3 research outputs found
Improving Molecular Pretraining with Complementary Featurizations
Molecular pretraining, which learns molecular representations over massive
unlabeled data, has become a prominent paradigm to solve a variety of tasks in
computational chemistry and drug discovery. Recently, prosperous progress has
been made in molecular pretraining with different molecular featurizations,
including 1D SMILES strings, 2D graphs, and 3D geometries. However, the role of
molecular featurizations with their corresponding neural architectures in
molecular pretraining remains largely unexamined. In this paper, through two
case studies -- chirality classification and aromatic ring counting -- we first
demonstrate that different featurization techniques convey chemical information
differently. In light of this observation, we propose a simple and effective
MOlecular pretraining framework with COmplementary featurizations (MOCO). MOCO
comprehensively leverages multiple featurizations that complement each other
and outperforms existing state-of-the-art models that solely relies on one or
two featurizations on a wide range of molecular property prediction tasks.Comment: 24 pages, work in progres
Surface Passivation with Selected Phosphine Oxide Molecules for Efficient PureâBlue MixedâHalide Perovskite Quantum Dot LightâEmitting Diodes
Abstract Passivation of defects in halide perovskite using phosphine oxide or alkylâphosphonate has recently obtained a few remarkable achievements. However, effective application of phosphine oxide or alkyâphosphonate in passivating perovskite quantum dots (QDs) are seldom reported due to solubility issue or difficulty of amount control. In this work, two bifunctional organic molecules containing phosphine oxide groups, 2,4,6âTris[3â(diphenylphosphinyl)phenyl]â1,3,5âtriazine (POâT2T) and 2,7âbis(diphenylphosphoryl)â9,9â˛âspirobifluorene (SPPO13), are deposited on QDs films by thermal evaporation. The molecules, both as passivation agents as well as electron transporting materials, exhibit stark contrast in passivating QDs and in lightâemitting diodes (LEDs) performance. A competition between charge transfer and defect passivation between the QDs and the molecules is proposed. In film, electron transfer from the QDs to POâT2T dominates and quench the QDs, while the passivation effect of POâT2T on the QDs dominates in driving device and enhances luminance of the LEDs. In contrast, passivation effect of SPPO13 on the QDs dominates both in films and in LEDs. A maximum EQE of 2.67% is obtained for the pureâblue LED based on SPPO13âpassivated QDs films. This work provides a guide on the selection of passivation agents based on phosphine oxide and a promising passivation method for highâefficient perovskite QD LEDs