The XRD pattern of the CIS precursor buy APR-246 was investigated and the result is shown in Figure 2b. As shown in Figure 2b, the mainly HKI272 crystalline phase was CIS, and the almost undetectable secondary CuSe phase was observed. For the further application of the CIS powder in the printing method, the CIS should be ground into the nano-scale particles. Figure 2 CIGS precursors observed in (a) nano-scale (nm) and micro-scale (μm, in the upset) morphologies (b) XRD pattern. The XRD patterns of the CIS precursor were investigated under various grinding time and with and without 1 wt.% KD1, and the results are shown in Figure 3. As shown in Figure 3, only the diffraction peaks of the

CIS phase were observed in the ground powders. The 2θ values of the diffraction

peak for the CIS particle under differently treated process had no apparent shift. This result suggests that the crystalline phases of the CIS particle are not changed as the grinding process is used. For the ground CIS precursor without KD1 addition, the full width at half maximum (FWHM) value of the (112) peak was 0.37°, 0.37°, 0.38°, 0.38°, and 0.38° as grinding time was 1, 2, 3, and 4 h, respectively, as Figure 3a shows; as shown in Figure 3b for ground CIS precursor with KD1 addition, the FWHM value of the (112) peak was 0.38°, 0.43°, 0.47°, and 0.52°, as grinding MAPK inhibitor time was 1, 2, 3, and 4 h, respectively. The increase in the FWHM values of the (112) peak suggests that the particle sizes of the CIS powder decrease with increasing grinding time. However, the variations in the particle sizes of the ground CIS powders are dependent on the KD1 concentration and grinding time and Parvulin they are not easily calculated from the surface observation. In the past, the particle size can be estimated using the Scherrer’s formula [16]: (1) where λ

is the X-ray wavelength, B is the full width of height maximum of a diffraction peak, θ is the diffraction angle, and k is the Scherrer’s constant of the order unity for usual crystal. For CIS powder ground without KD1 addition it aggregated into micro-scale particles with the diameter in the range of 1.3 to 6 μm (not shown here). However, as the KD1 was added, the CIS powder was ground into nano-scale after 4 h, and it had the average particle sizes approximately 20 to 50 nm (also not shown here). Those results indicate that as KD1 is added as dispersant, the particle sizes of the CIS power are really decreased from micro-scale to nano-scale. Figure 3 XRD patterns of the CIS precursors grinding using a 2-mm ZrO 2 ball (a) without KD1 dispersant and (b) with KD1 dispersant. Figure 4 shows the surface morphology of the CIS absorber layers on the Mo/Glass substrates, RTA was carried out at different temperatures for 10 min in a selenization furnace and without extra Se addition.