Synthesis, Properties, and Solar-Cell Applications of Pentiptycene Incorporated Poly(p-phenylene vinylene)s
Date Issued
2010
Date
2010
Author(s)
Yang, Ming-Che
Abstract
In this thesis, we report the synthesis and electronic properties of pentiptycene-incorporated poly(phenylene vinylene)s (PPVs). We have also investigated the performance of these PPV-type derivatives as active materials for bulk heterojunction (BHJ) solar cells.
Our lab has been devoted to the synthesis of new pentiptycene building blocks, including dibromopentiptycene. We previously used dibromopentiptycene to synthesize pentiptycene-incorporated poly(phenylene vinylene)s by Heck coupling reactions, but the overall yield and polydispersity are poor. As a result, we turn to the more reactive diiodopentiptycene and the alterative building block divinylpentiptycene. We used pentiptycene quinone as the starting material and successfully obtained diiodopentiptycene and divinylpentiptycene through multistep synthesis, and particularly the SNAr reaction of a pentiptycene triflate. Two pentiptycene incorporated PPVs PEN-ROPPV and PEN-3ROPPV have been successfully prepared. These two polymers are blue-shifted in absorption and fluorescence spectra as compared to alkyl or alkoxy-substituted PPVs. The spectra of PEN-3ROPPV are somewhat red-shifted than those of PEN-ROPPV due to its lower fraction of the pentiptycene group. Their spectra in thin film are similar to those in dilute solutions, indicating negligible aggregation of polymers backbone.The cyclic voltammetric anodic curves of these two polymers are irreversible. The energy levels of their HOMOs and LUMOs are suitable for application in BHJ solar cells with PCBM as the electron acceptor. However, the power conversion efficiency are low partly owing to poor light harvesting of the sun light. Another possible factor that is responsible to the low efficiency of solar cells is the morphology even though we had expected that pentiptycene could interact well with PCBM.
Subjects
Pentiptycene
Poly(p-phenylene vinylene)s
Solar Cells
Type
thesis
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