TY - JOUR
T1 - Microwave Synthesis of Silver Sulfide and Silver Nanoparticles: Light and Time Influence
AU - Magalhães Sousa, David
AU - Chiappim, William
AU - P. Leitão, Joaquim
AU - Lima, João Carlos
AU - Ferreira, Isabel
N1 - info:eu-repo/grantAgreement/EC/H2020/647596/EU#
info:eu-repo/grantAgreement/EC/H2020/645241/EU#
info:eu-repo/grantAgreement/FCT/5876/147333/PT#
UIDB/50025/2020
UIDP/50025/2020
UID/CTM/50025/2019
.
PY - 2020/6/9
Y1 - 2020/6/9
N2 - Silver sulfide (Ag2S) is a low band gap material, which absorbs near-infrared light and is of great importance in areas such as nanotechnology and biomedicine. We report the influence of the starting reagents, synthesis time, and light radiation on the geometry and size of silver sulfide nanoparticles and on the fraction of metallic Ag obtained in a microwave reactor. The X-ray diffraction diffractograms confirmed that Ag2S is the main product if the reaction's precursor contains silver in the oxidation state of +1 and mostly metallic silver (Ag°) when it is +2. Small nanoparticles (∼6 nm) of spherical geometry are present in the transmission electron microscopy images for the synthesis performed with the lamp light ON, while with the light switched OFF, wider and hundreds of nanometers longer particles are observed. This discriminative effect occurs with shorter synthesis time duration (<10 min) but when the time of reaction is extended, the particles coalesce for both light and dark conditions. Overall, it was observed by photoluminescence that crystalline Ag and Ag2S 4-8 nm nanoparticles obtained in 15 min and light irradiation during synthesis have a clear relative increase of the radiative recombination channels of the charged carriers, which are typical of materials characterized by the involvement of low density of states inside the band gap.
AB - Silver sulfide (Ag2S) is a low band gap material, which absorbs near-infrared light and is of great importance in areas such as nanotechnology and biomedicine. We report the influence of the starting reagents, synthesis time, and light radiation on the geometry and size of silver sulfide nanoparticles and on the fraction of metallic Ag obtained in a microwave reactor. The X-ray diffraction diffractograms confirmed that Ag2S is the main product if the reaction's precursor contains silver in the oxidation state of +1 and mostly metallic silver (Ag°) when it is +2. Small nanoparticles (∼6 nm) of spherical geometry are present in the transmission electron microscopy images for the synthesis performed with the lamp light ON, while with the light switched OFF, wider and hundreds of nanometers longer particles are observed. This discriminative effect occurs with shorter synthesis time duration (<10 min) but when the time of reaction is extended, the particles coalesce for both light and dark conditions. Overall, it was observed by photoluminescence that crystalline Ag and Ag2S 4-8 nm nanoparticles obtained in 15 min and light irradiation during synthesis have a clear relative increase of the radiative recombination channels of the charged carriers, which are typical of materials characterized by the involvement of low density of states inside the band gap.
UR - http://www.scopus.com/inward/record.url?scp=85087917098&partnerID=8YFLogxK
U2 - 10.1021/acsomega.0c00656
DO - 10.1021/acsomega.0c00656
M3 - Article
C2 - 32548471
AN - SCOPUS:85087917098
SN - 2470-1343
VL - 5
SP - 12877
EP - 12881
JO - ACS Omega
JF - ACS Omega
IS - 22
ER -