Excitation spectra are (a) and (b), which were measured at 395 and 465 nm, respectively. Emission

spectra are (c) and (d), which were excited at 350 and 310 nm, respectively. To investigate the photoluminescence efficiency of the BSB-Me nanocrystal water dispersion, we estimated its photoluminescence quantum yield. The manner to estimate the quantum yield of a fluorophore is by comparison with standards of known quantum yield. We used the standard of BSB-Me dichloromethane solution referred in the literature [6], in which the BSB-Me dichloromethane solution had an absolute photoluminescence quantum yield of 95 ± 1%. The quantum yields of the standards are mostly independent of excitation wavelength, so the standards can be used wherever they display useful absorption [32, 33]. Determination of the quantum yield is generally accomplished by comparison of the wavelength integrated intensity #selleck products randurls[1|1|,|CHEM1|]# of the unknown to that of the standard. The optical density is kept below 0.05 to avoid inner filter effects, or the optical densities of the sample and reference (r) are matched at the excitation wavelength. The quantum yield of the unknown is calculated using Equation 1: (1) where Q is the quantum yield, I is the integrated intensity (areas) of spectra, OD is the optical density, and n is the refractive index. The subscripted R refers to the reference fluorophore of

known quantum yield. The data of I and OD were obtained from Figure 7. The quantum yield of this website the BSB-Me nanocrystal water dispersion, which was calculated using Equation 1, was estimated to be 9.2 ± 0.1% (Table 1). Figure 7 Emission and absorption spectra of BSB-Me dichloromethane solution and BSB-Me nanocrystal water dispersion. Emission spectra of BSB-Me dichloromethane solution (a) and BSB-Me nanocrystal water dispersion (b). The excitation wavelength was 324 nm for each spectrum.

The integrated intensity (areas) of the spectra was calculated as 528,826 for (a) and 58,884 for (b). Inset: the absorption spectra of the BSB-Me dichloromethane solution (c) and BSB-Me nanocrystal water dispersion (d), where both samples had the same optical density of 0.045 at 324-nm wavelength. Table 1 Quantum yield, integrated intensity, optical density, and Linifanib (ABT-869) refractive index of the BSB-Me   Quantum yield (Q), % Integrated intensity (I )b Optical density (OD ) at λ = 324 nmc Refractive index (n ) at 20°C BSB-Me dissolved in dichloromethane (1 μM) 95 ± 1a 528,826 0.045 1.42 BSB-Me nanocrystal water dispersion (2 μM) 9.2 ± 0.1 58,884 0.045 1.33 aThe data was obtained from Table one of reference [6]. bThe data was obtained from Figure 7 (a and b). cThe data was obtained from Figure 7 inset (c and d). The crystallinity of the BSB-Me nanocrystals was confirmed using powder X-ray diffraction analysis (Figure 8). Two strong peaks were observed at 2θ = 9.0 and 13.6, corresponding with those previously reported for single bulk crystals [6].