Simple and interpretable data-driven descriptor accurately predicts the synthesizability of single and double perovskites.

Long-range corrected (range-separated hybrid) functionals represent a relatively new class of functionals for generalized Kohn-Sham theory that have proven to be very successful, for instance, when it comes to predicting ionization potentials and energy gaps for a wide range of molecules and solids. The results obtained from long-range corrected density functional theory approaches can be improved dramatically, if the range-separation parameter (ω) is optimized for each system separately. In this work, we have optimized ω for a series of π-conjugated molecular systems of increasing length by forcing the resulting functionals to obey the ionization potential-theorem, i.e., that their highest occupied eigenvalue be equal to the ΔSCF ionization potential. The optimized ω values are observed to vary substantially from their default values for the functionals. For highly conjugated chains such as oligoacenes and polyenes, we find that the characteristic length scale of the range-separation, i.e., 1/ω, grows almost linearly with the number of repeat units, for saturated alkane chains, however, 1/ω quickly saturates after 5-6 repeat units. For oligothiophenes, we find that 1/ω grows linearly for the shorter oligomers but then saturates at around 10 repeat units. Our results point to a close relation between the optimal range-separation parameter and the degree of conjugation in the system.

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Noncovalent intermolecular interactions, which can be tuned through the toolbox of synthetic chemistry, determine not only the molecular packing but also the resulting electronic, optical, and mechanical properties of materials derived from π-conjugated molecules, oligomers, and polymers. Here, we provide an overview of the theoretical underpinnings of noncovalent intermolecular interactions and briefly discuss the computational chemistry approaches used to understand the magnitude of these interactions. These methodologies are then exploited to illustrate how noncovalent intermolecular interactions impact important electronic propertiessuch as the electronic coupling between adjacent molecules, a key parameter for charge-carrier transportthrough a comparison between the prototype organic semiconductor pentacene with a series of N-substituted heteropentacenes. Incorporating an understanding of these interactions into the design of organic semiconductors can assist in developing novel materials systems from this fascinating molecular class.

Correlations among the molecular structure, crystal structure, electronic structure, and charge-carrier transport phenomena have been derived from six congeners (2–7) of rubrene (1). The congeners were synthesized via a three-step route from known 6,11-dichloro-5,12-tetracenedione. After crystallization, their packing structures were solved using single-crystal X-ray diffraction. Rubrenes 5–7 maintain the orthorhombic features of the parent rubrene (1) in their solid-state packing structures. Control of the packing structure in 5–7 provided the first series of systematically manipulated rubrenes that preserve the π-stacking motif of 1. Density functional theory calculations were performed at the B3LYP/6-31G(d,p) level of theory to evaluate the geometric and electronic structure of each derivative and reveal that key properties of rubrene (1) have been maintained. Intermolecular electronic couplings (transfer integrals) were calculated for each derivative to determine the propensity for charge-carrier transport. For rubrenes 5–7, evaluations of the transfer integrals and periodic electronic structures suggest these derivatives should exhibit transport characteristics equivalent to, or in some cases improved on, those of the parent rubrene (1), as well as the potential for ambipolar behavior. Single-crystal field-effect transistors were fabricated for 5–7, and these derivatives show ambipolar transport as predicted. Although device architecture has yet to be fully optimized, maximum hole (electron) mobilities of 1.54 (0.28) cm2 V–1 s–1 were measured for rubrene 5. This work lays a foundation to improve our understanding of charge-carrier transport phenomena in organic single-crystal semiconductors through the correlation of designed molecular and crystallographic changes to electronic and transport properties.