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For achieving high-efficiency perovskite solar cells, it is almost always necessary to substantially passivate defects and protect the perovskite structure at its interfaces with charge transport layers. Such a modification generally involves the post-treatment of the deposited perovskite film by spin coating, which cannot meet the technical demands of scaling up the production of perovskite photovoltaics. In this work, we demonstrate one-step construction of buried and capped double 1D/3D heterojunctions without the need for any post-treatment, which is achieved through facile tetraethylammonium trifluoroacetate (TEATFA) prefunctionalization on the SnO 2 substrate. The functional TEATFA salt is first deposited onto the SnO 2 substrate and reacts on this buried interface. Once the FAPbI 3 perovskite precursor solution is dripped, a portion of the TEA + cations spontaneously diffuse to the top surface over film crystallization. The TEATFA-based water-resistant 1D/3D TEAPbI 3 /FAPbI 3 heterojunctions at both the buried and capped interfaces lead to much better photovoltaic performance and higher operational stability. Since this approach saves the need for any postsynthesis passivation, its feasibility for the fabrication of large-area perovskite photovoltaics is also showcased. Compared to ∼15% for a pristine 5 cm × 5 cm FAPbI 3 mini-module without postsynthesis passivation, over 20% efficiency is achieved following the proposed route, demonstrating its great potential for larger-scale fabrication with fewer processing steps., Competing Interests: The authors declare no competing financial interest., (© 2023 The Authors. Published by American Chemical Society.)

Perovskite photovoltaics with the advantages of facile fabrication and high efficiency have been the rising star in the field for a decade. Methylammonium lead triiodide (MAPbI 3 ) was the first widely studied perovskite to initiate the boom of perovskite photovoltaics, but it was later considered thermodynamically instable for commercialization. Here, we demonstrate that simple cesium (Cs) doping without any complicated process can form a stable MA-based perovskite with a widened bandgap, which may broaden the application of MA-based perovskites in tandem solar cells. A record-high efficiency of ≤22% is thus achieved for a 1.6 eV bandgap perovskite solar cell. This work not only provides a new stable and efficient pure iodide candidate as a 1.6 eV bandgap perovskite but also reveals that Cs incorporation can help improve the efficiency and stability of MA-based perovskites.

Upcycling plastic waste pollution for sustainable resources and energy is an ideal solution to plastic waste-related environmental issues. Polyethylene terephthalate (PET), one of the most prominent single-use daily plastics with up to millions of tons produced annually, has recently been explored with respect to chemical recycling to ameliorate its environmental impact. In this work, we report an electrochemical upcycling approach to electrocatalytic oxidation of PET hydrolysate using Cu-based nanowire catalysts. We demonstrate that the electrocatalyst can catalyze the ethylene glycol (EG) molecule derived from PET waste toward formate with high selectivity and exhibit a lower onset potential for EG oxidation than for water oxidation. Experimental and density functional theory calculation results reveal that the oxidation pathway of EG on CuO can selectively break the C-C bond to generate formic acid. This work sheds light on employing earth-abundant metal catalysts to convert PET plastic waste to produce valued chemicals and green hydrogen.

ConspectusOwing to the remarkable progress achieved over the past decade with research efforts from the perspectives of material synthesis, device configuration, and theoretical investigation, metal halide perovskites have emerged as a revolutionary class of light-absorbing semiconductors. The perovskite photovoltaic devices have demonstrated an impressive increase in power conversion efficiency. For single-junction perovskite solar cells, the value has risen from the initial one-digit maximum to the state-of-art record of 25.5%. Among various chemical and structural variations of perovskites, inorganic lead halides possess a more favorable operational stability and hold greater potential for perovskite/silicon tandem photovoltaics' top cells. At the initial stage of exploring all-inorganic perovskites for optoelectronic applications, many concepts, technical routes, and modification strategies were directly adopted from research on the more-developed field of organic-inorganic hybrid perovskite (OIHP). However, as understandings on inorganic perovskite deepen with research experience gained from both experimental and theoretical progression, it has been found that the difference between the asymmetric, volatile organic cations and the spherical, stable inorganic cations can lead to drastic changes on overall material properties and the subsequent device performances. In detail, the disparities reflect the crystalline and phase profiles of the material, the fabrication and passivation rationales of perovskite thin films, and the photophysics in the assembled optoelectronic devices. Therefore, the discussions of all-inorganic perovskites have their own exclusivity and are worthy of a specialized scrutinization.Here in this Account, the latest progress on the stabilization of inorganic lead halide perovskites for efficient photovoltaic applications is highlighted. A library of chemical compositions will be discussed with a focus on notable works about CsPbI 3 , which possesses a more favorable bandgap as a tandem to commercialized silicon solar cells. To underscore the influence of the crystal phase on the stability of inorganic perovskites, fundamental investigations regarding the chemical and physical properties, including experimental and theoretical studies, will be summarized as a means of phase control. The stability of inorganic lead halide perovskites can also be improved by the strategic introduction of external components to the light-absorbing layer, such as the incorporation of inorganic halides, organic cations, OIHPs with low dimension, etc. These strategies can synergistically improve the stability and efficiency of the fabricated devices from the perspectives of compositional tuning, dimensional engineering, surface termination, and low-dimension capping. On the basis of a careful examination and an analysis of works achieved in these categories from our group and others, we will then discuss some promising approaches toward achieving more stable and efficient photovoltaics using inorganic lead halide perovskites.

