On the Donor: Acceptor Features for Poly(3-hexylthiophene): TiO2 Quantum Dots Hybrid Materials Obtained via Water Vapor Flow Assisted Sol-Gel Growth

Here, we present a novel methodology for the preparation of P3HT:TiO2 quantum dots hybrid materials via water vapor flow-assisted sol-gel growth focusing on the structural, optical and electrical property characterization complemented with first-principles calculations as a promising donor-acceptor system for polymer and hybrid solar cells. X-ray diffraction and UV-Vis spectroscopy analyses suggest that the increasing concentration of TiO2 quantum dots leads to the formation of higher amounts of amorphous regions while the crystalline regions exhibited interesting aspect ratio modifications for the P3HT polymer. Raman spectra evidenced the formation of charge carriers in the P3HT with increasing TiO2 quantum dots content and the P3HT:TiO2 50:50 weight ratio resulted in the best composition for optimizing the bulk electronic conductivity, as evidenced by impedance spectroscopy studies. Our DFT calculations performed for a simplified model of the P3HT:TiO2 interface revealed that there is an important contribution of the thiophene carbon atoms states in the conduction band at the Fermi level. Finally, our DFT calculations also reveal an evident gain of electron density at the TiO2 (101) surface while the thiophene rings showed a loss of the electron density, thus confirming that the P3HT:TiO2 junction acts as a good donor-acceptor system. In our opinion, these results not only present a novel methodology for the preparation of P3HT:TiO2 quantum dots hybrid materials but also reveal some key aspects to guide the more rational design of polymer and hybrid solar cells.

Automated summary

In this study, a new method for the preparation of P3HT:TiO2 quantum dot hybrid materials was proposed through water vapor flow-assisted sol-gel growth. The structural, optical, and electrical properties were characterized, and first-principles calculations were performed to evaluate their potential as donor-acceptor systems for polymer and hybrid solar cells. The results showed that the concentration of TiO2 quantum dots affected the formation of amorphous regions and aspect ratio modifications of the P3HT polymer. Raman spectra confirmed the formation of charge carriers in P3HT, and impedance spectroscopy studies indicated that the best composition for optimizing bulk electronic conductivity was P3HT:TiO2 with a 50:50 weight ratio. Our DFT calculations revealed important contributions of thiophene carbon atoms states in the conduction band at the Fermi level and demonstrated that the P3HT:TiO2 junction acted as a good donor-acceptor system. These findings not only provide a novel methodology for preparing P3HT:TiO2 quantum dot hybrid materials, but also offer insights for the rational design of polymer and hybrid solar cells.