Employing a Narrow-Band-Gap Mediator in Ternary Solar Cells for Enhanced Photovoltaic Performance

Abstract

Ternary organic solar cells (OSCs) provide a convenient and effective means to further improve the power conversion efficiency (PCE) of binary ones via composition control. However, the role of the third component remains to be explored in specific binary systems. Herein, we report ternary blend solar cells by adding the narrow-band-gap donor PCE10 as the mediator into the PBDB-T:IDTT-T binary blend system. The extended absorption, efficient fluorescence resonance energy transfer, enhanced charge dissociation, and induced tighter molecular packing of the ternary blend films enhance the photovoltaic properties of devices and deliver a champion PCE of 10.73% with an impressively high open-circuit voltage (V OC) of 1.03 V. Good miscibility and similar molecular packing behavior of the components guarantee the desired morphology in the ternary blend films, leading to solar cell devices with over 10% PCEs at a range of compositions. Our results suggest that ternary systems with properly aligned energy levels and overlapping absorption among the components hold great promises to further enhance the performance of corresponding binary ones.

Substitution Effect on Thiobarbituric Acid End Groups for High Open-Circuit Voltage Non-Fullerene Organic Solar Cells

“…A small energy offset between the LUMO levels of the donor and acceptors (<0.20 eV) is observed, though it has been shown that such a small offset can efficiently drive charge separation in nonfullerene acceptor based bulk heterojunctions. [39][40][41][42] 43 The effective charge transfer between the PCE10 donor and acceptors is confirmed by photoluminescence (PL) spectroscopy (Figure 1b). An obvious decrease in the intensity of the PCE10 fluorescence spectrum upon mixing with acceptors 3a, 3b, and 3c…”

“…An energy level diagram compares the IDTT-TBTA acceptors to the donor polymer PCE10 (Figure b), showing the right alignment of the HOMO and LUMO levels of PCE10 with those of the acceptors (Table ). A small energy offset between the LUMO levels of the donor and acceptors (<0.20 eV) is observed, though it has been shown that such a small offset can efficiently drive charge separation in non-fullerene-acceptor-based bulk heterojunctions. − …”

High‐Performance Ternary Polymer Solar Cells Enabled by a New Narrow Bandgap Nonfullerene Small Molecule Acceptor with a Higher LUMO Level

“…[13] However, the narrow absorption spectra, amorphous morphology, and relatively strong recombination of the photovoltaic materials are hindrances to improve efficiencies of organic photovoltaics (OPVs). To this end, ternary and quaternary strategies [14][15][16][17] have been proposed. Especially, ternary solar cells taking a third component as guest molecules (acceptor or donor materials) have attracted much attention.…”

Non-fullerene acceptor alloy strategy enabling stable ternary polymer solar cells with efficiency of 17.74%

“…In today's diversified field of solar cells, organic solar cells (OSCs) that can be prepared simply by a solution method have attracted attention because of the significant merits of lightweight, low cost, flexibility, and translucent preparation. [1][2][3][4] In recent years, with the emergence of novel high-efficiency organic photovoltaic materials (such as D18, Y6, etc. ), the performance of OSCs has been rapidly optimized.…”