Developing dopant-free hole transporting layers (HTLs) is critical in achieving high-performance and robust state-of-the-art perovskite photovoltaics, especially for the air-sensitive tin-based perovskite systems. The commonly used HTLs require hygroscopic dopants and additives for optimal performance, which adds extra cost to manufacturing and limits long-term device stability. Here we demonstrate the use of a novel tetrakis-triphenylamine (TPE) small molecule prepared by a facile synthetic route as a superior dopant-free HTL for lead-free tin-based perovskite solar cells. The best-performing tin iodide perovskite cells employing the novel mixed-cation ethylenediammonium/formamidinium with the dopant-free TPE HTL achieve a power conversion efficiency as high as 7.23%, ascribed to the HTL's suitable band alignment and excellent hole extraction/collection properties. This efficiency is one of the highest reported so far for tin halide perovskite systems, highlighting potential application of TPE HTL material in low-cost high-performance tin-based perovskite solar cells.
The majority of lysosomal enzymes are targeted to the lysosome by post-translational tagging with N-glycans terminating in mannose-6-phosphate (M6P) residues. Some current enzyme replacement therapies (ERTs) for lysosomal storage disorders are limited in their efficacy by the extent to which the recombinant enzymes bear the M6P-terminated glycans required for effective trafficking. Chemical synthesis was combined with endo-β-N-acetylglucosaminidase (ENGase) catalysis to allow the convergent synthesis of glycosyl amino acids bearing M6P residues. This approach can be extended to the remodeling of proteins, as exemplified by RNase. The powerful synergy of chemical synthesis and ENGase-mediated biocatalysis enabled the first synthesis of a glycoprotein bearing M6P-terminated N-glycans in which the glycans are attached to the peptide backbone by entirely natural linkages.
Developing efficient interfacial hole transporting materials (HTMs) is crucial for achieving high-performance Pb-free Sn-based halide perovskite solar cells (PSCs). Here, we report a new series of benzodithiophene (BDT)-based organic small molecules containing tetra-and This article is protected by copyright. All rights reserved. 2 di-triphenyl amine donors via a straightforward and scalable synthetic route. The thermal, optical, and electrochemical properties of two BDT-based molecules are shown to be structurally and energetically suitable to serve as HTMs for Sn-based perovskite solar cells.We report here that ethylenediammonium/formamidinium tin iodide solar cells using BDT-based HTMs deliver a champion power conversion efficiency (PCE) up to 7.59%, outperforming analogous reference solar cells using traditional and expensive HTMs. Thus, these BDT-based molecules are promising candidates as HTMs for the fabrication of high-performance Sn-based perovskite solar cells.
A series of dialkylated dithienothiophenoquinoids (DTTQs), end‐functionalized with dicyanomethylene units and substituted with different alkyl chains, are synthesized and characterized. Facile one‐pot synthesis of the dialkylated DTT core is achieved, which enables the efficient realization of DTTQs as n‐type active semiconductors for solution‐processable organic field effect transistors (OFETs). The molecular structure of hexyl substituted DTTQ‐6 is determined via single‐crystal X‐ray diffraction, revealing DTTQ is a very planar core. The DTTQ cores form a “zig‐zag” linking layer and the layers stack in a “face‐to‐face” arrangement. The very planar core structure, short core stacking distance (3.30 Å), short intermolecular SN distance (2.84 Å), and very low lying lowest unoccupied molecular orbital energy level of −4.2 eV suggest that DTTQs should be excellent electron transport candidates. The physical and electrochemical properties as well as OFETs performance and thin film morphologies of these new DTTQs are systematically studied. Using a solution‐shearing method, DTTQ‐11 exhibits n‐channel transport with the highest mobility of up to 0.45 cm2 V−1 s−1 and a current ON/OFF ratio (ION/IOFF) greater than 105. As such, DTTQ‐11 has the highest electron mobility of any DTT‐based small molecule semiconductors yet discovered combined with excellent ambient stability. Within this family, carrier mobility magnitudes are correlated with the alkyl chain length of the side chain substituents of DTTQs.
New 3,3'-dithioalkyl-2,2'-bithiophene (SBT)-based small molecular and polymeric semiconductors are synthesized by end-capping or copolymerization with dithienothiophen-2-yl units. Single-crystal, molecular orbital computations, and optical/electrochemical data indicate that the SBT core is completely planar, likely via S(alkyl)⋯S(thiophene) intramolecular locks. Therefore, compared to semiconductors based on the conventional 3,3'-dialkyl-2,2'-bithiophene, the resulting SBT systems are planar (torsional angle <1°) and highly π-conjugated. Charge transport is investigated for solution-sheared films in field-effect transistors demonstrating that SBT can enable good semiconducting materials with hole mobilities ranging from ≈0.03 to 1.7 cm V s . Transport difference within this family is rationalized by film morphology, as accessed by grazing incidence X-ray diffraction experiments.
Three new organic semiconductors with alkyl chain-substituted tetrathienoacene (TTAR) as the central core and both ends capped with thiophene (DT-TTAR), thienothiophene (DTT-TTAR) and dithienothiophene (DDTT-TTAR) have been synthesized and characterized for organic field effect transistor (OFET) applications. A hole mobility of 0.81 cm V s was achieved for the DDTT-TTAR film, which represents the highest mobility yet found for a solution-processable p-type TTAR-based small molecular semiconductors.
Four soluble dialkylated tetrathienoacene (TTAR)-based small molecular semiconductors featuring the combination of a TTAR central core, π-conjugated spacers comprising bithiophene (bT) or thiophene (T), and with/without cyanoacrylate (CA) end-capping moieties are synthesized and characterized. The molecule DbT-TTAR exhibits a promising hole mobility up to 0.36 cm 2 V −1 s −1 due to the enhanced crystallinity of the microribbon-like films. Binary blends of the p-type DbT-TTAR and the n-type dicyanomethylene substituted dithienothiophene-quinoid (DTTQ-11) are investigated in terms of film morphology, microstructure, and organic field-effect transistor (OFET) performance. The data indicate that as the DbT-TTAR content in the blend film increases, the charge transport characteristics vary from unipolar (electron-only) to ambipolar and then back to unipolar (hole-only). With a 1:1 weight ratio of DbT-TTAR/DTTQ-11 in the blend, well-defined pathways for both charge carriers are achieved and resulted in ambipolar transport with high hole and electron mobilities of 0.83 and 0.37 cm 2 V −1 s −1 , respectively. This study provides a viable way for tuning microstructure and charge carrier transport in small molecules and their blends to achieve high-performance solution-processable OFETs.
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