  Charge transfer in polymer devices represents a crucial, though highly
inaccessible stage of photocurrent generation. In this article we propose
studying the properties and behaviour of organic solar cells through the
modification of photocurrent generation when an external magnetic field is
applied. By allowing the parameters of our theoretical model not to be
constrained to any specific material, we are able to show that not only a
modest external magnetic field leads to a significant increase in photocurrent
intensity, but also how such magnetic field can be used to study in detail the
energy levels and transition rates within the polymer compound. Systematic
exploration of key properties in organic composites thus can lead to highly
optimised devices in which a magnetic field produces an enhancement in the
efficiency of polymer solar cells.
