High‐Performance Small Molecule Organic Solar Cells Enabled by a Symmetric‐Asymmetric Alloy Acceptor with a Broad Composition Tolerance

Abstract

Using a combinatory blending strategy is demonstrated as a promising path for designing efficient organic solar cells (OSCs) by boosting the short‐circuit current density and fill factor. Herein, a high‐performance ternary all‐small molecule OSC (all‐SMOSCs) using a narrow‐bandgap alloy acceptor containing symmetric and asymmetric molecules (BTP‐eC9 and SSe‐NIC) and a wide‐bandgap small molecule donor MPhS‐C2 is reported. Introducing the synthesized SSe‐NIC into the MPhS‐C2:BTP‐eC9 host system can broaden the absorption spectrum, modulate energy offsets, and optimize the molecular packing of the host materials. After systematically optimizing the weight ratio of MPhS‐C2:BTP‐eC9:SSe‐NIC, a champion efficiency of 18.02% is achieved. Impressively, the ternary system not only delivered a broad composition tolerance with device efficiencies over 17% throughout the whole blend ratios, but also exhibited less non‐geminate recombination and energy loss, and better‐light‐soaking stability than the corresponding binary systems. This work promotes the development of high‐performance ternary all‐SMOSCs and heralds their brighter application prospects.

18.73% efficiency organic solar cells with a medium bandgap acceptor as a third component

“…1b), enabling efficient electron transfer in ternary films. 15,16 PM6, a wide bandgap donor polymer, strongly absorbs across a broad range from 300 to 700 nm. On the other hand, BTP-eC9, a low bandgap acceptor, possesses the capability of absorbing across 300 to 950 nm.…”

High-Performance All-Small-Molecule Organic Solar Cells Fabricated via Halogen-Free Preparation Process

“…Bulk-heterojunction (BHJ) organic solar cells (OSCs) have been regarded as a promising energy conversion technology due to their unique characteristics of lightweight, flexibility, and solution processability. − In recent years, the advent of narrow band-gap small-molecule acceptors (SMAs), particularly Y6 and its derivatives, has significantly improved the power conversion efficiencies (PCEs) of OSCs based on polymer donors and small-molecule acceptors, surpassing 19%. − Unlike polymer photovoltaic materials, small-molecule photovoltaic materials offer advantages such as precisely defined chemical structure, minimal batch-to-batch variations, and easy purification. − As a result, there has been a remarkable focus on all-small-molecule organic solar cells (ASM-OSCs), which have shown substantial advancements. Specifically, the PCEs of binary ASM-OSCs have exceeded 17%, while ternary ASM-OSCs have surpassed 18%. ,− …”

Enhanced Self-Stimulated Dissociation in Non-fullerene Layer-by-Layer Organic Solar Cells through Superimposed and Oriented Dipolar Polarization

“…Over the past decades, many efficient non-fullerene acceptors have been synthesized for organic solar cells (OSCs). − Non-fullerene acceptors, as the alternative to fullerene acceptors, have attracted increasing attention because they present good light harvesting capability and facile energy-level modulation. Recently, non-fullerene molecules have emerged as very promising electron acceptors in OSCs, and over 19% power conversion efficiency (PCE) in non-fullerene-based OSCs has been recorded, , which demonstrates a predictable and near-commercial PCE as compared to the PCE in fullerene-based OSCs.…”