Abstract. Growing evidence suggests that the size-resolved mixing state of carbon-containing particles is very critical in determining their optical properties, atmospheric lifetime, and impact on the environment. However, still little is known about the mixing state of particles in the urban area of the Pearl River Delta (PRD) region, China. To investigate the mixing state of submicron carbon-containing particles, measurements were carried out during spring and fall periods of 2010 using a single-particle aerosol mass spectrometer (SPAMS). Approximately 700 000 particles for each period were detected. This is the first report on the size-resolved mixing state of carbon-containing particles by direct observations in the PRD region. Cluster analysis of single-particle mass spectra was applied to identify carbon-containing particle classes. These classes represented ~80% and ~90% of all the detected particles for spring and fall periods, respectively. Carbon-containing particle classes mainly consisted of biomass/biofuel burning particles (Biomass), organic carbon (OC), fresh elemental carbon (EC-fresh), internally mixed OC and EC (ECOC), internally mixed EC with sulfate (EC-Sulfate), vanadium-containing ECOC (V-ECOC), and amines-containing particles (Amine). In spring, the top three ranked carbon-containing particle classes were ECOC (26.1%), Biomass (23.6%) and OC (10%), respectively. However, the fraction of Biomass particles increased remarkably and predominated (61.0%), while the fraction of ECOC (3.0%) and V-ECOC (0.1%) significantly decreased in fall. To highlight the influence of monsoon on the properties of carbon-containing particles in urban Guangzhou, their size distributions, mixing state, and aerosol acidity were compared between spring and fall seasons. In addition, a case study was also performed to investigate how the formation of fog and haze influenced the mixing state of carbon-containing particles. These results could improve our understanding of the mixing state of carbon-containing particles, and may also be helpful in modeling the climate forcing of aerosol in the PRD region.

AgSbSe 2 is a promising thermoelectric (TE) ptype material for applications in the middle-temperature range. AgSbSe 2 is characterized by relatively low thermal conductivities and high Seebeck coefficients, but its main limitation is moderate electrical conductivity. Herein, we detail an efficient and scalable hot-injection synthesis route to produce AgSbSe 2 nanocrystals (NCs). To increase the carrier concentration and improve the electrical conductivity, these NCs are doped with Sn 2+ on Sb 3+ sites. Upon processing, the Sn 2+ chemical state is conserved using a reducing NaBH 4 solution to displace the organic ligand and anneal the material under a forming gas flow. The TE properties of the dense materials obtained from the consolidation of the NCs using a hot pressing are then characterized. The presence of Sn 2+ ions replacing Sb 3+ significantly increases the charge carrier concentration and, consequently, the electrical conductivity. Opportunely, the measured Seebeck coefficient varied within a small range upon Sn doping. The excellent performance obtained when Sn 2+ ions are prevented from oxidation is rationalized by modeling the system. Calculated band structures disclosed that Sn doping induces convergence of the AgSbSe 2 valence bands, accounting for an enhanced electronic effective mass. The dramatically enhanced carrier transport leads to a maximized power factor for AgSb 0.98 Sn 0.02 Se 2 of 0.63 mW m −1 K −2 at 640 K. Thermally, phonon scattering is significantly enhanced in the NC-based materials, yielding an ultralow thermal conductivity of 0.3 W mK −1 at 666 K. Overall, a record-high figure of merit (zT) is obtained at 666 K for AgSb 0.98 Sn 0.02 Se 2 at zT = 1.37, well above the values obtained for undoped AgSbSe 2 , at zT = 0.58 and state-of-art Pb-and Te-free materials, which makes AgSb 0.98 Sn 0.02 Se 2 an excellent p-type candidate for medium-temperature TE applications.

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As the thickness of silicon solar cells becomes thinner, the cells are susceptible to bow because of the metallization of metal and semiconductor on the front and rear contact. In this work, the thickness impacts of aluminum and silicon on bow of the solar cell have been investigated with the perspective of deformation and strain.

The BSF of mono-crystal silicon cell is studied in this paper. It simply states the principle and formation process of BSF, and studies the evenness of BSF. In the experiment, we analyze BSF formed by taking different sintering temperature, heating rate and setting different time, develop by chemical reagent and observe at high magnification scope, analyze and get the optimal parameters of forming even BSF and further improve conversion efficiency of silicon chips.