Single-cell and spatial RNA sequencing reveal the spatiotemporal trajectories of fruit senescence.

The senescence of fruit is a complex physiological process, with various cell types within the pericarp, making it highly challenging to elucidate their individual roles in fruit senescence. In this study, a single-cell expression atlas of the pericarp of pitaya (Hylocereus undatus) is constructed, revealing exocarp and mesocarp cells undergoing the most significant changes during the fruit senescence process. Pseudotime analysis establishes cellular differentiation and gene expression trajectories during senescence. Early-stage oxidative stress imbalance is followed by the activation of resistance in exocarp cells, subsequently senescence-associated proteins accumulate in the mesocarp cells at late-stage senescence. The central role of the early response factor HuCMB1 is unveiled in the senescence regulatory network. This study provides a spatiotemporal perspective for a deeper understanding of the dynamic senescence process in plants.

Application research of radiomics in colorectal cancer: A bibliometric study.

BACKGROUND: Radiomics has shown great potential in the clinical field of colorectal cancer (CRC). However, few bibliometric studies have systematically analyzed existing research in this field. The purpose of this study is to understand the current research status and future development directions of CRC. METHODS: Search the English documents on the application of radiomics in the field of CRC research included in the Web of Science Core Collection from its establishment to October 2023. VOSviewer and CiteSpace software were used to conduct bibliometric and visual analysis of online publications related to countries/regions, authors, journals, references, and keywords in this field. RESULTS: A total of 735 relevant documents published from Web of Science Core Collection to October 2023 were retrieved, and a total of 419 documents were obtained based on the screening criteria, including 376 articles and 43 reviews. The number of publications is increasing year by year. Among them, China publishes the most relevant documents (n = 238), which is much higher than Italy (n = 69) and the United States (n = 63). Tian Jie is the author with the most publications and citations (n = 17, citations = 2128), GE Healthcare is the most productive institution (n = 26), Frontiers in Oncology is the journal with the most publications (n = 60), and European Radiology is the most cited journal (n = 776). Hot spots for the application of radiomics in CRC include magnetic resonance, neoadjuvant chemoradiotherapy, survival, texture analysis, and machine learning. These directions are the current hot spots for the application of radiomics research in CRC and may be the direction of continued development in the future. CONCLUSION: Through bibliometric analysis, the application of radiomics in CRC has been increasing year by year. The application of radiomics improves the accuracy of preoperative diagnosis, prediction, and prognosis of CRC. The results of bibliometrics analysis provide a valuable reference for the research direction of radiomics. However, radiomics still faces many challenges in the future, such as the single nature of the data source which may affect the comprehensiveness of the results. Future studies can further expand the data sources and build a multicenter public database to more comprehensively reflect the research status and development trend of CRC radiomics.

CsMYC2 is involved in the regulation of phenylpropanoid biosynthesis induced by trypsin in cucumber (Cucumis sativus) during storage.

Trypsin has a new activity of scavenging superoxide anion and generating hydrogen peroxide. Trypsin can significantly improve the storage quality of C. sativus. To illustrate the mechanism of trypsin-induced resistance in fruits and vegetables, an integrated analysis of widely targeted metabolomics and transcriptomics was carried out. Transcriptomic results showed that 1068 genes highly related to phenylpropanoid biosynthesis gathered in the brown module were obtained by WGCNA. In KEGG analysis, differentially expressed genes (DEGs) were also highly enriched in EIP (Environmental Information Processing) pathways "Plant hormone signal transduction (map04075)" and "MAPK signaling pathway-plant (map04016)". Next, 87 genes were identified as the leading edge by GSEA analysis. So far, CsMYC2 was highlighted as a key transcription factor that regulates phenylpropanoid biosynthesis identified by GSEA and WGCNA. Furthermore, the major route of biosynthesis of phenylpropanoid compounds including coumarins, lignins, chlorogenic acid, flavonoids, and derivatives regulated by trypsin was also illustrated by both transcriptomic and metabolomic data. Results of O2PLS showed that CsMYC2 was positively correlated with Rosmarinic acid-3-O-glucoside, Epigallocatechin, Quercetin-3-O-sophoroside (Baimaside), and so on. Correlation between CsMYC2, phenylpropanoid related genes, and metabolites in C. sativus was illustrated by co-expression networks. Roles of CsMYC2 were further checked in C. sativus by VIGS. The results of this study might give new insight into the exploration of the postharvest resistance mechanism of C. sativus induced by trypsin and provide useful information for the subsequent mining of resistance genes in C. sativus.

