Enhanced Performance of P3HT/TiO₂ Bilayer Heterojunction Photovoltaic Device Having Gold Nanoparticles in the Donor Layer

Abstract

The photovoltaic effects of blending gold nanoparticles (AuNPs) into the donor layer of a poly(3-hexylthiophene) (P3HT)/TiO2 bilayer heterojunction device have been studied. P3HT was synthesized via the modified Gragnard metathesis method and AuNPs with sizes ranging from 12 to 15 nm were formed via a reduction of HAuCl4. The blending of AuNPs into P3HT caused a lower photoluminescence (PL) intensities and a decreased energy level of the highest occupied molecular orbital (HOMO) than the pristine P3HT owing to the good electron-accepting nature of AuNPs. Upon the use of P3HT-AuNPs as the donor layer, the decreased HOMO(donor) resulted in an increased open circuit voltage (V(OC)) and thus enabled the fabricated (P3HT-AuNPs)/TiO2 bilayer heterojunction photovoltaic device to have an improved power conversion efficiency of solar energy. V(OC) as well as the overall power conversion efficiency increased with an increase in the AuNP content as a result of additional interfaces which facilitated the charge separation of excitons and percolation pathways which enhanced the electron transfer to the TiO2 acceptor. Furthermore, unannealed P3HT-AuNPs exhibited nanoholes and provided photovoltaic devices a power conversion efficiency nearly two time higher than annealed P3HT-AuNPs.

Functionalized polythiophene for corrosion inhibition and photovoltaic application

“…The head‐to‐tail (HT) and head‐to‐head (HH) configurations of repeat units in polymer chain can be estimated from characteristics α‐methylene protons labeled as “b” that are directly connected to the thiophene ring. The signals in the 1 H‐NMR at 2.55 and 2.80 ppm indicates to HH and HT dyads arrangement, respectively 44 . The percentage of dyads content are calculated from the relative ratio of the integral of above‐mentioned peaks and which are estimated to be 20% HH and 80% HT for P3HT and 42% HH and 58% HT for P3HT‐CN.…”

“…This is a strong evidence for efficient incorporation of cyano groups into the polymer chain. Henceforth, from the onset absorption wavelength () of the UV–Vis spectra of the P3HT and P3HT‐CN, the optical band gap (), are estimated using Tauc's plot (Figure 2(b)) as 1.95 and 1.86 eV, respectively, are tabulated in Table 2, and are calculated following the Equation (6) 44 …”

“…Solution of tetrabutyl ammonium perchlorate (TBAP) / acetonitrile (0.1 M) was prepared and then purged with nitrogen gas and was used as supporting electrolyte. Ferrocene was used as known standard internal reference to calculate energy of highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) levels including the ferrocene value of −4.4 eV of synthesized polymers by valence effective Hamiltonian technique as follows using Equation () and () 44 where, and are the onset oxidation potential and the onset reduction potential versus Ag/AgCl, respectively.…”

Gold nanoparticle immobilization on ZnO nanorods via bi-functional monolayers: A facile method to tune interface properties

“…One of the possible strategies involves covalent bonding of the organic molecules using different surface chemistries in order to ensure that the ZnO organic interface is conducive to promote charge transfer [8,9]. Such hybrid systems exhibit many characteristic properties which can be used in applications such as biological sensors, lightemitting diodes, and solar cell devices [10,11].…”