Investigation of the solvent influence on polymer–fullerene solar cells by low frequency noise spectroscopy

Abstract

The electron density of states and recombination kinetics of bulk heterojunction solar cells have been determined by means of low-frequency noise spectroscopy at room temperature and in dark conditions. The observed differences in the disorder parameter and electron lifetime are attributed to a different film ordering of the active layer because of the influence of a solvent additive. Blends prepared with the reference solvent resulted in the lowest electron lifetime and density of states population, while blends prepared with the addition of a high boiling point solvent resulted in a more efficient charge carrier separation and a higher electron lifetime

Probing Temperature-Dependent Recombination Kinetics in Polymer:Fullerene Solar Cells by Electric Noise Spectroscopy

“…This is consistent with the observed increased mesoscopic ordering in the blend. As already reported in literature, the blend casted from a high-boiling-point solvent, as the oDCB+THN, has a higher polymer crystallinity in the active layer as compared to the blend prepared with a low-boiling-point solvent, as the oDCB [8,48]. Indeed, the increase of the film ordering induces a vertical phase separation between polymer and fullerene materials which causes a diffusion out of the PCBM material within the blend [49].…”

Effects of plasmon resonance on the low frequency noise and optoelectronic properties of Au/Cu codoped ZnO based photodetectors

“…The photodetector performance can be evaluated using the normalized photocurrent to the dark current ratio (NPDR), which proves direct information about the noise equivalent power and photoresponsivity resulting from the dark current. The NPDR is expressed as the following equation [13]:…”

“…However, doped ZnO based photodetectors suffer from low photoresponse mainly associated with the low optical absorbance and higher noise current. To overcome the above mentioned issues, noble metal nanoparticles can also be decorated with ZnO nanoparticles, which enhances the properties due to their localized surface plasmon resonance (LSPR) property such as transfer of plasmon resonance energy from plasmonic metal NPs to nanostructures, near-eld enhancement, and large absorption of incident light [13]. The advantages of using Au Nps to enhance the optical properties have been con rmed [14]; however, their optimization in reducing noise current is lacking in the literature.…”

Hole‐mobility limits for the Zn(OC)2 organic semiconductor obtained by SCLC and field‐effect measurements

“…In disordered organic materials, the charge transport depends on the pathways that are available for carriers to organize a macroscopic electric current . For example, in the case of conjugated polymers, the transport is favored in the conjugated direction and the effect of the deposition conditions (e.g., temperature and solvent type) modifies the film‐ordering and hence the charge carrier transport . For poly(3‐hexyl)thiophene, for example, the highest reported hole mobility has a value of 0.1 cm 2 V −1 s −1 in the backbone direction , whereas it is much lower in the π‐stacking direction, with typical values in the range between 0.02 and 0.06 cm 2 V −1 s −1 (conduction by hopping) , and almost negligible conduction along the alkyl side chain .…”