ordinary PS, the PL intensity of the as-prepared PS increases during the first four
months and then saturates when exposed to ambient air. No PL degradation was
observed for eight months, and the peak position remained unchanged. This PL
stability is attributed to the formation of stable FeaSi bonds on the surface of
the PS.
The hydrothermal method has been used to prepare monodispersed ZnS (6 nm)
[10] and CdS nanocrystals (16 nm) [11]. By hydrothermal polymerization and
simultaneous sulfidation processes, nanocomposites CdS/poly(vinyl acetate) nanorods [12] and nanospheres [13] were synthesized. In aqueous hydrazine solutions, nonstoichiometric metal telluride nanocrystallites such as Cu 2:86 Te 2 , Cu 7 Te 5 ,
Cu 2Àx Te, and Ag 7 Te 4 [14], and cubic Co 9 S 8 were hydrothermally synthesized [15].
Other transition metal chalcogenides, such as single-molecular-layer MoS 2 [16]
and MoSe 2 [17] were also prepared under hydrothermal conditions.
As shown in Figure 7.3, novel millimeter-sized tubular crystals of Ag 2 Se were
grown via a hydrothermal reaction route from AgCl, Se and NaOH at 155
C [18].
Similarly, CuS millimeter-scale tubular crystals were synthesized at 185
C [19].
Reacting Bi 2 Te 3 with I 2 via an iodine transport hydrothermal method at temperatures ranging from 190–200
C resulted in BiTeI submicrometer hollow spheres
with diameters of 200–300 nm [20]. The sphere wall is composed of BiTeI nanoparticles with average diameter 5 nm and thickness about 10 nm. The transmission electron microscope (TEM) and high-resolution transmission electron microscope (HRTEM) images of BiTeI spheres are shown in Figure 7.4. SbSI rodlike
crystals [21] and nanorods [22] with diameters of 20–50 nm and lengths up to
several micrometers were synthesized at about 200
C.
Fig. 7.2. Time evolution of the PS spectra of the Fe-passivated
PS (A) and an ordinary PS (B) exposed to ambient air at room
temperature for (A) (a) 2 h, (b) 45 days, (c) 75 days, (d) 110
days, (e) 140 days, (f ) 170 days, (g) 235 days, (h) 500 days; (B)
(a) 0 days, (b) 17 days, (c) 39 days, (d) 50 days, (e) 65 days.
7 Solvothermal Synthesis of Non-Oxide Nanomaterials
172
months and then saturates when exposed to ambient air. No PL degradation was
observed for eight months, and the peak position remained unchanged. This PL
stability is attributed to the formation of stable FeaSi bonds on the surface of
the PS.
The hydrothermal method has been used to prepare monodispersed ZnS (6 nm)
[10] and CdS nanocrystals (16 nm) [11]. By hydrothermal polymerization and
simultaneous sulfidation processes, nanocomposites CdS/poly(vinyl acetate) nanorods [12] and nanospheres [13] were synthesized. In aqueous hydrazine solutions, nonstoichiometric metal telluride nanocrystallites such as Cu 2:86 Te 2 , Cu 7 Te 5 ,
Cu 2Àx Te, and Ag 7 Te 4 [14], and cubic Co 9 S 8 were hydrothermally synthesized [15].
Other transition metal chalcogenides, such as single-molecular-layer MoS 2 [16]
and MoSe 2 [17] were also prepared under hydrothermal conditions.
As shown in Figure 7.3, novel millimeter-sized tubular crystals of Ag 2 Se were
grown via a hydrothermal reaction route from AgCl, Se and NaOH at 155
C [18].
Similarly, CuS millimeter-scale tubular crystals were synthesized at 185
C [19].
Reacting Bi 2 Te 3 with I 2 via an iodine transport hydrothermal method at temperatures ranging from 190–200
C resulted in BiTeI submicrometer hollow spheres
with diameters of 200–300 nm [20]. The sphere wall is composed of BiTeI nanoparticles with average diameter 5 nm and thickness about 10 nm. The transmission electron microscope (TEM) and high-resolution transmission electron microscope (HRTEM) images of BiTeI spheres are shown in Figure 7.4. SbSI rodlike
crystals [21] and nanorods [22] with diameters of 20–50 nm and lengths up to
several micrometers were synthesized at about 200
C.
Fig. 7.2. Time evolution of the PS spectra of the Fe-passivated
PS (A) and an ordinary PS (B) exposed to ambient air at room
temperature for (A) (a) 2 h, (b) 45 days, (c) 75 days, (d) 110
days, (e) 140 days, (f ) 170 days, (g) 235 days, (h) 500 days; (B)
(a) 0 days, (b) 17 days, (c) 39 days, (d) 50 days, (e) 65 days.
7 Solvothermal Synthesis of Non-Oxide Nanomaterials
172