Conventional chemical doping processes for conjugated polymers (CPs) often degrade the film morphology or cause unsatisfactory doping efficiency owing to the aggregation formation between charged species or insufficient dopant diffusion. In this work, a new strategic doping method, "hybrid doping," is suggested for maximizing the doping efficiency of CPs without hampering the surface morphology of the CP films. The advantage of hybrid doping is that it combines mixture blending and sequential soaking processes. Based on systemic characterizations including spectroscopic, structural, and electrical analyses, it is revealed that hybrid doping enables whole area doping for the crystalline and amorphous regions of CP films, and thus an unprecedentedly high electrical conductivity of up to 81.5 and 639.1 S cm −1 , for poly(3-hexylthiophene) P3HT and poly (2-([2,2′-bithiophen]-5-yl)-3,8-difluoro-5,10-bis(5octylpentadecyl)-5,10-dihydroindolo [3,2-b]indole) (PIDF-BT), respectively, is achieved. Furthermore, the exceptional electrical conductivity compensates a reduced Seebeck coefficient, resulting in excellent power factors up to 26.8 and 76.1 μW m −1 K −2 for thermoelectric devices based on doped-P3HT and PIDF-BT films, respectively, which is among the highest levels for semiconducting CPs. Hybrid doping is a strategic approach for the simultaneous optimization of electrical conductivity and thermoelectric properties of various CPs.

In modern society, high-quality material development and a large stable supply are key to perform frontier research and development. However, there are negative issues to address to utilize high-quality resources with a large stable supply for research, such as economic accessibility, commercialization, and so on. One of the cutting-edge research fields, perovskite-related research, usually requires high-quality chemicals with outstanding purity (>99%). We developed an economically feasible PbI2 precursor with around 1/20 cost-down for perovskite/perovskite quantum dots through recrystallization and/or hydrothermal purification. Following the methodology, the quantum dots from both as-prepared and purified PbI2 demonstrated identical photophysical properties, with a photoluminescence quantum yield (PLQY) of 52.61% using the purified PbI2 vs. 45.83% PLQY using commercial PbI2. The role of hydrothermal energy was also checked against the problematic PbI2, and we checked whether the hydrothermal energy could contribute to the hindrance of undesired particle formation in the precursor solution, which enables them to form enlarged grain size from 179 ± 80 to 255 ± 130 nm for higher photoconversion efficiency of perovskite solar cells from 14.77 ± 1.82% to 15.18 ± 1.92%.

Electron donor (D)-acceptor (A)-type conjugated polymers (CPs) have emerged as promising semiconductor candidates for organic field-effect transistors. Despite their high charge carrier mobilities, optimization of electrical properties of D-A-type CPs generally suffers from complicated post-deposition treatments such as high-temperature thermal annealing or solvent-vapor annealing. In this work, we report a high-mobility diketopyrrolopyrrole-based D-A-type CP nanowires, self-assembled by a simple but very effective solvent engineering method that requires no additional processes after film deposition. In situ grown uniform nanowires at room temperature were shown to possess distinct edge-on chain orientation that is beneficial for lateral charge transport between source and drain electrodes in FETs. FETs based on the polymer nanowire networks exhibit impressive hole mobility of up to 4.0 cm V s. Moreover, nanowire FETs showed excellent operational stability in high temperature up to 200 °C because of the strong interchain interaction and alignment.

Herein, we developed a near-infrared (NIR) fluorescent probe for mitochondrial staining based on the NIR fluorochrome, silicon-rhodamine. The hydrophobicity of the fluorescent core was systematically modified by conjugation with 10 different commercial amines. The resulting fluorescent compounds exhibited similar photophysical properties but diverse hydrophobicity. We identified the optimal level of hydrophobicity associated with high mitochondrial targeting efficiency. In particular, the SiR-Mito 8 probe provided excellent mitochondrial staining and successfully differentiated the live Hep3B cancer cells from normal L02 cells in vitro.

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