skip to main content

Title: Cross Kelvin force microscopy and conductive atomic force microscopy studies of organic bulk heterojunction blends for local morphology and electrical behavior analysis

Bulk Heterojunction (BHJ) organic photovoltaic devices performances depend on the relative organization and physical properties of the electron-donor and -acceptor materials. In this paper, BHJs of poly(3-hexyl-thiophene) (P3HT) associated with an electron acceptor material, 1-(3-methoxycarbonyl)-propyl-1-phenyl[6,6]C6 (PCBM) or [Ni(4dodpedt){sub 2}], are studied in terms of morphology, ordering, and electrical properties. First, comparison between the two BHJs performed by Atomic Force Microscopy (AFM) and Raman characterizations shows that P3HT structuration is improved by blending with [Ni(4dodpedt){sub 2}]. Then, the relationship between charges trapping, electrical properties, and film morphology is investigated using conductive AFM and Kelvin Force Microscopy. Measurements in dark condition and under solar cell simulator provide complementary information on electrical phenomena in these organic nanostructures. Finally, time dependent measurement highlights the influence of charges stacking on conduction. Specifically, we demonstrate that charge accumulation initiated by illumination remains valid after switching off the light, and induces the modification in current versus voltage characteristic of P3HT: PCBM blend. Finally, we observe a current increasing which can be attributed to the energy barrier decreasing due to charges trapping in PCBM.
Authors:
 [1] ;  [2] ;  [1] ;  [2] ;  [2] ; ;  [3] ;  [2] ; ;  [3] ;  [2]
  1. LAPLACE, Université Paul Sabatier, 118 Route de Narbonne, 31062 Toulouse (France)
  2. (France)
  3. UPS, INPT, Université de Toulouse, LCC 31077 Toulouse (France)
Publication Date:
OSTI Identifier:
22413069
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 117; Journal Issue: 5; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; ATOMIC FORCE MICROSCOPY; BINDING ENERGY; COMPARATIVE EVALUATIONS; ELECTRIC CONDUCTIVITY; ELECTRONS; FILMS; HETEROJUNCTIONS; ILLUMINANCE; MORPHOLOGY; NANOSTRUCTURES; PHOTOVOLTAIC EFFECT; POLYCYCLIC SULFUR HETEROCYCLES; SOLAR CELLS; THIOPHENE; TIME DEPENDENCE; TRAPPING; VALENCE