The Potential of P3HT:3C-SiC Composite Structures for Hybrid Photovoltaics

Abstract

In hybrid solar cells, a nanoscale donor/acceptor junction between an organic and an inorganic semiconductor material is mostly established by mixing the organic semiconductor with inorganic nanocrystals or by infiltration into an inorganic nanostructure scaffold. In this report, we describe the characteristics of submicron-sized cubic silicon carbide and its potential as acceptor material in hybrid photovoltaics. The SiC nanocrystals are derived from a sol-gel based precursor after carbothermal reduction. The process allows reasonable control of nanostructure size and optoelectronic properties can be altered by SiC doping via sol-gel processing additives. SiC has widely been neglected from this application in the past, because of its indirect band gap and high fabrication costs. Still, its band energies are suitable to match the HOMO/LUMO of common organic donors, providing a promising outlook for its acceptor functionality in hybrid photovoltaics. This is shown by fast-laser spectroscopy on according P3HT:SiC hybrid layers, which shows indication for potential long-lived P3HT polaron emission.Peer reviewe

Spray-coating deposition techniques for polymeric semiconductor blends

“…The pristine F8TBT and P3HT films, as deposited by spray-coating show efficient photo-luminescence (PL) under blue/UV laser excitation; with values in the ranges of 10% and 4-5% respectively, in consistency with the literature [16,24]. The as deposited 1:1 blends show a significantly reduced PL emission (Figure 4), as charge-separation at heterojunction interfaces now competes with radiative recombination (PL quenching); the degree of such quenching is also therefore an indicator of likely photovoltaic cell performance [22].…”

Characterization of Surface and Structure of In Situ Doped Sol‐Gel‐Derived Silicon Carbide

“…In particular from hybrid solar cells, it is a well‐known fact that the surface properties of the inorganic component substantially determine the efficiency of the device, for example, via surface trap states fostering trap‐mediated recombination or inter‐particle charge transport limitations, caused by their stabilizing ligands . In the case of silicon carbide nanoparticles within a conjugated polymer matrix, Kettner et al have observed extended emission lifetimes, assigned to the formation of longer lived polarons upon photoinduced electron transfer to the inorganic acceptor or surface trap states, which have been suggested in either case to be beneficial for their function in hybrid photovoltaics . However, also here the surface is the most crucial point, when incorporating SiC nanoparticles into the organic semiconductor matrix of a hybrid solar cell.…”

“…[16,19] This motivates a broadening of SiC's application range towards new fields, such as the electronic acceptor in organic/inorganic hybrid photovoltaics, as robust photoelectrode in catalysis and for nanostructured blue light emitters, where nanoscale or large surface area is required. [20][21] In particular from hybrid solar cells, it is a well-known fact that the surface properties of the inorganic component substantially determine the efficiency of the device, e.g. via surface trap states fostering trap-mediated recombination or inter-particle charge transport limitations, caused by their stabilizing ligands.…”