Low-temperature-processed inverted perovskite solar cells (PVSCs) attract increasing attention because they can be fabricated on both rigid and flexible substrates. For this devices, holetransporting layers (HTLs) play an important role in achieving efficient and stable inverted PVSCs by adjusting the anodic work function, hole extraction, and interfacial charge recombination. Here, we report the use of a low-temperature (≤ 150 °C) solution-processed ultrathin film of poly[(9,9-dioctylfluorenyl-2,7-diyl)-co-(4,4′-(N-(4-secbutylphenyl) diphenylamine)] (TFB) as an HTL in one-stepprocessed CH 3 NH 3 PbI 3 (MAPbI 3 )-based inverted PVSCs. The fabricated device exhibits power conversion efficiency (PCE) as high as 20.2% when measured under AM 1.5 G illumination. This PCE makes them one of the MAPbI 3 -based inverted PVSCs that have the highest efficiency reported to date. Moreover, this inverted PVSC also shows good stability, which can retain 90% of its original efficiency after 30 days of storage in ambient air.

Perovskite solar cells (PSCs) have made huge progress with a record power conversion efficiency of up to 25.8% (certified 25.5%) in the last decade. Hole transporting materials (HTMs) are essential...

A ternary strategy is considered to be an efficient and simple way to further enhance the performance of organic photovoltaics (OPVs). However, the “structure–performance” correlation of the third component in the ternary device has rarely been clearly understood from the aspect of the material’s eigenproperties. Herein, this relationship is investigated in depth by employing three asymmetric skeleton nonfullerene acceptors as the third component in the host system of PM6:BTP-eC9, respectively. Compared with TB-S and TB-S1, the alkoxy-substituted TB-S1-O possesses a more stable planar conformation, a higher surface energy, and a larger ordered stacking domain due to the existence of noncovalent conformational locking (O···H). Consequently, the PM6:BTP-eC9:TB-S1-O device exhibits the highest efficiency of 18.14% as compared with the devices based on PM6:BTP-eC9:TB-S (16.16%) and PM6:BTP-eC9:TB-S1 (16.18%). Most interestingly, only the PM6:BTP-eC9:TB-S1-O device can maintain the positive effect of V OC improvement, because a significant reduction in nonradiative voltage loss can be observed in this device. Our systematic study reveals that alkoxy substitution on an asymmetric backbone is an efficient method to construct the third component for high-performance ternary organic solar cells.

A minimal non-radiative recombination energy loss of 0.21 eV is achieved for non-fullerene all-small-molecule organic solar cells.

An asymmetrically substituted squaraine ASQC bearing a 9-carbazyl substituent exhibits an extremely deep HOMO energy level of -5.46 eV and a relatively low bandgap of 1.65 eV, hence renders solution-processed organic solar cells with an impressive Voc of up to 1.12 V and a PCE of 2.82%.

The stability of organic solar cells (OSCs) is an urgent problem for commercialization. In this work, a novel asymmetric molecule TB-4Cl was designed and synthesized. Quantum chemical computations revealed that TB-4Cl has a larger dipole moment of 1.98 Debye than that of Y6, which can induce a stronger intermolecular interaction. Without thermal annealing, devices based on PM6:TB-4Cl achieved a higher efficiency of 14.67%. Impressively, all of the devices showed a negligible difference in power conversion efficiency (PCE) before and after thermal-annealing treatment. Compared to the unencapsulated PM6:Y6-based devices, PM6:TB-4Cl-based devices exhibited improved thermal and air stability, evidenced by retaining around 75% (TB-4Cl) and 60% (Y6) after being heated at 100 °C in nitrogen for 110 h and 65% (TB-4Cl) and 50% (Y6) in air for 92 h. This work indicates that an A−D 1 A′D 2 −A asymmetric molecule can be a promising candidate for achieving stable OSCs with high efficiency.

The strategy of isomerization plays a simple and effective role in optimizing the molecular configurations and improving the performance of binary organic solar cells (OSCs). However, the effect of isomerization...

Small molecule organic solar cells (SMOSCs) have received considerable attention in recent years. However, one of the key factors limiting the performance of SMOSCs is their large energy loss (E loss ), which is typically between 0.6 and 1.0 eV, and therefore significantly higher than those of perovskite solar cells and inorganic solar cells (E loss < 0.5 eV). Herein, we successfully report a new acceptor−donor−acceptor (A−D−A) type dimeric squaraine electron donor (D-IDTT-SQ) with a low optical band gap of 1.49 eV and deep HOMO energy level of −5.20 eV. Consequently, a high open-circuit voltage (V oc ) of 0.93 V with an impressive power conversion efficiency (PCE) of 7.05% is achieved for solution-processed bulk heterojunction SMOSCs, showing an E loss of only 0.56 eV. This is the first report wherein SMOSCs result in such a low E loss , while simultaneously exhibiting a considerably high V oc over 0.9 V and an excellent PCE above 7.0%.