Figure 1

(a) Integrated cwEDMR spectrum (gray squares) obtained at room temperature without illumination. The solid line represents a fit assuming two resonance lines with equal doubly integrated intensities and $g$ values but different line shapes. The solid and dashed lines show the individual fit components. (b) $B_1$ dependence of the pEDMR spectrum (integrated current change following a 160 ns mw pulse, maximum relative current change: $\Delta I/I=3\times {10}^{-5}$).Reuse & Permissions

Figure 2

Electrically detected spin-Rabi nutations obtained at room temperature. (a) Integrated charge $Q$ as a function of the mw pulse length $\tau$ for several values of $B_1$ and simulation results for bipolaron formation (dotted curves, vertically offset downwards). (b) Fast Fourier Transform (FFT) of the data shown in (a). With increasing $B_1$ the intensity (represented by the color code) of the $\Omega$ component decreases whereas the intensity of the $2\Omega$ component increases.Reuse & Permissions

Figure 3

Bipolaron formation under resonant microwave excitation. In the scheme polaron charge and spin are indicated by $+$ and arrow, respectively. Gray shaded ellipses indicate trap sites accommodating $P^{+}$ or bipolarons. From left to right polarons form weakly coupled spin pairs in a mixed singlet ($S$) triplet ($T$) state upon encounter of mobile and trapped polarons. Resonant mw excitation alters the $S$ and $T$ content, with an oscillation frequency $\Omega$ (no spin locking) or $2\Omega$ (spin locking). ISC transfers population from $T^0$ to $S$. Depending on the $S$ and $T$ content of the pair, either triplet $P^{+}{P}^{+}$ pairs (transport blocked) or bipolarons (transport allowed) are formed.Reuse & Permissions