High power conversion efficiencies (PCE), low energy payback time (EPBT), and low manufacturing costs render perovskite solar cells (PSCs) competitive; however, a relatively low operational stability impedes their large-scale deployment. In addition, state-of-the-art PSCs are made of expensive materials, including the organic hole transport materials (HTMs) and the noble metals used as the charge collection electrode, which induce degradation in PSCs. Thus, developing inexpensive alternatives is crucial to fostering the transition from academic research to industrial development. Combining a carbon-based electrode with an inorganic HTM has shown the highest potential and should replace noble metals and organic HTMs. In this review, we illustrate the incorporation of a carbon layer as a back contact instead of noble metals and inorganic HTMs instead of organic ones as two cornerstones for achieving optimal stability and economic viability for PSCs. We discuss the primary considerations for the selection of the absorbing layer as well as the electron-transporting layer to be compatible with the champion designs and ultimate architecture for single-junction PSCs. More studies regarding the long-term stability are still required. Using the recommended device architecture presented in this work would pave the way toward constructing low-cost and stable PSCs.

Epitaxial growth technology has garnered widespread attention in the field of perovskite solar cells for its potential to produce high-quality crystals with preferred orientations and superior photoelectric properties. However, achieving rational epitaxial growth in the fabrication process of perovskite solar cells still remains a challenging task. A thorough understanding of the fundamental principles of epitaxial growth and an appreciation of the unique advantages of the main epitaxial strategies are crucial for the effective application of this technique in the realm of metal halide perovskites. Unfortunately, due to the lack of a comprehensive summary of the epitaxial metal halide perovskite solar cells, current researchers have insufficiently explored the application of epitaxial growth methods, leading to a limited understanding of the underlying principles and immature process development. Therefore, this review systematically summarizes the principle of epitaxial growth technologies, the main epitaxial strategies, and the latest research progresses in its application to perovskite solar cells, aiming to assist readers in better understanding and applying this technique in the context of perovskite solar cells.

Graphene oxide (GO)-based nanomaterials have unique physical, chemical, and biological properties that make their use in biomedical research and nanomedicine of enormous interest. However, little is known about their sublethal effects on biological systems, especially mitochondrial damage. Here, by using super-resolution imaging in live cells, we discovered that GO nanosheets damage mitochondrial membranes in a dose-dependent manner in both cancer and healthy cell lines. Furthermore, we observed that GO nanosheets destroy the integrity of mitochondrial cristae. We performed simulations to clarify the mechanisms governing that behavior and found that GO nanosheets insert into membranes, thereby resulting in membrane “cutting” and that the size of GO nanosheets is an essential factor of inducing fragmentation. Those results, demonstrating that large GO nanosheets induce mitochondrial damage, indicate that the assessment and safety profiling of GO-based biomedical research tools and products should include the careful evaluation of their effects on mitochondria.

Peptide-based piezoelectric materials have emerged as a new class of intelligent biomaterials, and applying electric fields during growth was found to result in uniform polarization. Here, we explore in-depth the effect of electric fields on diphenylalanine peptide crystallization and epitaxial growth. The percentage of crystals with negative polarization is linearly proportional to the electric field strength, while the trend is slightly different when a positive electric field is applied. The minimum electric field strength needed to achieve peptides with a uniform polarization is about 200 kV/m. Due to the improved crystallinity and uniform polarization in peptides, the piezoelectric constant d33 increases linearly with the applied electric fields. The output voltage and current of peptide-based piezoelectric nanogenerators increase with the applied force on the device and with the electric field used for growth material, and the power density reaches 9.98 W/m3. Our work provides direct insight into the peptide self-assembly process under electric fields and guides the fabrication of high-performance materials for degradable energy devices.

Molybdenum ditelluride (MoTe2) exhibits a variety of crystal phases, which can be phase-controlled by various external means, showing broad prospects in modern integrated circuits. The structure in which the semimetal 1T′ (or Td) phase electrode contacts the semiconductor 2H phase channel is considered an elegant solution for high-performance two-dimensional (2D) circuits because it achieves low contact resistance. However, most of the 2D metal–semiconductor structures for large-area integration use a two-step growth process, which puts forward high requirements for the secondary growth compatibility of the material. Here, we develop a method for the stable synthesis of the metallic MoxW1–xTe2 (0 < x < 1) by W-triggered spatial phase engineering, and we further obtain a large-area MoxW1–xTe2/2H-MoTe2 in-plane metal–semiconductor structure by one-step tellurization of a MoW/Mo periodic structure. Due to the unique 2D in-plane epitaxial mechanism of the phase transition from 1T′ to 2H, the highly crystalline semiconductor 2H-MoTe2 squeezes between two metallic MoxW1–xTe2 electrodes and forms a seamless coplanar contacted channel; thus, the fabricated field-effect transistors exhibit good electrical characteristics. In addition, large-area 2D metal–semiconductor heterostructure arrays can be transferred onto flexible substrates, showing promising applications in flexible electronics. Herein, one-step synthesis of large-area 2D in-plane metal–semiconductor arrays opens up new possibilities for future integrated high-performance logic circuits.

