Recently, non-fullerene n-type organic semiconductors have attracted significant attention as acceptors in organic photovoltaics (OPVs) due to their great potential to realize high-power conversion efficiencies. The rational design of the central fused ring unit of these acceptor molecules is crucial to maximize device performance. Here, we report a new class of non-fullerene acceptor, Y6, that employs a ladder-type electron-deficient-core-based central fused ring (dithienothiophen[3.2-b]-pyrrolobenzothiadiazole) with a benzothiadiazole (BT) core to fine-tune its absorption and electron affinity. OPVs made from Y6 in conventional and inverted architectures each exhibited a high efficiency of 15.7%, measured in two separate labs. Inverted device structures were certified at Enli Tech Laboratory demonstrated an efficiency of 14.9%. We further observed that the Y6-based devices maintain a high efficiency of 13.6% with an active layer thickness of 300 nm. The electron-deficient-core-based fused ring reported in this work opens a new door in the molecular design of high-performance acceptors for OPVs.

Narrow bandgap n‐type organic semiconductors (n‐OS) have attracted great attention in recent years as acceptors in organic solar cells (OSCs), due to their easily tuned absorption and electronic energy levels in comparison with fullerene acceptors. Herein, a new n‐OS acceptor, Y5, with an electron‐deficient‐core‐based fused structure is designed and synthesized, which exhibits a strong absorption in the 600–900 nm region with an extinction coefficient of 1.24 × 105 cm−1, and an electron mobility of 2.11 × 10−4 cm2 V−1 s−1. By blending Y5 with three types of common medium‐bandgap polymers (J61, PBDB‐T, and TTFQx‐T1) as donors, all devices exhibit high short‐circuit current densities over 20 mA cm−2. As a result, the power conversion efficiency of the Y5‐based OSCs with J61, TTFQx‐T1, and PBDB‐T reaches 11.0%, 13.1%, and 14.1%, respectively. This indicates that Y5 is a universal and highly efficient n‐OS acceptor for applications in organic solar cells.

Poly(ethylene glycol) diacrylate (PEGDA) is introduced into the SnO 2 dispersion as the polymer framework to hinder the agglomeration. The PEGDA-modified SnO 2 acted as the electron transport layer (ETL) in n-i-p structured perovskite solar cells (pero-SCs). It is demonstrated that the PEGDA plays multifunctional roles in the enhancement of photovoltaic performance and stability against illumination and humility. First, the PEGDA-modified SnO 2 ETL is more uniform, and its energy level matched well with the perovskite, which could facilitate the carrier transport and reduce the energy loss. Second, PEGDA could passivate the defects at the interface between perovskite and ETL. Eventually, a power conversion efficiency (PCE) of 23.31% is achieved for the α-FAPbI 3 based pero-SCs. Most importantly, the unencapsulated devices maintained more than 90% of the initial PCE after 850 h continuous illumination (100 mW/cm 2 ). This study could provide insight for the low-cost, facile, and efficient interface modification for the pero-SCs.

All‐polymer solar cells (all‐PSCs) have drawn growing attention and achieved tremendous progress recently, but their power conversion efficiency (PCE) still lags behind small‐molecule‐acceptor (SMA)‐based PSCs due to the relative difficulty on morphology control of polymer photoactive blends. Here, low‐cost PTQ10 is introduced as a second polymer donor (a third component) into the PM6:PY‐IT blend to finely tune the energy‐level matching and microscopic morphology of the polymer blend photoactive layer. The addition of PTQ10 decreases the π–π stacking distance, and increases the π–π stacking coherence length and the ordered face‐on molecular packing orientation, which improves the charge separation and transport in the photoactive layer. Moreover, the deeper highest occupied molecular orbital energy level of the PTQ10 polymer donor than PM6 leads to higher open‐circuit voltage of the ternary all‐PSCs. As a result, a PCE of 16.52% is achieved for ternary all‐PSCs, which is one of the highest PCEs for all‐PSCs. In addition, the ternary devices exhibit a high tolerance of the photoactive layer thickness with high PCEs of 15.27% and 13.91% at photoactive layer thickness of ≈205 and ≈306 nm, respectively, which are the highest PCEs so far for all‐PSCs with a thick photoactive layer.

