High performance, fullerene-free organic photodiodes based on a solution processable indigo: supporting information

1. Experimental section
Material synthesis
Scheme S1. Conditions and reagents
Figure S1. 1H NMR spectrum of indigo 3
Figure S2. 13C NMR spectrum of indigo 3
Thermal, electrochemical and photophysical properties
Figure S3. TGA trace of 3
Figure S4. DSC traces of 3
Figure S5. Cyclic voltammogram of indigo 3
Figure S6. Absorption and emission spectra of a neat film of 3
PL quenching study
Table S1. Summary of PLQY quenching results

2. Charge mobility and morphorogy studies
SCLC mobility
Figure S7: Dark-current densities and SCLC fitting in electron-only and hole-only diode structures
OFET mobility
Figure S8. Field effect mobility was calculated in OFET geometry
Figure S9. OFET output charcteristics of P3HT:3 blend films in hole accumulation mode
Table: S2: Summary of electron and hole mobilities measured for neat 3 and blend films
Morphorogy study
Figure S10. AFM images of neat films of P3HT and 3, and P3HT:3 (1:1) blend films.

3. Photodiode properties
Figure S11. Temperature dependent dark current density
Figure S12. Noise Equivalent Power (NEP) trends
Figure S13. Noise equivalent power (NEP) trends for the OPDs by frequency
Figure S14. Calculated specific detectivity (D*) trends for the OPD by frequency

4. Photovoltaic and control devices performance
Photovoltaic device performance
Figure S15. J–V characteristics of the photovoltaic cells using P3HT:3 (1:1 by weight, 500 nm)
Table S3. Summary of the photovoltaic devices (ITO/PEIE/P3HT:3/MoO3/Ag)
Influence of indigo 3 on device performance: control devices
Figure S16. Device characteristics of the control device (i.e., without 3)
Table S4. Summary of the control devices (i.e., without 3)

5. Stability study
Air stability of indigo 3
Figure S17. Absorption spectra of freshly prepared and 90 days old pristine films of 3.
Device stability
Figure S18. Comparison of current density between freshly prepared and 180 days old devices.
Table S5. Comparison of solar cell performance between freshly prepared and 180 days old devices.

6. Performance comparison of non‒fullerene and/or indigo‒based photodiodes
Table S6. Performance comparison of non-fullerene and/or indigo-based photodiodes