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Designing new compounds with earth-abundant constituent elements and intrinsically low thermal conductivity are crucial to the development of thermoelectric materials. In this letter, the tetragonal-structured PbSe 2 with extremely low thermal conductivity was prepared by two-step ball milling and high pressure synthesis method. Density functional theory calculation shows that the low thermal conductivity of PbSe 2 is originated from its weak interatomic bonding strength and high lattice vibration anharmonicity. We also found that the carrier concentration of PbSe 2 can be tuned effectively by Ag doping in Pb site, which leads to an enhanced figure of merit. These results indicate that PbSe 2 is a potential candidate as a thermoelectric material. • Tetragonal structured PbSe 2 was synthesized by a high-pressure method. • PbSe 2 behaves an extremal low thermal conductivity. • The carrier concentration and ZT of PbSe 2 was enhanced effectively by Ag doping. [ABSTRACT FROM AUTHOR]

• Thermoelectric oxide BiCuSeO was facile prepared by one-step high-pressure method. • The sample contains fine grains and a large number of multiscale nanoparticles. • An extremely low thermal conductivity and enhanced ZT of BiCuSeO was obtained. BiCuSeO based materials have been drawn much attention since they were found to be excellent thermoelectric materials recently. Apart from high performance, the time and energy-efficient synthesis of BiCuSeO is also essential for its commercialization. In this paper, a simple one-step high pressure method was used to quickly synthesize the copper-deficient BiCuSeO. The introduction of Cu vacancy improves the carrier concentration and power factor. Through the phonon scattering of fine grains and crystal defects caused by Cu deficiency and high pressure compression, an extremely low phonon thermal conductivity of BiCu 0.94 SeO ~ 0.3 Wm−1K−1 @ 750 K is obtained. An enhanced ZT ~ 0.87 at 750 K is obtained for BiCu 0.94 SeO. This value is twice higher than that of the original BiCuSeO, compared with the traditional time-consuming method. [ABSTRACT FROM AUTHOR]

• ABA amphiphilic triblock copolymer self-assembled into flower-like micelles. • The micelles showed excellent photo-response to irradiation time. • The photolysis rate could be adjusted by changing polymer chain lengths. • DOX-loaded micelles exhibit drug release increased obviously after UV irradiation. The photo-responsive ABA amphiphilic triblock copolymers polylactide-block-poly(ethylene glycol)-block-polylactide with o-nitrobenzyl esters as the photocleavable block-linker (defined as PLA-NB-PEG-NB-PLA), were prepared by controlled ring-opening polymerization (ROP) of D, L-lactide (D, L-LA) using two o-nitrobenzyl groups terminated polyethylene glycol as initiator. Flower-like micelles formed after these copolymers were dissolved in aqueous solution. Introduction of shortened PEG and PLA chains, although resulting in the reduction of micelle sizes, would bring about higher photolysis rate and loading efficiency of DOX. The flower-like micelles showed excellent photocleavage properties, thereby, burst release of DOX could be induced after UV irradiation, which will have potential application in biomedical materials. [ABSTRACT FROM AUTHOR]