mobility. [18] However, P-OSCs have a drawback in batch-to-batch reproducibility of donor polymers, which potentially limits the mass deployment of OSCs. [19] Compared to P-OSCs, small-molecule based OSCs (SM-OSCs) are more attractive in commercialization because of well-defined molecular structures, [20][21][22] simpler synthesis and purification, [23][24][25] and low batch-to-batch variations. [26][27][28][29] With the SM donors developed, the state-of-the-art SM-OSCs show similar PCEs as those obtained for P-OSCs (over 11%) using fullerene derivative, PCBM, as the electron acceptor. [19,[30][31][32][33] However, when the NFSM acceptors were used in nonfullerene-based small molecule organic solar cells (NFSM-OSCs) their PCE can only reach slightly over 10% [34][35][36][37] which is much lower than those obtained for nonfullerene polymer solar cells (NFP-OSCs) with usually PCE over 13%. [38,39] The progress of NFSM-OSCs is strongly lagged behind their polymer counterparts.The PCE of an OSC is determined by three parameters, opencircuit voltage (V oc ), short-circuit current density (J sc ), and fill factor (FF). The main reason for the low PCE in NFSM-OSCs is due to their relative low J sc and FF. [40,41] As shown in Table S1 (Supporting Information), all of the efficient NFP-OSCs with PCE over 14% show high J sc (>20 mA cm −2 ) and high FF In this paper, two near-infrared absorbing molecules are successfully incorporated into nonfullerene-based small-molecule organic solar cells (NFSM-OSCs) to achieve a very high power conversion efficiency (PCE) of 12.08%. This is achieved by tuning the sequentially evolved crystalline morphology through combined solvent additive and solvent vapor annealing, which mainly work on ZnP-TBO and 6TIC, respectively. It not only helps improve the crystallinity of the ZnP-TBO and 6TIC blend, but also forms multilength scale morphology to enhance charge mobility and charge extraction. Moreover, it simultaneously reduces the nongeminate recombination by effective charge delocalization. The resultant device performance shows remarkably enhanced fill factor and J sc . These result in a very respectable PCE, which is the highest among all NFSM-OSCs and all small-molecule binary solar cells reported so far.

and droplet-based electricity generator (DEG). [9] However, inherent flaws exist in current approaches. Reverse electrowetting energy harvesting devices always need external voltages. [1] Triboelectric nanogenerator (TENG), [10,11] which was first invented in 2012 by Wang and coworkers, [12,13] has provided a passive energy harvesting approach. But the performance of TENG is limited by the low density and poor stability of surface charges on tribo-layers. High surface charge density could only be achieved in vacuum environment [14] or by utilizing external pumping or excitation sources. [11,15] The droplet energy harvesting efficiency of the conventional TENG was only 0.01%. [5] Recently, Z. K. Wang and coworkers have reported a water dropbased electric generator, DEG, [9] showing significantly enhanced energy harvesting efficiency to 2.2%. Nevertheless, the energy harvesting efficiency of DEG is still limited by the density and stability of charges generated by triboelectrification during drop impact. The maximum surface charge density of DEG displayed around 0.184 mC m −2 (49.8 nC for 2.7 cm 2). [9] The surface charges in DEG were superior stability compared to the conventional TENG, although the charge density still degraded in a harsh environment with 100% humidity. Moreover, the efficiency greatly dropped with increasing salt Strategies toward harvesting energy from water movements are proposed in recent years. Reverse electrowetting allows high efficiency energy generation, but requires external electric field. Triboelectric nanogenerators, as passive energy harvesting devices, are limited by the unstable and low density of tribo-charges. Here, a charge trapping-based electricity generator (CTEG) is proposed for passive energy harvesting from water droplets with high efficiency. The hydrophobic fluoropolymer films utilized in CTEG are pre-charged by a homogeneous electrowetting-assisted charge injection (h-EWCI) method, allowing an ultrahigh negative charge density of 1.8 mC m −2. By utilizing a dedicated designed circuit to connect the bottom electrode and top electrode of a Pt wire, instantaneous currents beyond 2 mA, power density above 160 W m −2 , and energy harvesting efficiency over 11% are achieved from continuously falling water droplets. CTEG devices show excellent robustness for energy harvesting from water drops, without appreciable degradation for intermittent testing during 100 days. These results exceed previously reported values by far. The approach is not only applicable for energy harvesting from water droplets or wave-like oscillatory fluid motion, but also opens up avenues toward other applications requiring passive electric responses, such as diverse sensors and wearable devices.

A highly crystalline acceptor (4TIC) was used as the additional non-fullerene acceptor to construct ternary small-molecule organic solar cells. The addition of 4TIC not only significantly enhances the crystallinity of the blend film but also maintains the desired face-on orientation in the proper multi-length scale morphology to improve both charge extraction and recombination in devices. The ternary devices showed a remarkably enhanced short-circuit current density and fill factor, resulting in a high power conversion efficiency of 15.88%.

We use a combination of high-speed video imaging and electrical measurements to study the direct conversion of the impact energy of water drops falling onto an electrically precharged solid surface into electrical energy. Systematic experiments at variable impact conditions (initial height; impact location relative to electrodes) and electrical parameters (surface charge density; external circuit resistance; fluid conductivity) allow us to describe the electrical response quantitatively without any fit parameters based on the evolution of the drop-substrate interfacial area. We derive a scaling law for the energy harvested by such "nanogenerators" and find that optimum efficiency is achieved by matching the timescales of the external electrical energy harvesting circuit and the hydrodynamic spreading process.