Rational molecular and device design enables organic solar cells approaching 20% efficiency

Abstract

For organic solar cells to be competitive, the light-absorbing molecules should simultaneously satisfy multiple key requirements, including weak-absorption charge transfer state, high dielectric constant, suitable surface energy, proper crystallinity, etc. However, the systematic design rule in molecules to achieve the abovementioned goals is rarely studied. In this work, guided by theoretical calculation, we present a rational design of non-fullerene acceptor o-BTP-eC9, with distinct photoelectric properties compared to benchmark BTP-eC9. o-BTP-eC9 based device has uplifted charge transfer state, therefore significantly reducing the energy loss by 41 meV and showing excellent power conversion efficiency of 18.7%. Moreover, the new guest acceptor o-BTP-eC9 has excellent miscibility, crystallinity, and energy level compatibility with BTP-eC9, which enables an efficiency of 19.9% (19.5% certified) in PM6:BTP-C9:o-BTP-eC9 based ternary system with enhanced operational stability.

Over 19.2% efficiency of layer-by-layer organic photovoltaics enabled by a highly crystalline material as an energy donor and nucleating agent

“…Transient photovoltage (TPV) and transient photocurrent (TPC) characterizations were carried out to further understand the charge carrier dynamic process of LbL OPVs. 50,51 TPV and TPC decay curves of the typical LbL OPVs are depicted in Fig. 5b and Fig.…”

Conjugated polymers with near-infrared (NIR) optical absorption: structural design considerations and applications in organic electronics

“…However, the PCE for APSCs still falls behind donor polymer:acceptor small-molecule blends, which have certified PCEs approaching 20%. 295 As with ECDs, the development of flexible and stretchable OPVs with uncompromised performance metrics remains a continued challenge. It is foreseeable that the continued exploration and incorporation of new functionalities, such as hydrogen bonding groups or moieties capable of cross-linking, will assist in the development of more mechanically robust NIR-CPs.…”

Polythiophene and its derivatives for all-polymer solar cells

“…9–18 The power conversion efficiency (PCE) of high-performance OSCs is rapidly exceeding 20%, propelled by breakthroughs in molecular design and device optimization. 19–24 However, these high-performance materials typically feature complex chemical structures and involve complicated synthesis steps, leading to high costs. 25 Moreover, the inherent difficulties in scaling up may constrain their future practical applications.…”