Thermoelectric performance of(AgBiTe_(2))_(1-x)(SnTe)_(x) with stable cubic enabled by enhanced configurational entropy

ABX_(2)(A=Ag,Na,Cu;B=Sb,Bi;X=S,Se,Te)(GroupsⅠ-Ⅴ-Ⅵ_(2))compounds,which are all characterized by the ultralow lattice thermal conductivity because of their strong lattice anharmonicity caused by lone-pair electrons,have aroused wide attention in thermoelectric community.The practical application of thermoelectric devices usually requires both the compatible n-type and p-type materials simultaneously.However,most ofⅠ-Ⅴ-Ⅵ_(2)compounds are intrinsic p-type semiconductors,lacking their n-type counterparts for thermoelectrics.Herein,in this work,we increase the configuration entropy of AgBiTe_(2)by alloying SnTe,in order to stabilize the cubic phase at room temperature.With further optimization of thermal and electrical performance,the thermoelectric performance could be improved simultaneously in both n-and p-type(AgBiTe_(2))_(1-x)(SnTe)_(x)(x=0.3,0.4)solid solutions.Finally,p-type compound with the nominal composition of(AgBi_(0.99)Cd_(0.01)Te_(2))_(0.6)(SnTe)_(0.4)and n-type of(AgBiTe_(2))_(0.7)(SnTe)_(0.3)~Br 6%show the maximum zT of~0.33 and~0.21,at 381 and 423 K,respectively.

Enhanced thermoelectric performance of Cu_(2)SnSe_(3) via synergistic effects of Cd-doping and CuGaTe_(2) alloying

In this work,we show significantly enhanced thermoelectric performance in Cu_(2) SnSe_(3) via a synergistic effect of Cd-doping and CuGaTe_(2) alloying in the temperature range of 300-823 K.Both the electron and phonon transport properties can be simultaneously regulated by Cd doping at Sn site,leading to a higher quality factor.Meanwhile,a maximum figure of merit(zT) value of ~0.68 was obtained for Cu_(2) Sn_(0.93)Cd_(0.07)Se_(3) sample at823 K,which is about four times higher than that of the pristine sample(zT=0.18 at 773 K).Furthermore,Cu_(2) Sn_(0.93)Cd_(0.07)Se_(3) was alloyed with CuGaTe_(2) to reduce the lattice thermal conductivity in the high-temperature region.Consequently,a further enhanced zT value(0.77,823 K) was achieved in the(Cu_(2) Sn_(0.93)Cd_(0.07)Se_(3))_(0.94)(CuGaTe_(2))_(0.06) sample,with a high average zT(zT_(ave)) value of0.30 between 300 and 823 K.These results demonstrate that Cd-doping combined with CuGaTe2 alloying could be an effective method to enhance zT values of Cu_(2) SnSe_(3) based compounds.

Status and Trends of GAP Base Construction of Chinese Materia Medica in Guangdong Province

It is one of the key points for modernization and internationalization of traditional Chinese medicines to construct the Good Agricultural Practice (GAP) base of Chinese materia medica (CMM). GAP helps to minimize contamination and improve the quality of CMM during the plantation and the production of Chinese crude drugs. In this article, the status and development of CMM production bases of GAP in Guangdong Province, China, are presented. The suggestions upon the problems during the development of GAP for Chinese crude drugs are also provided.