Transcriptome analyses and virus-induced gene silencing identify HuWRKY40 acting as a hub transcription factor in the preservation of Hylocereus undatus by trypsin.

Trypsin can significantly improve the storage quality of Hylocereus undatus (H. undatus). To verify the hub WRKY gene of H. undatus in trypsin preservation, joint analysis of transcriptome and protein-protein interaction (PPI) network was carried out, and virus-induced gene silencing (VIGS) was conducted. In the transcriptome of H. undatus, GO directed acyclic graph (DAG) showed that the GO terms of 55 WRKY genes were mainly enriched in sequence-specific DNA binding, DNA binding transcription factor activity, and so on. The GO enrichment chord diagram showed that HuWRKY40 was significantly up-regulated in the enriched top10 GO terms. KEGG enrichment analysis showed that 55 WRKY genes were mainly enriched in plant-pathogen interaction and MAPK pathway. The results of PPI network showed that HuWRKY40 was a hub protein of WRKY transcription factors (TFs) family regulated by trypsin, which was consistent with the results of transcriptome analysis. Bioinformatics analysis showed that HuWRKY40 of H. undatus had the highest homology with Beta vulgaris L. and Spinacia oleracea L. The function of the core regulatory protein HuWRKY40 was further clarified by VIGS technology. The results of VIGS showed that there was a big difference between the phenotype of the pTRV2-HuWRKY40 group and that of the control group. Finally, it was confirmed that HuWRKY40 accelerated the synthesis of flavonoids and improved the fruit quality during the storage of H. undatus. This study found that trypsin may regulate HuWRKY40 activity through the MAPK cascade pathway, affect the participation of flavonoid synthesis, and then delay fruit corruption. PRACTICAL APPLICATIONS: With attention of people to the safety and freshness of fruits and vegetables, biological preservation technology has become one of the hotspots in the field of preservation in recent years. Trypsin can significantly improve the antioxidant capacity of fruits and vegetables. As a new biological preservative, it is convenient to operate and economical. In the current work, the mechanism of trypsin on the WRKY TFs during H. undatus storage was investigated. The application of trypsin would provide a new strategy for the storage quality control of fruits and vegetables.

EuRBG10 involved in indole alkaloids biosynthesis in Eucommia ulmoides induced by drought and salt stresses.

Alkaloids are natural products with many important medicinal activities. To explore the mechanism of abiotic stress promoting alkaloid biosynthesis in Eucommia ulmoides, transcriptomic analysis and metabonomic analysis were used, virus-induced gene silencing (VIGS) lines of target gene were constructed. The results showed that drought and salt stress caused wilting and blackening of leaves, decreased chlorophyll level, and significantly induced MDA and relative conductivity. To resist the damage of stress to cells, the level of secondary metabolites such as alkaloids increased significantly with the extension of stress time. Transcriptomic results showed that, were. Six alkaloid related genes (AWGs) were gathered in five modules positively correlated with either salt stress or alkaloid contents by WGCNA. Results of GO and KEGG enrichment revealed that biosynthesis of alkaloid, especially indole alkaloid was induced, and degradation of alkaloid was inhibited under salt stress. Combining the results of transcriptome and metabolomics, it was suggested that EuRBG10 promotes the production of indole alkaloids and EuAMO5 inhibits the degradation of alkaloids, which may be the core mechanism of the indole alkaloid biosynthesis pathway (map00901) induced by salt stress. The results of these hub proteins were also consistent with the chordal graph of KEGG enrichment. Hub roles of EuRGB10 was checked in E. ulmoides by VIGS. Our findings provide a preliminary understanding of abiotic stress regulating secondary metabolites such as alkaloids, and propose hub genes that can be used to improve the level of bioactive components in medicinal plant.

Lipid metabolism regulated by superoxide scavenger trypsin in Hylocereus undatus through multi-omics analyses.

