Fig. 1
Synthesis and characterization of biological synthesized tellurium (Bio-Te). a Synthesis scheme of tellurium nanocrystals by anaerobic bacteria, Bacillus selenitireducens. b Image of Bio-Te crystalline nano-flake taken by scanning transmission electron microscope. c Dispersion of Bio-Te in PmPV/toluene (upper) and in toluene only (bottom) with increasing stirring times on the X-axis, showing the preparation of Bio-Te-PmPV composites. PmPV is abbreviation of poly(m-phenylenevinylene)-co-2,5-dioctoxy-phenylenevinylene. d Transmission electron microscopy image of a Bio-Te crystalline nano-flake wrapped by PmPV layers. Inset is the image after fast Fourier transformation (FFT). e Raman spectra of Bio-Te, Bio-Te-PmPV, chemically synthesized tellurium nanocrystals (Chem-Te), Chem-Te-PmPV, and PmPV. f Left: the absorption spectrum of Bio-Te. This curve was obtained by subtracting the absorption of PmPV (0.5 g/L in toluene) from that of Bio-Te-PmPV. Right: photoluminescence (PL) spectra of Bio-Te-PmPV and pure PmPV. Inset: optical linear transmission and extinction coefficient as functions of Te concentrations at 532 nm. g The PL decay kinetics of PmPV and Bio-Te-PmPV at 528 nm excitation. The inset shows a blow up of the blue shaded region, showing the quenching effect caused by tellurium
