I have been trying to use Excimontec to study exciton diffusion in nonfullerene acceptor materials. First I used the dynamic test to reproduce the transients obtained from the pump-probe experiments. With appropriate choice of simulation parameters, such as the hopping rates, the energetic disorder, and the exciton lifetime, the experimental transients can be well reproduced. Then with these parameters I run the exciton diffusion test to calculate the diffusion lengths. However the results turn out to be much larger than the ones obtained by directly fitting the experimental transients. An extreme case is the NFA material IT4F, the calculated value is 48 nm while the experimental value is 27nm. For other cases, I find that the calculated value divided by $\sqrt{2}$ can be very close to the experimental value. But we cannot explain this $\sqrt{2}$ factor. It might be somehow related to the algorithm. Can you explain more about the algorithm in the User Manual? One question is that if the $L_d$ is calculated by first reaction algorithm directly, or the diffusion constant $D$ is calculated, and $L_d$ is obtained by $L_d=\sqrt{2dD\tau}$. Thank you!
I have been trying to use Excimontec to study exciton diffusion in nonfullerene acceptor materials. First I used the dynamic test to reproduce the transients obtained from the pump-probe experiments. With appropriate choice of simulation parameters, such as the hopping rates, the energetic disorder, and the exciton lifetime, the experimental transients can be well reproduced. Then with these parameters I run the exciton diffusion test to calculate the diffusion lengths. However the results turn out to be much larger than the ones obtained by directly fitting the experimental transients. An extreme case is the NFA material IT4F, the calculated value is 48 nm while the experimental value is 27nm. For other cases, I find that the calculated value divided by$\sqrt{2}$ can be very close to the experimental value. But we cannot explain this $\sqrt{2}$ factor. It might be somehow related to the algorithm. Can you explain more about the algorithm in the User Manual? One question is that if the $L_d$ is calculated by first reaction algorithm directly, or the diffusion constant $D$ is calculated, and $L_d$ is obtained by $L_d=\sqrt{2dD\tau}$ . Thank you!