To analyze the mechanism of the effect of trypsin on the preservation of Hylocereus undatus, the transcriptomic and widely targeted metabolomic profiles of H. undatus after trypsin treatment were evaluated. Among 477 genes related to lipid metabolism, 32 genes had significant expression differences. GO analysis results showed that the main enriched GO functions include pectinesterase and asparagine esterase activities, and so on. The KEGG metabolic pathway with the highest enrichment rate was fatty acid elongation. The protein-protein interaction (PPI) network analysis results showed that the PPI network of lipid metabolism is a complex biological network of scale-free cells. KCS1, QRT1, and ACC1 acted as hubs to regulate a large number of other proteins and amplify the regulatory role of trypsin to achieve a preservation effect. In addition, three unsaturated fatty acids were upregulated, while eight saturated fatty acids were downregulated. PRACTICAL APPLICATIONS: The postharvest storage of fresh fruits and vegetables brings about bottlenecks to fresh fruits and vegetables. There was also an increasing need for biopreservation techniques. Trypsin could significantly enhance the antioxidant capacity of fruits and vegetables, as a preserver for the storage of fruits and vegetables, which was convenient to operate and more economical. The regulation mechanism of trypsin on lipid metabolism in fruits and vegetables during storage of H. undatus is studied in this paper. The application of trypsin would provide a new strategy for quality control of fruit and vegetable storage.

Omics analyses indicate the routes of lignin related metabolites regulated by trypsin during storage of pitaya (Hylocereus undatus).

The storage quality of Hylocereus undatus was significantly improved by trypsin, a novel preservative. The transcriptomic results revealed that antioxidant signal pathways were induced, while lignin catabolic process was impeded by trypsin. In addition, the results of protein-protein interaction (PPI) network networks suggested that flavone 3'-O-methyltransferase 1 (OMT1), ferulic acid 5-hydroxylase 1 (CYP84A1), cellulose synthase isomer (CEV1), and 4-coumarate-CoA ligase 3 (4CL3) act as hubs of peroxidases, lignin related proteins, and proteins involved in the phenylpropanoid metabolism (PLPs) induced by trypsin. Trypsin also regulated the biosynthesis of lignin, chlorogenic acid, and flavonoids. Caffeic acid might be the hub in the metabolic network of the early pathways of phenylpropanoid biosynthesis. It has been hypothesized that trypsin might quickly induce lignin biosynthesis and then up-regulated bioactive metabolites to enhance storage quality of H. undatus.

Galangin and Kaempferol Alleviate the Indomethacin-Caused Cytotoxicity and Barrier Loss in Rat Intestinal Epithelial (IEC-6) Cells Via Mediating JNK/Src Activation.

Nonsteroidal anti-inflammatory drugs (NSAIDs) like indomethacin and others are widely used in clinics, but they have the potential to cause severe gastrointestinal damage including intestinal barrier dysfunction. Thus, two flavonols galangin and kaempferol with or without heat treatment (100 °C, 30 min) were assessed for their effect on indomethacin-damaged rat intestine epithelial (IEC-6) cells. In total, the cell exposure of 300 µmol/L indomethacin for 24 h caused cell toxicity efficiently, resulting in decreased cell viability, enhanced lactate dehydrogenase (LDH) release or reactive oxygen species (ROS) production, and obvious barrier loss. Meanwhile, pretreatment of the cells with these flavonols for 24 and 48 h before the indomethacin exposure could alleviate cytotoxicity and especially barrier loss, resulting in increased cell viability and transepithelial resistance, decreased LDH release, ROS production, and paracellular permeability, together with the promoted expression of three tight junction proteins zonula occluden-1, occludin, and claudin-1. Moreover, the intracellular Ca2+ concentration and expression levels of p-JNK and p-Src arisen from the indomethacin damage were also reduced by the flavonols, suggesting an inhibited calcium-mediated JNK/Src activation. Consistently, galangin showed higher activity than kaempferol to the cells, while the heated flavonols were less efficient than the unheated counterparts. It is thus highlighted that the two flavonols could alleviate indomethacin cytotoxicity and combat against the indomethacin-induced barrier loss in IEC-6 cells, but heat treatment of the flavonols would weaken the two beneficial functions.

Pretreatment of IEC-6 cells with quercetin and myricetin resists the indomethacin-induced barrier dysfunction via attenuating the calcium-mediated JNK/Src activation.

