A Facile Solution Engineering of PEDOT:PSS-Coated Conductive Textiles for Wearable Heater Applications.

To enable highly conductive electronic textiles (E-textiles), we herein demonstrate a simple solution treatment of poly (3,4-ethylenedioxythiophene): poly (styrene sulfonate) (PEDOT:PSS)-coated textiles by dimethyl sulfoxide (DMSO) and methanol. The subsequent solution engineering of DMSO and methanol not only enhances crystallization of PEDOT chains but also the contact for PEDOT:PSS to the fibers. Additionally, the methanol dipping effectively removes the insulating PSS part from the conductive PEDOT chains, which contributes to subsequently reduced sheet resistance of less than 3 Ω/sq of the conductive textiles. Joule heating property of the highly conductive textiles achieves the maximum temperature with the temperature reaching 133 °C at a low applied voltage of 3 V within 20 s, which promises highly conductive E-textiles as multi-functional wearable heater applications.

Facile Post Treatment of Ag Nanowire/Polymer Composites for Flexible Transparent Electrodes and Thin Film Heaters.

Typical polyol-based synthesis of silver nanowire employs insulating polymer as a surfactant for the silver nanowire growth, which limits direct contact between each nanowire and thus its optoelectronic properties. We herein demonstrate that a simple solvent treatment effectively removes the insulating polymer around Ag NWs, leading to significantly decreased sheet resistance (~12 Ω/sq) with an increased transmittance (81% @ T550), as compared to other post-treatments. We successfully demonstrate the transparent film heaters using the solvent-treated Ag NWs network, which rapidly exhibited 150 °C under a bias of 5 V. Flexible film heaters on plastic substrate is also demonstrated, suggesting a great potential of the solvent treatment process of Ag NWs for flexible transparent electrode and film heater applications.

Effective Dark Current Suppression for High-Detectivity Organic Near-Infrared Photodetectors Using a Non-Fullerene Acceptor.

Near-infrared organic photodetectors (NIR OPDs) have attracted considerable attention because of their inherent advantages such as a tailorable light absorption property, low-cost fabrication, compatibility with flexible substrates, and room-temperature operation. In particular, the development of NIR detection between 900 and 950 nm is crucial for noise-free communication in ambient environments. In this work, we demonstrate high-detectivity NIR OPDs at 900-950 nm by employing a non-fullerene acceptor (ITIC) used with an NIR-absorbing conjugated polymer (PNIR) for bulk heterojunction (BHJ), which significantly suppressed dark current. Systemic characterizations including electrical, structural, and morphological analyses revealed that ITIC effectively reduces charge recombination during the operation of the OPDs under NIR illumination, resulting in a dark current reduction and high detectivity of over 3.2 × 1011 Jones at 900-950 nm. The results presented here demonstrate that utilizing a non-fullerene acceptor for BHJ-type NIR OPDs is evidently a strategic approach for the simultaneous achievement of the low dark current and high-detectivity of NIR OPDs.

Methylammonium Iodide-Mediated Controlled Crystal Growth of CsPbI2Br Films for Efficient and Stable All-Inorganic Perovskite Solar Cells.

A high-quality perovskite film is a key aspect contributing to high photovoltaic performance of all-inorganic perovskite solar cells. We herein demonstrate that the addition of methylammonium iodide (MAI) influences effectively both the tailored film morphology and precise crystal growth to construct high-quality CsPbI2Br films. It is found that an MAI additive retards the crystallization kinetics to control the inorganic perovskite films to form a highly crystalline α-CsPbI2Br structure consisting of microsized grains with reduced defect density. The optimal MAI additive (10 wt %) achieves a power conversion efficiency (PCE) of 10.40% for the CsPbI2Br-based all-inorganic perovskite solar cells, which is >30% enhancement from 6.95% of the pristine one. The solar cells employing the MAI additive possess high operational and thermal stability, retaining >70% of the original PCE after aging for 1500 h in ambient atmosphere and under continuous heating at 85 °C for 30 h, respectively. The photovoltaic performance with an indoor light source was also examined using a white light-emitting diode (6500 K, 1000 lux), showing promising PCEs of 23.51% with a stabilized power output of 21.15%.