Transformation of polycrystalline layers of BEDT–TTF triiodide salt by reaction with Br2

A new way of controlling of properties of surface conducting polymer/organic conductor composites is presented. It is demonstrated that a reaction of Br2 with α-ET2I3 microcrystals followed by annealing transforms the PC/α-ET2I3 system into PC/α-ET2IBr2. This transformation leads to significant changes of the electrical and optical properties. Interestingly, even if the reaction leads to deterioration of the microcrystals, the continuity of the conducting network is preserved.