Parallel Bulk‐Heterojunction Solar Cell by Electrostatically Driven Phase Separation

Abstract

Thermal co-evaporation of C(60) fullerene and two merocyanine dyes affords bulk heterojunction solar cells with improved short-circuit currents and power conversion efficiencies in comparison with the respective single donor cells. These results are rationalized by the formation of three distinct subphases driven by differences in molecular shape and electrostatic interactions.

Status and prospects for ternary organic photovoltaics

“…Instead of bulk heterojunction structures, ternary solar cells based on small molecules generally adopt bilayer or trilayer architectures where donor and acceptor form independent layers. Parallel-like small-molecule ternary solar cells were reported through the co-evaporation of two merocyanine dyes as the donor layer and C 60 as the acceptor layer 69 . Phase separations were controlled by dipolar intermolecular forces.…”

Interrelation between Crystal Packing and Small‐Molecule Organic Solar Cell Performance

“…The bulk characteristics in turn depend on non-bonding intermolecular interactions, which lead to specific molecular order, packing, and morphology in the solid state. [4][5][6] A good performance of BHJ SMOSCs is only guaranteed if an interpenetrating network of the oligomeric donor (D) and an electron-acceptor (A), typically a fullerene derivative, is formed at the nanoscale as the photoactive layer. [7][8][9] Moreover, the size of the D and A homophases is crucially important for the diffusion of excitons to the D-A interface and after charge separation for effective charge transport to the electrodes.…”

Organische Chemie 2011

“…Für weitere Steigerungen müssen vor allem Systeme entwickelt werden, die eine spektral breitere Lichtabsorption bei gleich bleibenden Schichtdicken aufweisen. Einen eleganten Ansatz hierzu präsentierten Meerholz und Würthner: Für vakuumprozessierte ternäre Solarzellen aus den beiden Merocyaninen (2) und (3) sowie C60 erhielten sie signifikant höhere Energieumwandlungseffizienzen als für die jeweiligen Zwei‐Komponenten‐Systeme 2…”