DFT based modeling of asymmetric non-fullerene acceptors for high-performance organic solar cell

Abstract

Five new asymmetric NFA-based polymer solar cells i.e., N1-N5 are designed by doing modi cation in terminal groups of the acceptor part of experimentally synthesized reference molecule with (4,4,9,9tetramethyl-4,9 dihydroselenopheno [2',3':5,6]-s-indaceno [1,2-b] thiophene) core. Frontier molecular orbital analysis is used to study their photovoltaic and optoelectronic properties. It con rmed the electrons' transportation from the donor to the acceptor part. It stated that all molecules have a lower bandgap than R and N2 has the lowest bandgap of 2.01 eV. The molecular orbital potential analysis con rmed the electron-withdrawing properties of the terminal groups. Optical properties studies evaluated maximum absorption with transition energies. All newly designed molecules N1-N5 show higher λ max values than R i.e., in the range of 680-740 nm with N2 having the highest λ max of 735 nm and lowest transition energy of 1.69 eV. Dipole moment studies showed that N3 has a maximum dipole moment of 7-40 D with all others having comparable values. TDM plots con rmed the electron shifting from donor to acceptor region. Reorganization energy analysis showed that N1 and N3 have the lowest reorganization energy values thus giving the highest electron mobilities. V oc calculated results of all molecules N1-N5 have lower values than R when coupled with PTB7-Th donor polymer. Charge transport analysis of N2 and PTB7-Th coupled molecule con rmed the acceptor type nature of our designed molecules. Highlights 1. Asymmetric fullerene free acceptor molecules (N1-N5) are studied for organic solar cells applications.2. Signi cant lowering of energy gap with concomitant red shifting of the absorption spectra is achieved with end-group engineering.3. The acceptors molecules show lower binding energy and excellent electron and hole reorganizational energies.4. All acceptor molecules have remarkable optoelectronic properties compared to reference R.

Designing of banana shaped chromophores via molecular engineering of terminal groups to probe photovoltaic behavior of organic solar cell materials

“…RE is computed and is presented in Table 3 , to calculate reorganization energies for both electron ( λ e ) and hole ( λ h ), Eqs. ( 1 ) and ( 2 ) 48 – 51 are utilized. …”

Transition Metal-Decorated Mg12O12 Nanoclusters as Biosensors and Efficient Drug Carriers for the Metformin Anticancer Drug

“…Generally, Mg 12 O 12 and related systems have a large band gap, which is an important factor for these semiconductors, but the doping of these nanoclusters brings about the reduction in the band gap, which is fruitful for the charge transfer rate and also makes these systems valuable adsorption sites for drugs like metformin. The following equation helps compute the energy band gap. − E normalg = E LUMO − E HOMO …”

Theoretical designing of 9,9'-dicarbazole-based dye via end-group modification for indoor DSSC applications

“…TDM analysis provides insights into various aspects of electrons-holes scattering within the molecules, electronic excitation levels, and the dynamics of interactions between the parts of the molecules responsible for donating and accepting electrons [74][75][76]. To validate the behavior of molecules in excited states, we conducted TDM simulations for all the designed molecules including R, using the same DFT method.…”

“…The efficiency of DSSCs is indirectly linked to the reorganization energy levels of both electrons (λ e ) and holes (λ h ). High PCE is associated with low values of λ e and λ h [75]. The reorganizational energy data was obtained through theoretical calculations employing the MPW1PW91 level.…”