Give it a tweak: A novel oxidizing directing group was developed for a rhodium(III)-catalyzed CH functionalization of N-phenoxyacetamides with alkynes. A small change in the reaction conditions leads to either ortho-hydroxyphenyl-substituted enamides or cyclization to deliver benzofurans with high selectivity (see scheme; Cp*=C5 Me5 ).

counterparts and is very attractive for developing semitransparent organic solar cells (ST-OSCs), which have great potential application in building integrated photovoltaic, agricultural greenhouse, car window, and so on. [5,6] Different from opaque device that is concerned mostly with power conversion efficiency (PCE), ST-OSCs also value the transparency in the visible region and adopt average visible transmittance (AVT) to assess their see-through function. [7] However, there is a trade-off relationship between the see-through function and photovoltaic performances since enhancing the light transmission generally leads to lower amount of photons to be utilized. Therefore, efforts including material designing and device engineering are widely employed to reconcile the intrinsic contradiction between AVT and PCE. [8][9][10][11][12][13][14][15][16] Ideally, the photon-absorbing materials in ST-OSCs should have the main absorption in the NIR region and weak absorption in the visible region. [17] Previously, various narrow bandgap polymer donors were synthesized and matched with fullerene acceptors in ST-OSCs. [18,19] Recently, with the aid of advances in materials designing of NIR-absorbing non-fullerene electron acceptors, the PCEs of ST-OSCs have already surpassed 14%. [20,21] Meanwhile, optical engineering technologies, including photonic crystals, [22,23] antireflective device structures, [24,25] or optical microcavity structures, [26,27] have been applied to improve the PCEs and optimize the transmission spectra with deliberately designed layout but energy-consuming process. Other strategies, including multi-component, [28,29] sequentially deposited active layer [30,31] and thickness optimization [20] are also implemented to regulate photon harvesting range and improve PCEs in these fields.More directly, lowering the large-bandgap donor content in bulk-heterojunction (BHJ) has been demonstrated as a facile strategy to tune the transmittance spectrum of active layer. [32][33][34] The AVTs of D18-Cl:Y6-1O films have been continuously changed from 30.3% to 68.0% through ranging the donor and acceptor weight ratio (D:A ratio) from 1.1:1.6 to 0.1:1.6. [4] These previous works imply the feasibility of achieving high AVT from low-donor content ST-OSCs. Nevertheless, the performance optimization of OSCs with dilute donors still remains a challenge, mainly originating from the imbalanced charge Semitransparent organic solar cells (ST-OSCs) have promising prospects for building or vehicle integrated solar energy harvesting with energy generation and see-through function. How to achieve both an adequate average visible transmittance (AVT) and high-power conversion efficiency (PCE) is always the key issue. Herein, a simple but effective strategy for constructing high performance ST-OSCs by introducing a small molecule [2-(9-H-Carbazol-9-yl) ethyl] phosphonic acid (2PACz) into a low-donor content active layer is reported. The fill factor is improved from 70.5% to 75.5% and correlated to the mitigated charge recombination a...

By using an oxidizing directing group, a mild, efficient Rh(III) catalyzed C-H olefination reaction between N-phenoxyacetamides and alkenes was developed. This reaction provided a straightforward way for the synthesis of ortho-alkenyl phenols, and the directing group is traceless in the product.

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The development of hole‐transport materials (HTMs) with high mobility, long‐term stability, and comprehensive passivation is significant for simultaneously improving the efficiency and stability of perovskite solar cells (PVSCs). Herein, two donor–acceptor (D–A) conjugated polymers PBTI and PFBTI with alternating benzodithiophene (BDT) and bithiophene imide (BTI) units are successfully developed with desirable hole mobilities due to the good planarity and extended conjugation of molecular backbone. Both copolymers can be employed as HTMs with suitable energy levels and efficient defect passivation. Shortening the alkyl chain of the BTI unit and introducing fluorine atoms on the BDT moiety effectively enhances hole mobility and hydrophobicity of the HTMs, leading to improved efficiency and stability of PVSCs. As a result, the organic–inorganic hybrid PVSCs with PFBTI as the HTM deliver a power conversion efficiency (PCE) of 23.1% with enhanced long‐term operational and ambient stability, which is one of the best efficiencies reported for PVSCs with dopant‐free polymeric HTMs to date. Moreover, PFBTI can be applied in inorganic PVSCs and perovskite/organic tandem solar cells, achieving a high PCE of 17.4% and 22.2%, respectively. These results illustrate the great potential of PFBTI as an efficient and widely applicable HTM for cost‐effective and stable PVSCs.

A mild, regiocontrolled coupling of aromatic and vinylic amides with α-allenols to form γ-lactams via rhodium(III)-catalyzed C-H activation has been demonstrated. This [4 + 1] annulation reaction provides an efficient method for the synthesis of isoindolinones and 1,5-dihydro-pyrrol-2-ones bearing a tetrasubstituted carbon atom α to the nitrogen atom with good functional group tolerance. The hydroxyl group in the allene substrate is essential in controlling the chemo- and regioselectivity of the reaction probably by coordination interaction with the rhodium catalyst.

Colloidal quantum wells (CQWs) have emerged as a promising family of two-dimensional (2D) optoelectronic materials with outstanding properties, including ultranarrow luminescence emission, nearly unity quantum yield, and large extinction coefficient. However, the performance of CQWs-based light-emitting diodes (CQW-LEDs) is far from satisfactory, particularly for deep red emissions (≥660 nm). Herein, high efficiency, ultra-low-efficiency roll-off, high luminance, and extremely saturated deep red CQW-LEDs are reported. A key feature for the high performance is the understanding of charge dynamics achieved by introducing an efficient electron transport layer, ZnMgO, which enables balanced charge injection, reduced nonradiative channels, and smooth films. The CQW-LEDs based on (CdSe/CdS)@(CdS/CdZnS) ((core/crown)@(colloidal atomic layer deposition shell/hot injection shell)) show an external quantum efficiency of 9.89%, which is a record value for 2D nanocrystal LEDs with deep red emissions. The device also exhibits an ultra-low-efficiency roll-off and a high luminance of 3853 cd m −2 . Additionally, an exceptional color purity with the CIE coordinates of (0.719, 0.278) is obtained, indicating that the color gamut covers 102% of the International Telecommunication Union Recommendation BT 2020 (Rec. 2020) standard in the CIE 1931 color space, which is the best for CQW-LEDs. Furthermore, an active-matrix CQW-LED pixel circuit is demonstrated. The findings imply that the understanding of charge dynamics not only enables high-performance CQW-LEDs and can be further applied to other kinds of nanocrystal LEDs but also is beneficial to the development of CQW-LEDs-based display technology and related integrated optoelectronics.

By using an itrone as the oxidizing directing group,amild, practical and efficientr hodium(III)-catalyzed C À Hf unctionalization for the synthesis of indole derivatives hasb een developed. This reactiono bviates the need for an externalo xidant and showsg ood functional group tolerance. Thee mployment of as terically hinderedM es group on the carbon center of the nitrone is crucial to produce indoles in high yield.