Non-fullerene acceptors have recently attracted tremendous interest because of their potential as alternatives to fullerene derivatives in bulk heterojunction organic solar cells. However, the power conversion efficiencies (PCEs) have lagged far behind those of the polymer/fullerene system, mainly because of the low fill factor (FF) and photocurrent. Here we report a novel perylene bisimide (PBI) acceptor, SdiPBI-Se, in which selenium atoms were introduced into the perylene core. With a well-established wide-band-gap polymer (PDBT-T1) as the donor, a high efficiency of 8.4% with an unprecedented high FF of 70.2% is achieved for solution-processed non-fullerene organic solar cells. Efficient photon absorption, high and balanced charge carrier mobility, and ultrafast charge generation processes in PDBT-T1:SdiPBI-Se films account for the high photovoltaic performance. Our results suggest that non-fullerene acceptors have enormous potential to rival or even surpass the performance of their fullerene counterparts.

A novel perylene bisimide (PBI) dimer-based acceptor material, SdiPBI-S, was developed. Conventional bulk-heterojunction (BHJ) solar cells based on SdiPBI-S and the wide-band-gap polymer PDBT-T1 show a high power conversion efficiency (PCE) of 7.16% with a high open-circuit voltage of 0.90 V, a high short-circuit current density of 11.98 mA/cm(2), and an impressive fill factor of 66.1%. Favorable phase separation and balanced carrier mobilites in the BHJ films account for the high photovoltaic performance. The results demonstrate that fine-tuning of PBI-based materials is a promising way to improve the PCEs of non-fullerene BHJ organic solar cells.

Two kinds of conjugated C3-symmetric perylene dyes, namely, triperylene hexaimides (TPH) and selenium-annulated triperylene hexaimides (TPH-Se), are efficiently synthesized. Both TPH and TPH-Se have broad and strong absorption in the region 300-600 nm together with suitable LUMO levels of about -3.8 eV. Single-crystal X-ray diffraction studies show that TPH displays an extremely twisted three-bladed propeller configuration and a unique 3D network assembly in which three PBI subunits in one TPH molecule have strong π-π intermolecular interactions with PBI subunits in neighboring molecules. The integration of selenophene to TPH endows TPH-Se with a more distorted propeller configuration and a more compact 3D network assembly due to the Se···O interactions. A single-crystal transistor confirms that both TPH and TPH-Se possess good electron-transport ability. TPH and TPH-Se acceptor-based solar cells show high power conversion efficiency of 8.28% and 9.28%, respectively, which mainly results from the combined properties of broad and strong absorption ability, appropriate LUMO level, desirable aggregation, high electron mobility, and good film morphology with the polymer donor.

This review provides a comprehensive understanding of the emerging 2D MXene electrode materials for supercapacitor application.

In this study, yolk-shell Ni@SnO composites with a designable interspace were successfully prepared by the simple acid etching hydrothermal method. The Ni@void@SnO composites were characterized by X-ray diffraction, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, scanning electron microscopy, and transmission electron microscopy. The results indicate that interspaces exist between the Ni cores and SnO shells. Moreover, the void can be adjusted by controlling the hydrothermal reaction time. The unique yolk-shell Ni@void@SnO composites show outstanding electromagnetic wave absorption properties. A minimum reflection loss (RL) of -50.2 dB was obtained at 17.4 GHz with absorber thickness of 1.5 mm. In addition, considering the absorber thickness, minimal reflection loss, and effective bandwidth, a novel method to judge the effective microwave absorption properties is proposed. On the basis of this method, the best microwave absorption properties were obtained with a 1.7 mm thick absorber layer (RL= -29.7 dB, bandwidth of 4.8 GHz). The outstanding electromagnetic wave absorption properties stem from the unique yolk-shell structure. These yolk-shell structures can tune the dielectric properties of the Ni@air@SnO composite to achieve good impedance matching. Moreover, the designable interspace can induce interfacial polarization, multiple reflections, and microwave plasma.