Origin of Radiation Induced Damage in Organic P3HT:PCBM Based Photocells

Abstract

Organic semiconductor photocells based upon P3HT:PCBM (1:1 by weight) have been subjected to X irradiation. The carrier lifetime has been determined using a pulsed optical method with continuous light to generate an open circuit voltage bias. No effect is observed on the carrier lifetime up to 300 krad (SiO 2 ). However, changes in the open circuit voltage are observed and we argue that these result from compensation of the internal field which results from the built-in potential. The origin of the field modifications must lay in the presence of radiation induced trapped charge near the organic semiconductor/anode and/or cathode interfaces.

Characterization of an organic semiconductor diode for dosimetry in radiotherapy

“…However, unlike their crystalline solid-state counterparts, there is no one distinct junction between the two materials as they are structured as a blended heterojunction. The most common donor material for organic solar cells is the conjugated polymer poly(3-hexylthiophene) (P3HT) blended with fullerene derivative phenyl-C61-butyric acid methyl ester (PCBM) as the acceptor 41,42 . The use of P3HT:PCBM to measure 70kV x-rays has been reported within the context of their exploitation in the field of medical imaging, showing that with the aid of a NaI(Tl) or a CsI(Tl) scintillator the device response is linearly dependent on the x-ray dose rate 43 .…”

“…The most common donor material for organic solar cells is the conjugated polymer poly(3hexylthiophene) (P3HT) blended with fullerene derivative phenyl-C61-butyric acid methyl ester (PCBM) as the acceptor. 41,42 The use of P3HT:PCBM to measure 70 kV x rays has been reported within the context of their exploitation in the field of medical imaging, showing that with the aid of a NaI(Tl) or a CsI(Tl) scintillator the device response is linearly dependent on the x-ray dose rate. 43 This material has also been shown to be sensitive to 6 MV x rays via indirect detection (Gd 2 O 2 S:Tb phosphor material) with stable performance (2% loss in photocurrent) up to 360 Gy, 44 suggesting its longevity for applications in ionizing radiation environments.…”

Interface design to improve stability of polymer solar cells for potential space applications

“…From the point view of space applications, a good benchmark for OPV is a PCE of 12-15% to compete with other technologies, which is also aligned with the prediction of OPV efficiency limit. 3 We have investigated earlier 5,6 the reason for degradation of polymer solar cells when subjected to X-ray radiation. It was found that no significant changes took place in the polymer structure; the morphology and crystallinity of the photoactive layer are retained after radiation.…”

“…We systematically study the effect of X-ray irradiation on five different polymer/cathode interfaces. We fix the polymer active layer to the work horse poly(3hexylthiophene) (P3HT): [6,6]-phenyl-C61-butyric acid methyl ester (PCBM) system and vary the cathode to Al, Ca/Al, LiF/Al, TiO 2 :Cs/ Al and ZnO/Al interface to reveal the underlying phenomenon.…”