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Molecular Donor–Acceptor Dyads for Efficient Single‐Material Organic Solar Cells
Author(s) -
Lucas Sebastian,
Kammerer Jochen,
Pfannmöller Martin,
Schröder Rasmus R.,
He Yakun,
Li Ning,
Brabec Christoph J.,
Leydecker Tim,
Samorì Paolo,
Marszalek Tomasz,
Pisula Wojchiech,
MenaOsteritz Elena,
Bäuerle Peter
Publication year - 2021
Publication title -
solar rrl
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.544
H-Index - 37
ISSN - 2367-198X
DOI - 10.1002/solr.202000653
Subject(s) - organic solar cell , materials science , acceptor , fullerene , photoactive layer , organic semiconductor , ambipolar diffusion , lamellar structure , chemical physics , solar cell , thermal stability , optoelectronics , nanotechnology , photochemistry , polymer solar cell , chemistry , polymer , organic chemistry , electron , physics , quantum mechanics , composite material , condensed matter physics
Single‐material organic solar cells (SMOSCs) promise several advantages with respect to prospective applications in printed large‐area solar foils. Only one photoactive material has to be processed and the impressive thermal and photochemical long‐term stability of the devices is achieved. Herein, a novel structural design of oligomeric donor–acceptor (D–A) dyads 1 – 3 is established, in which an oligothiophene donor and fullerene acceptor are covalently linked by a flexible spacer of variable length. Favorable optoelectronic, charge transport, and self‐organization properties of the D–A dyads are the basis for reaching power conversion efficiencies up to 4.26% in SMOSCs. The dependence of photovoltaic and charge transport parameters in these ambipolar semiconductors on the specific molecular structure is investigated before and after post‐treatment by solvent vapor annealing. The inner nanomorphology of the photoactive films of the dyads is analyzed with transmission electron microscopy (TEM) and grazing‐incidence wide‐angle X‐ray scattering (GIWAXS). Combined theoretical calculations result in a lamellar supramolecular order of the dyads with a D–A phase separation smaller than 2 nm. The molecular design and the precise distance between donor and acceptor moieties ensure the fundamental physical processes operative in organic solar cells and provide stabilization of D–A interfaces.