Modelling of polymer-carbon nanotube heterojunctions for photovoltaic applications

  1. GLANZMANN, LIVIA NOEMI
Supervised by:
  1. Angel Rubio Secades Director
  2. Duncan John Mowbray Director

Defence university: Universidad del País Vasco - Euskal Herriko Unibertsitatea

Fecha de defensa: 31 January 2017

Committee:
  1. Paola Ayala Chair
  2. Nerea Zabala Unzalu Secretary
  3. Larry Lüer Committee member
  4. Vito Despoja Committee member
Department:
  1. Polímeros y Materiales Avanzados: Física, Química y Teconología

Type: Thesis

Teseo: 121521 DIALNET lock_openADDI editor

Abstract

Semiconducting single-walled carbon nanotubes (s-SWNT) are promising materialsfor efficient organic photovoltaics (OPVs). Unfortunately, the implementation of s-SWNTs has so far not lead to the expected increase in power conversion efficienciesof OPVs. For this reason, we want to study the electronic processes within polymer-SWNT heterojunctions. Transient spectroscopy provides direct information aboutphotoexcitation processes in blends. We modelled the transient spectrum of apolymer:fullerene:s-SWNT blend using Linear Response. Based on our results, weare able to explain the structure transient spectra of s-SWNT systems and theelectronic dynamics linked to it. Further, we studied the internal quantum efficiencyof different donor/acceptor blends by carrying out calculations of the Landauer-Bütticker conductance of prototypical donor/acceptor heterojunctions. We find adependence of the conductivity on the level alignment. By improving the levelalignment of the polymer and SWNT through the use of larger band gap SWNTs,one may obtain a dramatic improvement in OPV efficiency. In summary, our resultsprovide a deeper insight into the photoexcitation and electronic processes ofpolymer-carbon nanotube heterojunctions and thus support the development of moreefficient polymer-SWNT OPVs.