We report on magnetotransport studies of regio regular poly (3-hexyl thiophene) (RRP3HT) based diodes and P3HT: 1-(3-methoxycarbonyl)propyl-1-phenyl-[6,6]- methanofullerene (PCBM) bulk heterojunction solar cells. While the P3HT diodes with non-magnetic electrodes ITO and Al show up to 16% positive magnetoresistance (MR) under 300 mT magnetic field at room temperature, solar cells with much reduced electronhole pair (e-h) formation probability show almost negligible MR clearly suggesting that MR in organic semiconductors is strongly dependent on the probability of forming Coulombically bound e-h pairs. Voltage and temperature dependence of MR sign and magnitude is discussed for the diode devices which provides important insight of the scientifically puzzling yet technologically very promising magnetotransport properties of organic semiconductor based devices.
Majumdar, S., Majumdar, H. S., Aarnio, H., Laiho, R., & Osterbacka, R. (2009). Magnetoresistance in Poly (3-hexyl thiophene) Based Diodes and Bulk Heterojunction Solar Cells. In Interface Controlled Organic Thin Films (pp. 127-131). Springer. https://doi.org/10.1007/978-3-540-95930-4_21