Polymer-Nanoparticle Hybrid Photovoltaic Research for U.S. Air Force Applications
Abstract
The polymer photovoltaic devices based on the poly(3-hexylthiophene)/TiO2 nanorods hybrid material (P3HT/TiO2) has better thermal stability than that of P3HT/PCBM hybrid material. We have investigated the effect of polymer molecular weight on the morphology and performance of P3HT/TiO2 nanorod hybrid photovoltaic devices by using scanning near field optical microscopy (SNOM), atomic force microscopy (AFM) and confocal Raman microscopy. The results provide a direct observation of the correlation between the nanoscale absorption, morphology and device performance. An enhancement in the device performance can be achieved by removing or replacing the insulating surfactant on the TiO2 nanorods surface with a more conductive ligand, which can play the role to assist charge separation efficiency or also to prevent from back recombination, giving a large improvement in the short circuit current and fill factor. The F-doped TiO2 nanocrystal has increased the carrier concentration, conductivity and charge separation efficiency of the hybrid that results improved power conversion efficiency. A novel series of soluble alternating conjugated copolymers, comprised of 9,9-dihexylfluorene and cyclopentadithiophenes (P1-P5), were synthesized via Pd-catalyzed Suzuki coupling reaction in good yields. The P2 and P3 with electron donating non-pi-substituents (ethylenedioxy and propylenedioxy bridges the 3,3 positions of the thiophene groups) display high fluorescence quantum yields and red-shifted absorption as compared with non substituted P1. However, the P4 and P5 are weakly fluorescent and exhibit blue-shifted absorption which are due to the presence of electron-withdrawing pi-substituents (carbonyl and dicyanoethenyl). Their applications in the photovoltaic device are current under investigation.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jan 06, 2010
- Accession Number
- ADA512578
Entities
People
- Chun-Wei Chen
- Wei-fang Su
Organizations
- National Taiwan University