Raman spectroscopic study of CdS, PVA composite films

Abstract

ABSTRACT:A new material, which can be used in solar energy utilization, is obtained here by adding different weights of poly(vinyl alcohol) (PVA) to the semiconducting material CdS. The effect of this addition was studied by using FT-Raman spectrometer (based on 1500 mW Nd : YAG laser at 1064 nm), UV-Vis-IR (190 -800 nm) spectrophotometer, and X-ray diffractometer. Our experimental results indicated the appearance of several new Raman bands, which have not existed in both CdS and PVA. Some of the bands which are already existing in the Raman spectra of PVA showed an unexpected systematic increase in their intensities after the addition of CdS to the matrix. On the other hand, some of the new Raman bands appeared in special concentrations of PVA only, whereas some of the Raman bands of CdS were found to disappear after adding PVA. Finally, shifts in some bands associated with random increase in their intensities after adding PVA to CdS was detected in the FT-Raman analysis. The experimental evidence given here might be attributed to the occurrence of new bonds, indicating that the produced mixture is a new material. The assignment of the new bands as well as an interpretation of the obtained variations is given here. Our X-ray diffraction data confirmed the interpretation introduced here. Moreover, the UV-Vis spectra confirmed the existence of new absorption bands in the Visible region. The I-V characteristic curve was measured for a selected concentration of the new composite material, showing a remarkable increase in the values of the conduction current of about two orders of magnitude as compared with the pure PVA material.

Spectroscopic analysis of CdCl2 doped PVA–PVP blend films

“…These peak assignments are listed in table 1. These peaks are attributed to different molecular vibrations, which are in agreement with similar assignments made by other researchers [33][34][35][36].…”

Enhancement of the optical properties of poly vinyl alcohol by doping with silver nanoparticles

“…Poly vinyl alcohol (PVA) has been used in many applications since its discovery in 1924 1–3. The optical applications of PVA are based on polarization and filtration of light and photograph 4.…”

Fabrication of poly(vinyl alcohol)‐graphene quantum dots coated with poly(3,4‐ethylenedioxythiophene) for supercapacitor

“…Figure (b) shows a spectrum of PVA nanofiber with three different modes of vibrations contributed by (CH 2 CHOH). A band at 1156 cm −1 is attributed to OH and other peaks at 1448 and 2918 cm −1 are ascribed to the stretching mode of CH and CH 2 , respectively . For GQDs, three characteristic peaks appeared at 1549 and 1390 cm −1 are correspond to the G‐band and D‐band followed by the most intense peak observed at 2925 cm −1 , which is associated with 2D‐band .…”

“…A band at 1156 cm 21 is attributed to OH and other peaks at 1448 and 2918 cm 21 are ascribed to the stretching mode of CH and CH 2 , respectively. 35 For GQDs, three characteristic peaks appeared at 1549 and 1390 cm 21 are correspond to the G-band and Dband 36 followed by the most intense peak observed at 2925 cm 21 , which is associated with 2D-band. 37 The D-band represents a disorder feature of the materials, which associated with the conversion of sp 2 to sp 3 due to the presence of some defects, that is, edges, functional groups or structural disorders and the G-band is associated with the vibration of the sp 2 hybridized carbon.…”