This study investigated the protective effect of two flavonols quercetin and myricetin on barrier function of rat intestinal epithelial (IEC-6) cells with indomethacin injury. When the cells were pretreated with the heated or unheated flavonols of 2.5-10 µmol/L for 24-48 h and then injured by 300 µmol/L indomethacin for 24 h, they showed reduced lactate dehydrogenase release (LDH) but increased cell viability; however, the flavonols of 20 µmol/L exerted a little effect to increase cell viability or decrease LDH release. Cell pretreatment with 5 µmol/L flavonols also resisted cell barrier dysfunction by increasing transepithelial resistance, reducing paracellular permeability, and promoting mRNA and protein expression of three tight junction proteins zonula occluden-1, occludin, and claudin-1. Although indomethacin injury increased intracellular Ca2+ concentration ([Ca2+]i) and consequently caused JNK/Src activation, the flavonols could decrease [Ca2+]i and attenuate the calcium-mediated JNK/Src activation. Quercetin with less hydroxyl groups was more efficient than myricetin to resist barrier dysfunction, while the unheated flavonols were more active than the heated counterparts to perform this effect. It is thus proposed that quercetin and myricetin could resist barrier dysfunction of the intestine once injured by indomethacin, but heat treatment of flavonols had a negative impact on barrier-protective function of flavonols.

Hub genes and sub-networks of stoma-related genes in Hylocereus undatus through trypsin treatment during storage revealed by transcriptomic analysis.

To further investigate the preservation mechanisms of trypsin, the synergistic mechanisms of trypsin and stoma-related genes were evaluated in Hylocereus undatus. Trypsin significantly induced the stoma closure and improved the storage quality of H. undatus. Transcriptomic analyses of H. undatus revealed that important antioxidant signal pathway, such as SREBP signaling pathway, cellular response to H2 O2 or cellular response to molecule of bacterial origin, were induced; while responses to water deprivation were impeded by trypsin. These results indicated that trypsin relieved pitaya of pressure of water deprivation and exhibited the protection on pitaya during storage. Furthermore, the analyses of networks of protein-protein interaction suggested that OST1, HK5, AT4G27585, and HIR1 act as hubs of stoma-related proteins induced by trypsin during storage of H. undatus. PRACTICAL APPLICATIONS: Preservation of fruit is becoming increasingly important to the world. Keep the balance of production and scavenging of reactive oxygen species is efficient to improve the storage quality of fruit. Trypsin had a novel superoxide anion scavenging activity and protect fruit cells from cellular injury induced by excess ROS. This article investigates the hub genes and interaction mechanisms of stoma closure induced by trypsin during the storage of H. undatus. The application of trypsin provides a new strategy for the quality control of fruit storage. Trypsin will have a broad market and development potential in the area of food additives.

Fast Wetting of a Fullerene Capping Layer Improves the Efficiency and Scalability of Perovskite Solar Cells.

Fullerene derivatives, especially [6,6]-phenyl-C61-butyric acid methyl ester (PCBM), have been widely applied as electron transport layers of inverted planar heterojunction perovskite solar cells (PSCs). However, the solution-processed PCBM capping layer suffers from limited surface wetting which hinders the improvement in efficiency and scalability of PSCs. Herein, we develop a facile hybrid solvent strategy that enables very fast wetting of the PCBM capping layer atop of the perovskite surface, leading to an improved interfacial contact and electron transport. The significantly enhanced wettability of the PCBM solution fulfilled through blending isopropyl alcohol into the commonly used chlorobenzene (CB) is attributed to the reduced surface tension while retaining viscosity. As a result, the electron mobility and electric conductivity of the PCBM capping layer increase by around two times, and the PSC devices exhibit the highest power conversion efficiency (PCE) of 19.92%, which is improved by ∼18% relative to that of the control device (16.78%). Importantly, this strategy is also applicable for other alcohols (ethanol and methanol) and CB blends. Moreover, the fast wetting approach enables us to deposit the PCBM capping layer using a facile drop-casting method, affording comparable PCEs to those obtained by the conventional spin-coating method, which is not achievable by using the conventional single solvent. This fast wetting PCBM capping layer also contributes to efficiency improvement of large-area (1 cm2) devices. These advances hold great potential for other scalable deposition methods such as blade-coating and slot-die coating.

Transcriptomic analysis reveals hub genes and subnetworks related to ROS metabolism in Hylocereus undatus through novel superoxide scavenger trypsin treatment during storage.

