PCBM (1:1 w/w), additional hole trap states are generated in this blend system as compared to those of pure rr-P3HT and PCBM; however, these hole trap states can be reduced by thermal or solvent annealing approaches. Similar to rr-P3HT, a deep electron trap with an onset of detrapping temperature at 250 K can be formed in the blend after O2 exposure. In the case of low PCBM content in the blend (rr-P3HT:PCBM weight ratio of 4:1), an additional electron trap is generated.
热刺激电流（TSC）技术用于表征区域规整聚（3-己基噻吩）（rr-P3HT）及其与[6,6]-苯基-C61-丁酸甲酯（PCBM）的混合物中的陷阱。从 TSC 测量中揭示了体相 rr-P3HT 中的空穴陷阱和位于铟锡氧化物（ITO）/rr-P3HT 界面处的界面空穴陷阱。此外，分子氧（O2）可以在 rr-P3HT 中形成一个深电子陷阱，其脱陷阱温度起始于 225 K，其中 O2 位于主链区域，脱陷阱过程由高温下的链运动引发。在 rr-P3HT:PCBM（1:1 w/w）的混合物中，与纯 rr-P3HT 和 PCBM 相比，在该混合物体系中产生了额外的空穴陷阱态；然而，这些空穴陷阱态可以通过热或溶剂退火方法来减少。类似于 rr-P3HT，在 O2 暴露后，混合物中可以形成起始脱陷阱温度为 250 K 的深电子陷阱。在混合物中 PCBM 含量较低的情况下（rr-P3HT:PCBM 重量比为 4:1），会产生额外的电子陷阱。
