Kategoriak: All - absorption - fluorescence - temperature - solvent

arabera Liwei Wang 5 years ago

326

Bulk results and question

The text discusses the behavior of a polymer dissolved in various solvents, with a particular focus on hexane, chloroform, and ethanol. It addresses the polymer's photophysical properties such as absorption and fluorescence at different wavelengths (

Bulk results and question

Bulk results and question

Questions

Can we use the anisotropy phase change in solution sample to check the results? film?
why the 60% ethanol chloroform mixture would have absorption in long range, but the change is not linear, why?
might caused by the conformation of liquid crystal Ma, T., Song, N., Liu, B., Ren, J., Zhang, H., & Lu, D. (2019). Effect of External Electric-Field on Poly [(9, 9-dioctylfuorenyl-2, 7-diyl)-alt-co-(bithiophene)](F8T2) Chain Orderness, Morphology and Carrier Mobility in Different Condensation Process. The Journal of Physical Chemistry C.

why the conformation is a relative stable? why it does not change by shaking? if it is caused by different distance? then, what is the repulsion of the chain comes from???

If measure the average molecular size in the solvent, it might increase then decrease again.

the spectrum comparison between cryogenic and room temperature on MeTHF and Chloroform is different, it seems that it barely show J aggregate form under 400 nm excitation or chloroform situation
why the film with similar spectrum as hexane dissolved sample show super short lifetime that even shorter than the solvent situation?
similar to the lifetime trend in P3HT

It may from efficient(ultrafast) interchain exciton dissociation with eventual contribution of singlet-singlet annhilation. Alternatively, aggergates could provide phonon modes capable of substantially increasing internal conversion, which cause the strong fluorescence quenching in film. (something as twistng motion of the molecular chain) Ferreira, B., da Silva, P. F., Seixas de Melo, J. S., Pina, J., & Maçanita, A. (2012). Excited-state dynamics and self-organization of poly (3-hexylthiophene)(P3HT) in solution and thin films. The Journal of Physical Chemistry B, 116(8), 2347-2355.

polymer dissolved in hexane

Hex 400 nm fit
Hex 488 nm fit
compare with other bad solvent
abs with air blank

film

fluo 488 77K
Fluo 488

solvent

Chloroform and ethanol
cryogenic and room temperature control
lifetime

normalized

not normalized

Chloroform and Hexane
Lifetime

concentration dependent

wavelength dependent

Franck condon analysis

CH 400 nm fit

QY without correction

488 nm

400 nm

PLE
Fluo

488 77K

488 rm

400

ABS