Virtual screening is becoming a ground-breaking tool for molecular discovery due to the exponential growth of available computer time and constant improvement of simulation and machine learning techniques. We report an integrated organic functional material design process that incorporates theoretical insight, quantum chemistry, cheminformatics, machine learning, industrial expertise, organic synthesis, molecular characterization, device fabrication and optoelectronic testing. After exploring a search space of 1.6 million molecules and screening over 400,000 of them using time-dependent density functional theory, we identified thousands of promising novel organic light-emitting diode molecules across the visible spectrum. Our team collaboratively selected the best candidates from this set. The experimentally determined external quantum efficiencies for these synthesized candidates were as large as 22%.

Singlet fission can split a high energy singlet exciton and generate two lower energy triplet excito ns. This process has shown near 200 percent triplet exciton yield. Sensitizing solar cells with singlet fission material, it can potentially increase the power conversion efficiency limit from 29 percent to 35 percent. Singlet fission in the tetracene is known to be efficient, and the energy of the triplet excitons are energetically matched to the silicon bandgap. In this work, we designed an optical measurement with an external magnetic field to determine the efficiencies of triplet exciton transfer from tetracene to silicon. Using this method, we have found that a passivation layer of 8 angstroms of hafnium oxynitride on silicon allows efficient triplet exciton transfer around 133 percent.

Lead halide-based perovskite thin films have attracted great attention due to the explosive increase in perovskite solar cell efficiencies. The same optoelectronic properties that make perovskites ideal absorber materials in solar cells are also beneficial in other light-harvesting applications and make them prime candidates as triplet sensitizers in upconversion via triplettriplet annihilation in rubrene. In this contribution, we take advantage of long carrier lifetimes and carrier diffusion lengths in perovskite thin films, their high absorption cross sections throughout the visible spectrum, as well as the strong spin-orbit coupling owing to the abundance of heavy atoms to sensitize the upconverter rubrene. Employing bulk perovskite thin films as the absorber layer and spin-mixer in inorganic/organic heterojunction upconversion devices allows us to forego the additional tunneling barrier owing from the passivating ligands required for colloidal sensitizers. Our bilayer device exhibits an upconversion efficiency in excess of 3% under 785 nm illumination.

Multiexcited‐state phenomena are believed to be the root cause of two exigent challenges in organic light‐emitting diodes; namely, efficiency roll‐off and degradation. The development of novel strategies to reduce exciton densities under heavy load is therefore highly desirable. Here, it is shown that triplet exciton lifetimes of thermally activated delayed‐fluorescence‐emitter molecules can be manipulated in the solid state by exploiting intermolecular interactions. The external heavy‐atom effect of brominated host molecules leads to increased spin–orbit coupling, which in turn enhances intersystem crossing rates in the guest molecule. Wave function overlap between the host and the guest is confirmed by combined molecular dynamics and density functional theory calculations. Shorter triplet exciton lifetimes are observed, while high photoluminescence quantum yields and essentially unaltered emission spectra are maintained. A change in the intersystem crossing rate ratio due to increased dielectric constants leads to almost 50% lower triplet exciton densities in the emissive layer in the steady state and results in an improved onset of the photoluminescence quantum yield roll‐off at high excitation densities. Efficient organic light‐emitting diodes with better roll‐off behavior based on these novel hosts are fabricated, demonstrating the suitability of this concept for real‐world applications.

Figure 1. Homoconjugation and dihedral angle tuning. Scheme 1. Syntheses of Compounds 2−6 Communication pubs.acs.org/cm