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Title: Investigating charge generation in polymer:non-fullerene acceptor bulk heterojunction films

Journal Article · · Organic Electronics
 [1];  [2];  [1];  [1];  [1];  [1];  [1];  [1];  [2]
  1. Univ. of Queensland, St. Lucia (Australia)
  2. National Renewable Energy Lab. (NREL), Golden, CO (United States)
+ Show Author Affiliations

Non-fullerene acceptors are now capable of being used in high efficiency bulk heterojunction (BHJ) donor-acceptor organic solar cells. Acceptors comprising single or multiple linked chromophores have been used. We have developed a new non-fullerene molecular acceptor as well as two non-polymeric macromolecular materials that contain four equivalents of a similar chromophore, but can adopt different spatial arrangements of the chromophores. We compare the effect of having single and multiple chromophores within a macromolecule on the charge generation processes in P3HT:non-fullerene acceptor BHJ films using Transient Absorption Spectroscopy (TAS) and Time Resolved Microwave Conductivity (TRMC) measurements. It was found from the TAS measurements that at low weight percent (5 wt%) the single chromophore formed more polarons than the acceptors in which chromophores were linked, due to it having a more even distribution within the film. At higher concentrations (50 wt%) the trend was reversed due to the single chromophore forming crystalline domains, which reduced the interface area with the P3HT donor. The TRMC measurements showed that more mobile carriers were formed in the macromolecular acceptors when used at low concentrations in the blend and, independent of concentration, mobile carriers had a longer lifetime when compared to films containing the molecular material, which we ascribe to the charges being able to sample more than one chromophore and thus reduce recombination events.

Research Organization:
National Renewable Energy Laboratory (NREL), Golden, CO (United States)
Sponsoring Organization:
USDOE Office of Energy Efficiency and Renewable Energy (EERE), Office of Renewable Energy. Solar Energy Technologies Office; USDOE
Grant/Contract Number:
AC36-08GO28308; AC36-08-GO28038
OSTI ID:
1424894
Alternate ID(s):
OSTI ID: 1496431
Report Number(s):
NREL/JA-5900-68879
Journal Information:
Organic Electronics, Vol. 55, Issue C; ISSN 1566-1199
Publisher:
ElsevierCopyright Statement
Country of Publication:
United States
Language:
English

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Cited By (1)

Synthesis of a new W-type of functional polymer for improving intermolecular charge transfer processes at donor/acceptor interfaces journal July 2018

Figures / Tables (9)

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14 SOLAR ENERGY
42 ENGINEERING
organic photovoltaics
non-fullerene acceptor
synthesis
charge generation