BACKGROUND: It was demonstrated in our previous research that trypsin scavenges superoxide anions. In this study, the mechanisms of storage quality improvement by trypsin were evaluated in H. undatus. RESULTS: Trypsin significantly delayed the weight loss and decreased the levels of ROS and membrane lipid peroxidation. Transcriptome profiles of H. undatus treated with trypsin revealed the pathways and regulatory mechanisms of ROS genes that were up- or downregulated following trypsin treatment by gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes pathway (KEGG) enrichment analyses. The current results showed that through the regulation of the expression of hub redox enzymes, especially thioredoxin-related proteins, trypsin can maintain low levels of endogenous active oxygen species, reduce malondialdehyde content and delay fruit aging. In addition, the results of protein-protein interaction networks suggested that the downregulated NAD(P) H and lignin pathways might be the key regulatory mechanisms governed by trypsin. CONCLUSIONS: Trypsin significantly prolonged the storage life of H. undatus through regulatory on the endogenous ROS metabolism. As a new biopreservative, trypsin is highly efficient, safe and economical. Therefore, trypsin possesses technical feasibility for the quality control of fruit storage.

In Situ Investigations of Al/Perovskite Interfacial Structures.

Interfacial properties of perovskite layers and metal electrodes play a crucial role in device performance and long-term stability of perovskite solar cells. In this work, we performed a comprehensive study of the interfacial structures and ion migration at the interface of a CH3NH3PbI3 perovskite layer and an Al electrode using in situ synchrotron radiation photoemission spectroscopy measurements. It was found that the Al electrode can react with the perovskite layers, leading to the formation of aluminum iodide species and the bonding between Al and N, as well as the reduction of Pb2+ ions to metallic Pb species at the interface. Moreover, during the Al deposition, iodide ions can migrate from the CH3NH3PbI3 subsurface to the Al electrode, while the reduced Pb remains at the subsurface. The depth profile photoemission measurements, made by varying the photon energies of incident synchrotron radiation X-rays, demonstrate that the reaction occurs at the Al/CH3NH3PbI3 interface at least with a thickness of ∼3.5 nm below the perovskite surface. This study provides an atomic-level fundamental understanding of the Al/CH3NH3PbI3 interfacial structures and insight into the degradation mechanisms of perovskite solar cells when using Al metal as the electrode.

Successively Regioselective Electrosynthesis and Electron Transport Property of Stable Multiply Functionalized [60]Fullerene Derivatives.

With the recent advance in chemical modification of fullerenes, electrosynthesis has demonstrated increasing importance in regioselective synthesis of novel fullerene derivatives. Herein, we report successively regioselective synthesis of stable tetra- and hexafunctionalized [60]fullerene derivatives. The cycloaddition reaction of the electrochemically generated dianions from [60]fulleroindolines with phthaloyl chloride regioselectively affords 1,2,4,17-functionalized [60]fullerene derivatives with two attached ketone groups and a unique addition pattern, where the heterocycle is rearranged to a [5,6]-junction and the carbocycle is fused to an adjacent [6,6]-junction. This addition pattern is in sharp contrast with that of the previously reported biscycloadducts, where both cycles are appended to [6,6]-junctions. The obtained tetrafunctionalized compounds can be successively manipulated to 1,2,3,4,9,10-functionalized [60]fullerene derivatives with an intriguing "S"-shaped configuration via a novel electrochemical protonation. Importantly, the stability of tetrafunctionalized [60]fullerene products allows them to be applied in planar perovskite solar cells as efficient electron transport layers.

Modifying Mesoporous TiO2 by Ammonium Sulfonate Boosts Performance of Perovskite Solar Cells.

Mesoporous-structure perovskite solar cells (meso-PVKSCs) have been widely utilized due to the achieved high efficiency for which the TiO2 layer usually suffers from sufficient electron trap states, low electron mobility, and inavoidable catalytic activity. Herein, a mesoporous TiO2 (m-TiO2) layer is modified by tetraethylammonium p-toluenesulfonate (abbreviated as TEATS) for the first time, leading to a significant photoelectric conversion efficiency enhancement from 19.14 to 20.69% for Cs0.05MA0.12FA0.83PbI2.55Br0.45 (abbreviated as CsMAFA) meso-PVKSCs. In particular, the obtained champion open-circuit voltage (Voc) is 1.18 V, which is a record high value for meso-PVKSCs with CsMAFA triple cation mixed perovskite. A series of measurements were employed to investigate the influences of TEATS modification on the energy band structures of TiO2 as well as the CsMAFA perovskite layer atop, unveiling that TEATS modification benefits defect passivation of the TiO2 film along with a decrease in the work function of TiO2. Besides, TEATS modification helps to improve the wettability of perovskite precursors on the m-TiO2 substrate, affording improved film quality of perovskite with enhanced crystallinity and grain size. Consequently, the trap states existed in the perovskite film can be passivated, and the interfacial charge recombination is suppressed. This further benefits the improvement of the ambient stability of devices.

