DFT Modeling of Novel Donor-Acceptor (D-A) Molecules Incorporating 3-hexylthiophene (3HT) for Bulk Heterojunction Solar Cells

The versatile family of molybdenum oxides: synthesis, properties, and recent applications

The family of molybdenum oxides has numerous advantages that make them strong candidates for high-value research and various commercial applications. The variation of their multiple oxidation states allows their existence in a wide range of compositions and morphologies that converts them into highly versatile and tunable materials for incorporation into energy, electronics, optical, and biological systems. In this review, a survey is presented of the most general properties of molybdenum oxides including the crystalline structures and the physical properties, with emphasis on present issues and challenging scientific and technological aspects. A section is devoted to the thermodynamical properties and the most common preparation techniques. Then, recent applications are described, including photodetectors, thermoelectric devices, solar cells, photo-thermal therapies, gas sensors, and energy storage.

Computational Design of Crescent Shaped Promising Nonfullerene Acceptors with 1,4-Dihydro-2,3-quinoxalinedione Core and Different Electron-withdrawing Terminal Units for Photovoltaic Applications

This study aims to design a series of nonfullerene acceptors (NFAs) for photovoltaic applications having 1,4-dihydro-2,3-quinoxalinedione fused thiophene derivative as the core unit and 1,1-dicyanomethylene-3-indanone (IC) derivatives and different π-conjugated molecules other than IC as terminal acceptor units. All the investigated NFAs are found air-stable as the computed highest occupied molecular orbitals (HOMOs) are below the air oxidation threshold (ca. -5.27 eV vs saturated calomel electrode). The studied NFAs can act as potential nonfullerene acceptor candidates as they are found to have sufficient open-circuit voltage (V_oc) and fill factor (FF) ranging from 0.62 to 1.41 V and 83%-91%, respectively. From the anisotropic mobility analysis, it is noticed that the studied NFAs except dicyano-rhodanine terminal unit containing NFA, exhibit better electron mobility than the hole mobility, and therefore, they can be more promising electron transporting acceptor materials in the active layer of an organic photovoltaic cell. From the optical absorption analysis, it is noted that all the designed NFAs have the maximum absorption spectra ranging from 597 nm-730 nm, which lies in the visible region and near-infrared (IR) region of the solar spectrum. The computed light-harvesting efficiencies for the PM6 (thiophene derivative donor selected in our study):NFA blends are found to lie in the range of 0.96-0.99, which indicates efficient light-harvesting by the PM6:NFA blends during photovoltaic device operation.

Theoretical investigations about the effect of electron-withdrawing groups on proprieties of A-π-D-π-A type small molecules donor for organic solar cells

Taking the reporting donor SM0 as reference, three new A-π-D-π-A type small molecules donors (SM1, SM2, and SM3) were designed via replacing acceptor moieties. The molecular proprieties affecting the cell performance, such as, frontier molecular orbital, open circuit voltage (V_oc), absorption spectrum, vertical and adiabatic ionization potential, vertical and adiabatic electronic affinity, and energy driving force ΔE_L-L were investigated through the density functional theory (DFT) and the time dependent density functional theory (TD-DFT). All new designed molecules exhibit reduced energy gap, show a red shift absorption band, small energy binding E_b, moderate V_oc, and improve the creation of hole and electron as compared to SM0, which demonstrate that these new designed molecules could be used as a promising donors materials for organic solar cell. Additionally, the three new designed molecules present a larger amount charge transfer q_CT, a longer length charge transfer D_CT than SM0 and have a smaller reorganization energy of hole λ(h) which improve the charge carrier mobilities.