Achieving reduced defect density and efficient charge carrier extraction plays a vital role for efficient and stable perovskite solar cells (PSCs). Over the course of technical development, it is desired to use one single material or approach to synergistically passivate defects and enhance the charge extraction. In this work, we developed an effective strategy for obtaining efficient and stable PSCs via incorporating quasi-monolayer two-dimensional WSe 2 into the MAPbI 3 perovskite layer. The addition of WSe 2 helps with the formation of perovskite film with higher quality and also passivates the Pb-related defects through Pb-Se coordination bonding. MAPbI 3 /WSe 2 shows a more matched energy-level alignment between the perovskite layer and hole transport layer for accelerated hole extraction. Consequently, the performances of PSCs significantly improved with power conversion efficiency increase from 19.2% to 21.2% after the incorporation of WSe 2 . Accordingly, the MAPbI 3 /WSe 2 -based PSCs exhibit well-improved photostability with suppression of Pb 0 defect formation.

5-Ammonium valeric acid iodide (AVAI) has been widely known as a stabilizer to enhance the stability of MAPbI 3 perovskite, but its role and function is still under exploration. The typical 2D perovskites of AVA 2 PbI 4 have been proposed as the capping layer for stabilization. Here, a novel AVA-MA mixed-cation perovskite of AVAMAPbI 4 is found to show a more even and compact coverage than the typical 2D perovskite of AVA 2 PbI 4 . A simple post-treatment on MAPbI 3 films by using AVAI isopropanol solution can fabricate such a mixed-cation 2D perovskite capping layer on the MAPbI 3 sample. This AVAMAPbI 4 capping layer effectively passivates surface defects of MAPbI 3 perovskite films and reduces the charge-carrier recombination, enabling AVAI-MAPbI 3 perovskite films to exhibit improved stability against thermal and moisture stress. Finally, the AVAI-MAPbI 3 -based perovskite solar cells also show an enhanced photovoltaic performance with a champion PCE up to 20.05% with enhanced stability.

An effective LC-MS based method for online characterization of low abundant structural isomers of N-linked glycans in biological therapeutics was developed. N-linked glycans of a recombinant monoclonal antibody were released by PNGase F and labeled with 2-aminobenzamide (2-AB) fluorescent tag. The labeled glycans were analyzed by online ultraperformance liquid chromatography-hydrophilic interaction liquid chromatography (UPLC-HILIC) coupled with mass spectrometry (MS). The glycan structure was characterized by MS(n) fragmentation in negative ion mode followed by identification of the signature D ions. The assignment included monosaccharide sequence and linkage information. The developed method successfully characterized structural isomers of A1G1F (assigned as terminal sialic acid attached in the 1,6 branch at 2,3 position), and A1G1F' (assigned as terminal sialic acid attached in the 1,3 branch at 2,3 position). Moreover, using the same approach, previously unknown low abundant species were identified unambiguously. One such structural isomer at low level, terminal GlcNAc of G1F+GlcNAc, was identified to be linked at the 1,6 branch. Additionally, another low level structural isomer, previously assigned as Man8 glycan, was found to be Man7+Glc glycan as its 1,3 branch containing three mannoses and one terminal glucose. The identification was further confirmed by a purified α-1,2-endomannosidase enzyme to generate the cleavage of α-1,3 linked terminal disaccharides (Man+glucose). Using this approach, different lots or different CHO produced mAbs was thoroughly examined and found that the newly identified "Man8" (Man7+Glc) was also present in different batches and in some commercially available therapeutic mAbs.