Table 1.
Comparison of electronically and optically measured DOS
| Polymer | EB (meV) | Eu (meV) | EDOS (meV) | µSCLC (cm2/Vs) | µFET (cm2/Vs)11,20 |
|---|---|---|---|---|---|
| MEH-PPV | >60 | 39 ± 2 | 60 ± 10 | 0.0001 | 0.0001 |
| IDT-BT | 24 | 24 ± 2 | 23 ± 3 | 0.02 | 2 |
| DPP-DTT | 30 | 31 ± 2 | 39 ± 5 | 0.03 | 1 |
| DPP-BTz | 28 | 32 ± 2 | 36 ± 5 | 0.2 | 2 |
Comparison of the width of the tail of trap states extracted from analysis of the r value (EB), from an exponential fit of the dn/dE curves from SCLC spectroscopy (EDOS) and the Urbach energies extracted from optical absorption spectroscopy (Eu) along with a comparison of FET and SCLC mobilities measured for the polymers MEH-PPV, IDT-BT, DPP-BTz, and DPP-DTT. The given errors were estimated from the uncertainty in the extraction procedure.
FET field-effect transistor, MEH-PPV poly[2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylenevinylene], IDT-BT indacenodithiophene-co-benzothiadiazole, DPP-BTz poly[[2,5-bis(2-octadecyl)-2,3,5,6-tetrahydro-3,6-diketopyrrolo[3,4-c]pyrrole-1,4-diyl]-alt-(2-octylnonyl)-2,1,3-benzotriazole], DPP-DTT diketopyrrolo-pyrrole-dithiophene-thienothiophene, SCLC space charge-limited conduction, DOS density of states