Eco-friendly fabrication of organic solar cells: electrostatic stabilization of surfactant-free organic nanoparticle dispersions by illumination

Abstract

Earlier reports have discussed the manifold opportunities that arise from the use of eco-friendly organic semiconductor dispersions as inks for printed electronics and, in particular, organic photovoltaics. To date, poly(3-hexylthiophene)...

Organic Solar Cells: Electrostatic Stabilization of Organic Semiconductor Nanoparticle Dispersions by Electrical Doping

“…[ 9,10 ] Recent reports indicated that the inclusions of fullerenes with residual solubility in the dispersion medium help the dispersion stability by displacing the negative countercharges from the positively charged nanoparticles. [ 24,57 ] Earlier investigations on solution‐processed polymer:fullerene light‐harvesting layers demonstrated no detrimental effects of small amounts of F 4 TCNQ on the OSC performance. [ 28,32,37,42 ]…”

“…[9,10] Recent reports indicated that the inclusions of fullerenes with residual solubility in the dispersion medium help the dispersion stability by displacing the negative countercharges from the positively charged nanoparticles. [24,57] Earlier investigations on solution-processed polymer:fullerene light-harvesting layers demonstrated no detrimental effects of small amounts of F 4 TCNQ on the OSC performance. [28,32,37,42] We prepared solutions of P3HT:ICBA (1:1 w/w) in chloroform (8 g L −1 ) and added different amounts of F 4 TCNQ (w F TCNQ 4 between 0.1 and 1 wt% with respect to the mass of P3HT) to the solutions by injecting the respective amount of F 4 TCNQ/ acetonitrile solution (10 g L −1 ).…”

“…[ 23 ] And recently, we reported that the intrinsic stability of P3HT and P3HT:ICBA nanoparticle dispersions is also of electrostatic origin. [ 24 ] If electrostatic effects are powerful enough to stabilize P3HT:ICBA nanoparticles over an extended period of time, the deliberate generation of (surface) charges on the nanoparticles should enhance the colloidal stability. A common approach to charge organic semiconductors is electrical p‐doping with strong oxidizing agents such as 2,3,5,6‐tetrafluoro‐7,7,8,8‐tetracyanoquinodimethane (F 4 TCNQ).…”

Microfluidics: Continuous‐Flow Synthesis of Nanoparticle Dispersions for the Fabrication of Organic Solar Cells

“…According to our recent experimental observations, photoexcitation of the organic semiconductors during nanoprecipitation increases the electrostatic stability of the nanoparticle dispersions. [ 11 ] In a nutshell, photoexcitation of P3HT during precipitation leads to positive charging of the nanoparticles which promotes electrostatic stabilization of the dispersion. In the blend, the residual solubility of ICBA in ethanol supports the displacement of the negative countercharges from the nanoparticles.…”

“…[ 9,10 ] Recently, we revealed that electrostatic repulsion of the BHJ nanoparticles promotes the stability of surfactant‐free dispersions and that irradiation during nanoprecipitation can enhance the charging of nanoparticles. [ 11 ]…”