The Cu2S nanoprisms were characterized by high-resolution
transmission electron microscopy (HRTEM), X-ray diffraction
(XRD), UV-vis absorbance (UV-vis) as shown in Fig. 3. From
the HRTEM shown (Fig. 3A), taken from a top face of the
nanoprism, we see that the Cu2S nanoprisms have a high degree
of crystallinity. The X-ray diffraction pattern for the cuprous
sulfide hexagonal nanoprisms is shown in Fig. 3B. The XRD
results indicate high phase-purity of the samples. All peaks
present may be indexed to the low-temperature stable monoclinic
crystal phase of Cu2S (low-chalcocite, JCPDS 01-083-1462).
Recent work from Korgel and coworkers16 as well as Alivisatos
and coworkers17 report the synthesis of Cu2S in the hightemperature
stable hexagonal crystal phase. Other crystal phases
of copper sulfide nanocrystals may also be produced through
similar thermal decomposition techniques.18