TY - JOUR

T1 - Effect of Thermal Annealing on Structure and Optical Properties of Poly(p-xylylene)-PbS Thin Films

AU - Nesmelov, A. A.

AU - Oveshnikov, L. N.

AU - Ozerin, S. A.

AU - Zav'Yalov, S. A.

AU - Zubavichus, Ya V.

AU - Orekhov, A. S.

AU - Streltsov, D. R.

AU - Kiryukhin, Yu I.

AU - Chvalun, S. N.

PY - 2019/4/25

Y1 - 2019/4/25

N2 - In this study, wide-angle X-ray diffraction, X-ray absorption spectroscopy, and transmission electron microscopy were employed to address the crystalline structure and morphology of poly(p-xylylene)-PbS nanocomposite thin films prepared by vapor deposition polymerization as well as their evolution upon thermal annealing. It was found that as-synthesized samples with different PbS contents demonstrate similar diffraction patterns that cannot be fully ascribed to a decrease in crystallite size, indicating distorted crystal structure of PbS nanoparticles compared to the bulk PbS. X-ray absorption spectroscopy reveals wide distribution of Pb-S bond lengths with a minimum value of 2.67 Å, which can be attributed to the presence of molecular (PbS)n clusters in the studied films. It was shown that thermal annealing can be used to control the size of PbS nanoparticles and, as a consequence, optical properties of the composite films. The UV-vis absorption spectra demonstrate pronounced red shift of the absorption edge correlated with the growth of PbS nanoparticles upon annealing. Comprehensive analysis of several theoretical models describing the effect of nanoparticles size on optical band gap of the composite material has been performed and compared with the experimental data.

AB - In this study, wide-angle X-ray diffraction, X-ray absorption spectroscopy, and transmission electron microscopy were employed to address the crystalline structure and morphology of poly(p-xylylene)-PbS nanocomposite thin films prepared by vapor deposition polymerization as well as their evolution upon thermal annealing. It was found that as-synthesized samples with different PbS contents demonstrate similar diffraction patterns that cannot be fully ascribed to a decrease in crystallite size, indicating distorted crystal structure of PbS nanoparticles compared to the bulk PbS. X-ray absorption spectroscopy reveals wide distribution of Pb-S bond lengths with a minimum value of 2.67 Å, which can be attributed to the presence of molecular (PbS)n clusters in the studied films. It was shown that thermal annealing can be used to control the size of PbS nanoparticles and, as a consequence, optical properties of the composite films. The UV-vis absorption spectra demonstrate pronounced red shift of the absorption edge correlated with the growth of PbS nanoparticles upon annealing. Comprehensive analysis of several theoretical models describing the effect of nanoparticles size on optical band gap of the composite material has been performed and compared with the experimental data.

KW - X-RAY-DIFFRACTION

KW - LEAD SULFIDE

KW - ELECTRONIC-PROPERTIES

KW - ELECTRICAL-PROPERTIES

KW - PRESSURE-DEPENDENCE

KW - SIZE-DEPENDENCE

KW - QUANTUM DOTS

KW - BAND-GAP

KW - PBS

KW - STRAIN

UR - http://www.scopus.com/inward/record.url?scp=85065289088&partnerID=8YFLogxK

U2 - 10.1021/acs.jpcc.8b12046

DO - 10.1021/acs.jpcc.8b12046

M3 - Article

AN - SCOPUS:85065289088

VL - 123

SP - 10517

EP - 10528

JO - Journal of Physical Chemistry C

JF - Journal of Physical Chemistry C

SN - 1932-7447

IS - 16

ER -