Investigation on the effects of graphene in P3HT as an active layer in solar cells / Fadilah Abd Wahab

• Main Author: Fadilah , Abd Wahab
• Format: Thesis
• Published: 2019
• Subjects: Q Science (General); QC Physics
• Online Access: http://studentsrepo.um.edu.my/11949/2/Fadzilah.pdf; http://studentsrepo.um.edu.my/11949/1/Fadilah.pdf; http://studentsrepo.um.edu.my/11949/
• Institution: Universiti Malaya

Presently, fullerenes have been the acceptor materials of the most intensively studied bulk heterojunction (BHJ) structure of Polymer Solar Cell (PSC). However fullerene and its derivatives have several disadvantages including high cost, poor morphological stability and limited absorption of light. The main aim of this study is to investigate the effects of graphene as an acceptor in PSC. Graphene is synthesized in this study using two methods; the first is the exfoliation process of graphite flakes into graphene sheets (GS) and secondly is the oxidation process of graphite flakes using Hummer’s Method to form graphene oxide (GO). The experimental results of the synthesized GS are presented on the optical, structural, and morphological properties. Spin-coating method is utilized to form the blend thin films either on the glass or indium tin oxide (ITO) electrode. Doping of 2.5% GS obtained from exfoliation process into Poly(3-hexylthiophene) (P3HT), induces energy transfer at the P3HT:GS interface as indicated by the photoluminescence (PL) quenching in the blend film. Then, the blend film of P3HT:GS is deposited onto ITO electrode which covered with a thin layer of semi-transparent conducting polymer/poly(ethylene dioxythiophene):polystyrenesulfonic acid (PEDOT:PSS), to form ITO/PEDOT:PSS/P3HT:GS/Aluminium(Al) PSC device. In this study, the PSC efficiency has increased from 6.32 x 10-4% to 1.01 x 10-3%, for device without and with GS, respectively. In the second method of synthesis of this study, GO is successfully produced from Hummer’s Method, as evident from the optical, structural, and morphological characterizations. Nevertheless the films consist of P3HT blended with GO do not show a PL quenching, indicating of no energy transfer at the P3HT:GO interface. This PL result shows that the synthesized GO produced from Hummer’s method is non-effective acceptor material to be used as an active layer in PSC application.