The photocurrent responses of organic MIM junctions were investigated for light chopped at various frequencies in the temperature range between 300 K and 1.5 K. The responses to different chopping frequencies exhibited different temperature dependences. A light-chopped photocurrent markedly decreased under magnetic fields at low temperatures. An experiment of photoinduced charge extraction by linearly increasing voltage (photo-CELIV) was performed at 1.4 K to reveal the origin of this phenomenon. A drastic increase in the lifetime was observed for trapped carriers under applied magnetic field. (C) 2009 Elsevier B.V. All rights reserved.