Electrically Detected Magnetic Resonance Observations of Spin‐Dependent Space‐Charge‐Limited Conduction in Regioregular Poly(3‐Hexylthiophene)

Pauli spin blockade associated with bipolaron formation from positively charged mobile and trapped polarons in a regioregular poly(3‐hexylthiophene‐2,5‐diyl) (RR‐P3HT) Schottky barrier diode is detected using electrically detected magnetic resonance (EDMR) spectroscopy. This is the first experimental observation of bipolaron formation from positively charged mobile and trapped polarons in the space‐charge‐limited conduction regime in a polymer semiconductor. It is inferred that carrier traps exist in the disordered regions at the crystalline grain boundaries in RR‐P3HT. Furthermore, EDMR measurements under various constant‐current conditions suggest that shallow and deep traps have distinguishable g‐values. Spin‐dependent bipolaron formation from positively charged mobile and trapped polarons in a regioregular poly(3‐hexylthiophene‐2,5‐diyl) Schottky barrier diode is detected using electrically detected magnetic resonance and carrier traps are found to exist in the crystalline grain boundaries in the polymer.