Photodynamic therapy (PDT) has attracted much attention in recent years due to its high selectivity; however, limited by the heterogeneity of a tumor oxygen environment, the hypoxic region of a tumor will be significantly resistant to PDT. Herein, we report an oxygen level-responsive transformable therapeutic nanomedicine consisting of a hypoxia-responsive molecule (Cy-NO2), a radical generator (ADVN), and a pH-responsive polymer. In the normoxic region, Cy-NO2 in the nanomedicine plays the role of photosensitizer under 808 nm laser irradiation to realize effective PDT, while in hypoxic intracellular conditions, the Cy-NO2 will be converted into a photothermal agent, which can induce the decomposition of ADVN through photothermal effect to generate toxic free radicals for thermodynamic therapy. Therefore, by identifying the environmental characteristics and transforming treatment approaches, this nanomedicine can achieve good therapeutic effects under both normoxic and hypoxic conditions. This work offers a promising strategy for overcoming oxygen heterogeneity to achieve smart cancer therapy.

Thermally activated delayed fluorescence (TADF) organic light-emitting diodes (OLEDs) have attracted public attention due to their high external quantum efficiency (EQE) and implication in future display technology. Despite their improved efficiency, TADF-based OLEDs still suffer from serious efficiency roll-off and short operational lifetimes. Herein, a diboron-based molecule, PhCzDBA, is designed and its device exhibits a maximum EQE (EQEmax) of 33.8% and only slight roll-off (EQEmax of 31.5% at 1000 cd m–2 and 28.8% at 3000 cd m–2). Furthermore, it shows superior stability among reported TADF devices (LT80 of 113 h at the initial luminance of 3000 cd m–2). Remarkably, its nondoped OLED shows a high EQEmax of 17.7% with a λmax > 580 nm, surpassing most orange nondoped OLEDs. Moreover, a decent white OLED device with an EQEmax of 16.4% and a color rendering index (CRI) of 73 can be achieved by incorporating a simple sandwich emitting layer configuration, exhibiting the potential and diverse applications in many aspects.

Incorporating an aggregation-induced emission (AIE) effect into polymers will lead to intriguing solid-state fluorescent materials (i.e., AIE-active polymers) that have great potential in optoelectronics and sensing applications. In this work, a series of AIE-active polyimine vitrimers (TPE-PIs), containing different loadings of tetraphenylethene (TPE) moieties, have been successfully prepared where AIE-active monomers are chemically integrated into the PI network, either as side chains or in the backbone of the polymer network. The studies reveal that TPE-PIs not only inherit the merits of PI vitrimer (i.e., rehealability, malleability, recyclability) but also provide enhanced mechanical (compared to thermoplastic AIE-active polymers) and luminescent properties (compared to pristine AIE-inactive PIs). Larger enhancement could be achieved when TPE moieties are installed in the polymer backbones, in comparison to those installed in the side chains. Furthermore, their photoluminescence intensity could be significantly enhanced in an underwater environment, exhibiting great potential in underwater applications for luminescent sensing and/or light-emitting.

Mixed-anion compounds are promising candidates as visible-light-driven photocatalysts; however, their synthesis is generally difficult compared to that of their ordinary single-anion counterparts such as oxides. This difficulty is often an obstacle in maximizing the performance of mixed-anion photocatalysts. In this work, Pb2Ti2O5.4F1.2 particles having a well-defined octahedral shape were successfully synthesized by a microwave-assisted hydrothermal (MHT) method at 473 K. The MHT-Pb2Ti2O5.4F1.2 exhibited a greater specific surface area and improved hydrophilicity compared with its analogue synthesized by a conventional solid-state reaction (SSR). Compared with the SSR-Pb2Ti2O5.4F1.2, the MHT-Pb2Ti2O5.4F1.2 exhibited 6-fold greater activity toward visible-light H2 evolution from water. A postheating treatment of the MHT-derived material in air at 573 K further improved its activity 3–4 fold. The optimized MHT-Pb2Ti2O5.4F1.2 also achieved a nonsacrificial H2 evolution in the presence of a reversible electron donor.

The complexities of light penetration, short 1O2 life, severe tumor hypoxia, overexpressed reductive glutathione (GSH), and acidic conditions in the tumor microenvironment (TME) limit the success of photobased multimodal combined therapy (MCT) in anticancer. Herein, the mitochondria targeting nanoadapters with multistimulus responsibility are fabricated for the photothermal imaging guided MCT. The obtained Au NCs@MBA-TPP NAPs can be triggered simultaneously by overexpressed H2O2 and GSH in TME, as well as near-infrared (NIR) laser, achieving chemodynamic therapy (CDT), NIR motivated photothermal therapy (PTT) and photodynamic therapy (PDT). Furthermore, the hematosin in Au NCs@MBA-TPP NAPs causes O2-generation and GSH depletion for the enhancement of PDT and CDT with the mitochondria targeting enhanced MCT effectively by the photothermal imaging guide. Hence, our design provides a new strategy for the integration of diagnosis and treatment with TME modulation to potentially improve the MCT in tumor treatment potentially.