Output power of thermoelectric generators depends on device engineering minimizing heat loss as well as inherent material properties. However, the device engineering has been largely neglected due to the limited flat or angular shape of devices. Considering that the surface of most heat sources where these planar devices are attached is curved, a considerable amount of heat loss is inevitable. To address this issue, here, we present the shape-engineerable thermoelectric painting, geometrically compatible to surfaces of any shape. We prepared Bi2Te3-based inorganic paints using the molecular Sb2Te3 chalcogenidometalate as a sintering aid for thermoelectric particles, with ZT values of 0.67 for n-type and 1.21 for p-type painted materials that compete the bulk values. Devices directly brush-painted onto curved surfaces produced the high output power of 4.0 mW cm−2. This approach paves the way to designing materials and devices that can be easily transferred to other applications.

We report a strategy toward the synthesis of colloidal nanocrystals capped with inorganic molybdenum and tungsten sulfide ligands. MoS4(2-) and WS4(2-) thiometalates were utilized to replace organic ligands capping a wide range of nanocrystals such as metals, semiconductors, and well-conserved primary properties of nanocrystals in polar media. Especially, MoS4(2-)- and WS4(2-)-capped CdSe nanocryatals showed the dramatic enhancement of photoluminescence properties by the photo-oxidation treatment, which originated from the preferential formation of MoSxOy layers on the CdSe surface. The highest quantum yield reached up to 51%. Furthermore, we studied the charge-transport properties of MoS4(2-)-capped PbS nanocryatals by the fabrication of a field-effect transistor and photodetectors. Finally, MoS4(2-)- and WS4(2-)-capped nanocrystals were used for the production of two-dimensional MoS2 and WS2 thin layers on nanostructures by heat treatment. Such versatility of these thiometalate ligands offers an additional degree of control over the functionality of nanocrystals for optoelectronic and catalytic applications.

Thermoelectric (TE) technologies offer promising means to enhance fossil energy efficiencies by generating electricity from waste heat from industrial or automobile exhaust gases. For these applications, thermoelectric modules should be designed from the perspective of system integration for efficient heat transfer, system simplification, and low processing cost. However, typical thermoelectric modules manufactured by traditional processes do not fulfil such requirements, especially for exhaust pipes. Hence, a 3D‐printing method for PbTe thermoelectric materials is reported to design high‐performance power‐generating TE tubes. The electronic doping‐induced surface charges in PbTe particles are shown to significantly improve the viscoelasticities of inks without additives, thereby enabling precise shape and dimension engineering of 3D bulk PbTe with figures of merit of 1.4 for p‐type and 1.2 for n‐type materials. The performance of the power‐generating TE tube fabricated from 3D‐printed PbTe tubes is demonstrated experimentally and computationally as an effective strategy to design system‐adaptive high‐performance thermoelectric generators.

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Crystalline red phosphorus has very recently emerged as a stable and cost-effective semiconductor material. However, despite its potentiality in electronics and optoelectronics, the widespread application of this material is still hampered by the limited synthetic route of the ampoule-based chemical vapor deposition that critically requires mineralizing agents. To address this issue, we report the chemical synthesis of soluble polyphosphide precursors that serve as inks for the solutionprocessed fabrication of crystalline fibrous phosphorus thin films. The purified polyphosphide precursor formed crystalline fibrous phosphorus via thermal annealing at a temperature as low as 250 °C without any mineralizing agents. This anionic polyphosphide functioned as a surface-capping ligand for nanoparticles including metals, semiconductors, and magnets. Therefore, the study investigates the possibility of solution-processed fibrous phosphorus thin films as active channel layers in fieldeffect transistors as well as photodetectors and demonstrates their initial performances on the charge-transport and photoresponsive characteristics of these devices. The effect of semiconducting PbS nanoparticles embedded in the fibrous phosphorus thin films on device performance was also studied. The synthesized polyphosphide precursor offers a vast opportunity for the facile preparation of crystalline red phosphorus and chemical design of nanoparticles.