The boom in visible light photoredox catalysis (VLPC) research has demonstrated that this novel synthetic approach is here to stay. VLPC enables reactive radical intermediates to be catalytically generated at ambient temperature, a feat not generally allowed through traditional pyrolysis- or radical initiator-based methodologies. VLPC has vastly extended the range of substrates and reaction schemes that have been traditionally the domain of radical reactions. In this review the photophysics background of VLPC will be briefly discussed, followed by a report on recent inroads of VLPC into decarboxylative couplings and radical C-H functionalization of aromatic compounds. The bulk of the review will be dedicated to advances in synergistic catalysis involving VLPC, namely the combination of photoredox catalysis with organocatalysis, including β-functionalization of carbonyl groups, functionalization of weak aliphatic C-H bonds, and anti-Markovnikov hydrofunctionalization of alkenes; dual catalysis with gold or with nickel, photoredox catalysis as an oxidation promoter in transition metal catalysis, and acid-catalyzed enantioselective radical addition to π systems.

Recently, a random ternary copolymerization strategy has become a promising and efficient approach to develop high‐performance polymer donors for polymer solar cells (PSCs). In this study, a low‐cost electron‐withdrawing unit, 2,5‐bis(4‐(2‐ethylhexyl)thiophen‐2‐yl)pyrazine (PZ‐T), is incorporated into the polymer backbone of PM6 as the third component, and three D‐A1‐D‐A2 type terpolymers PMZ‐10, PMZ‐20, and PMZ‐30 are synthesized by the random copolymerization strategy, with the PZ‐T proportion of 10%, 20%, and 30%, respectively. The terpolymers exhibit downshifted highest occupied molecular orbital energy levels than PM6, which is beneficial for obtaining higher open‐circuit voltage (Voc) of the PSCs with the polymer as a donor. Importantly, the PSCs based on PMZ‐10:Y6 demonstrate efficient exciton dissociation, higher and balanced electron/hole mobilities, desirable aggregation, and high power conversion efficiency of 18.23%, which is the highest efficiency among the terpolymer‐based PSCs so far. The results indicate that the ternary copolymerization strategy with PZ‐T as the second A‐unit is an efficient approach to further improve the photovoltaic performance and reduce the synthetic cost of the D‐A copolymer donors.

We further describe a protocol for the investigation of surface charge with scanning ion conductance microscopy. The protocol measures current-voltage curves at positions close to and far from the surface of interest and reports the differential response. The data can be interpreted in terms of rectification ratios, an intuitive quantity for such studies. With this protocol, we further investigate the effect of electrolyte concentration and study the influence of scan potential on surface charge measurement on chemically modified surfaces.Charge is a fundamental interfacial property that governs physical and chemical interactions at surfaces. The workings of catalysts, [1] sensors, [2] separation devices, [3] biological interfaces, [4] and colloidal systems, [5] are well known to be strongly influenced by surface charge, typically present in the form of protonated or deprotonated chemical moieties. Directly measuring charge in situ, especially for small (micro/nanoscale), heterogenous charge distributions presents an interesting and important challenge for electroanalytical chemistry. Here, we communicate studies in mapping interfacial charge with scanning ion conductance microscopy (SICM) [6][7][8] and the influence of electrolyte concentration on the charge sensing mechanism.When immersed in electrolyte, a charged substrate attracts counter ions and forms an electrical double layer (EDL), a key process in the consideration of nearly all electrochemical systems. With SICM, a small pipette, typically made of quartz or borosilicate, is brought near a surface of interest. The pipette is filled with electrolyte and an electrode (Ag/AgCl, WE) is placed inside the pipette, with a second electrode (RE) placed in the electrolyte solution (bath) surrounding the pipette and surface. Application of a potential between these two electrodes generates an ion current, with the dimensions of the pipette tip serving as a resistive element to the ion current. As the tip of the pipette is moved towards the surface, a distance dependent access resistance (R ac ) develops. With proper feedback methods, R ac can be used to control the vertical position of the pipette. If the tip of the pipette is small (e. g. a nanopipette), then the feedback regime occurs at distances where the EDL of the tip and the surface interact (typically on the order of the radius of the pipette opening), [9] and this interaction forms the basis for measuring or detecting the charge presented at the surface, as reflected in the EDL.Interactions between the ion current flowing through the tip of the nanopipette and the charge of a surface have been reported previously by our group [10][11][12] and others, [13][14][15][16][17][18][19][20] with charge mapping initially reported by Unwin and coworkers. [13] Charge mapping has been applied to chemically modified surfaces, [15] cell interfaces, [14,[16][17] chromosomes, [18] and supported lipid bilayers. [19,21] In previous studies, phase [13,15,17] or changes in apparent imaging height [19,21] have been used to in...

Chiral rhodium-bisoxazolinylphenyl acetate complexes exhibited high catalytic activity for the beta-boration of alpha,beta-unsaturated carbonyl compounds with bis(pinacolato)diboron in the presence of sodium t-butoxide with enantioselectivity up to 97%.