Effects of PCBM loading on high sensitive P3HT based vertical bulk resistive X-ray detector

Recently, semiconductive polymeric materials have attracted attention as an active layer for detecting ionizing radiation because of their excellent properties such as flexibility, easy production, solution processability and low-cost production. This paper presents X-ray detection properties of Poly(3-hexylthiophene) (P3HT):Phenyl C61 butyric acid methyl ester (PCBM) blend structure with different PCBM loading ratios. P3HT:PCBM mixing ratio was changed from 1:0 to 1:2. Top contact of the pure and blend structured device were produced by using a solution based graphite ink. Devices were constructed with vertical bulk resistive architecture within an ohmic electrode structure as ITO/PEDOT:PSS/P3HT:PCBM/Graphite configuration. Graphite electrode was coated on the active layer with the spray coating method. All devices exhibited ohmic current-voltage (I-V) characteristics. The blend structured devices exhibited stable saw-tooth type behaviour in photocurrent responses against the on and off states of X-rays. Saw-tooth type responses could be evaluated as major evidence for a potential usage of organic electronic device technology direct radiation detectors. Although the best sensitivity value to X-ray was obtained with the blend structure with equal ratio, it was observed that the rise and decay times were shortened with the increase in the amount of PCBM in the blend structure from.

Automated summary

This paper investigates the X-ray detection properties of different Poly(3-hexylthiophene) (P3HT):Phenyl C61 butyric acid methyl ester (PCBM) blend structures by changing the PCBM loading ratios. The results show that the blend structured devices exhibit stable saw-tooth type behavior in photocurrent responses, indicating their potential application as organic electronic radiation detectors.