Phenothiazine Derivatives as Small-Molecule Organic Cathodes with Adjustable Dropout Voltage and Cycle Performance.

Compared with conventional inorganic materials, organic electrodes are competitive candidates for secondary battery cathodes due to their resourcefulness, environmental friendliness, and cost-effectiveness. Much effort is devoted at the level of chemical structure, while ignoring the impact of molecular aggregation on battery behavior. Herein, this work designs a series of organic molecules with two electrochemically active phenothiazine groups linked by different lengths of alkyl chain to regulate molecular symmetry and crystallinity. The results emphasize the equally important role of molecular aggregation and chemical structure for battery performance. Among them, 2PTZ-C7H14|Li cell exhibits the most impressive cycle and rate performance. At the high rate of 50 C, it can still deliver a capacity of 63.4 mA h g-1 and 74.5% capacity retention after 10 000 cycles. Besides, the dropout voltage of 2PTZ-C9H18|Li cell is only 52 mV, which is among the lowest reported for lithium-organic batteries to the best of the author's knowledge.

Distribution Fitting for Combating Mode Collapse in Generative Adversarial Networks.

Mode collapse is a significant unsolved issue of generative adversarial networks (GANs). In this work, we examine the causes of mode collapse from a novel perspective. Due to the nonuniform sampling in the training process, some subdistributions may be missed when sampling data. As a result, even when the generated distribution differs from the real one, the GAN objective can still achieve the minimum. To address the issue, we propose a global distribution fitting (GDF) method with a penalty term to confine the generated data distribution. When the generated distribution differs from the real one, GDF will make the objective harder to reach the minimal value, while the original global minimum is not changed. To deal with the circumstance when the overall real data is unreachable, we also propose a local distribution fitting (LDF) method. Experiments on several benchmarks demonstrate the effectiveness and competitive performance of GDF and LDF.

The Effect of Molecular Conformations and Simulated "Self-Doping" in Phenothiazine Derivatives on Room-Temperature Phosphorescence.

The research of purely organic room-temperature phosphorescence (RTP) materials has drawn great attention for their wide potential applications. Besides single-component and host-guest doping systems, the self-doping with same molecule but different conformations in one state is also a possible way to construct RTP materials, regardless of its rare investigation. In this work, twenty-four phenothiazine derivatives with two distinct molecular conformations were designed and their RTP behaviors in different states were systematically studied, with the aim to deeply understand the self-doping effect on the corresponding RTP property. While the phenothiazine derivatives with quasi-axial (ax) conformation presented better RTP performance in aggregated state, the quasi-equatorial (eq) ones were better in isolated state. Accordingly, the much promoted RTP performance was achieved in the stimulated self-doping state with ax-conformer as host and eq-one as guest, demonstrating the significant influence of self-doping on RTP effect.