Transcriptomic Analysis Reveals Cu/Zn SODs Acting as Hub Genes of SODs in Hylocereus undatus Induced by Trypsin during Storage.

It has been revealed by us that superoxide scavenging is a new activity of trypsin. In this study, the synergistic mechanisms of trypsin and superoxide dismutases (SODs) were evaluated in Hylocereus undatus (pitaya). Trypsin significantly improved the storage quality of H. undatus, including weight loss impediment and decrease of cellular injury. The regulatory mechanisms of 16 SOD genes by trypsin were revealed using transcriptomic analysis on H. undatus. Results revealed that important physiological metabolisms, such as antioxidant activities or metal ion transport were induced, and defense responses were inhibited by trypsin. Furthermore, the results of protein-protein interaction (PPI) networks showed that besides the entire ROS network, the tiny SODs sub-network was also a scale-free network. Cu/Zn SODs acted as the hub that SODs synergized with trypsin during the storage of H. undatus.

Electrochemical Benzylation of [60]Fullerene-Fused Lactones: Unexpected Formation of Ring-Opened Adducts and Their Photovoltaic Performance.

Electrochemical benzylation of [60]fullerene-fused lactones with different motifs unexpectedly affords three types of ring-opened benzylated adducts under different conditions. Both [60]fullerene-fused δ- and γ-lactones can be benzylated to generate ring-opened mono- and bis-benzylated adducts in good yields. In addition, representative fullerene products have been applied as efficient electron-transport materials in perovskite solar cells.

Anchoring Fullerene onto Perovskite Film via Grafting Pyridine toward Enhanced Electron Transport in High-Efficiency Solar Cells.

Fullerene derivatives have been popularly applied as electron transport layers (ETLs) of inverted (p-i-n) planar heterojunction perovskite solar cells (iPSCs) due to their strong electron-accepting abilities, and so far, [6,6]-phenyl-C61-butyric acid methyl ester (PCBM) has been the most commonly used ETL, which suffers, however, from high cost due to the complicated synthetic route. Herein, novel pyridine-functionalized fullerene derivatives (abbreviated as C60-Py) were synthesized facilely via a one-step 1,3-dipolar cycloaddition reaction and applied as ETLs superior to PCBM in iPSC devices. Three pyridine-functionalized fullerene derivatives with different alkyl groups, including methyl, n-butyl, and n-hexyl, grafted onto the pyrrolidine moiety (abbreviated as C60-MPy, C60-BPy, and C60-HPy, respectively) were synthesized. According to cyclic voltammogram study, the chain length of the N-alkyl group has negligible influence on the molecular energy level of C60-Py. However, the ETL performance of C60-Py is sensitively dependent on the chain length of the N-alkyl group, with C60-BPy exhibiting the highest power conversion efficiency (PCE) of 16.83%, which surpasses that based on PCBM ETL (15.87%). The PCE enhancement of C60-BPy device is attributed to the coordination interactions between the pyridine moiety with the Pb2+ ion of CH3NH3PbI3 perovskite, which anchor C60-BPy onto perovskite film and reinforce the passivation of the trap state within the CH3NH3PbI3 perovskite film and suppress the nonradiative electron-hole recombinations, leading to enhanced electron transport reflected by the increase of short-circuit current density ( Jsc). The ambient stability of C60-HPy-based device is much better than that based on PCBM ETL since its long N-alkyl group can function as a superior encapsulating layer protecting the CH3NH3PbI3 layer from contact with the ambient moisture.

Highly efficient electron transport obtained by doping PCBM with graphdiyne in planar-heterojunction perovskite solar cells.

Organic-inorganic perovskite solar cells have recently emerged at the forefront of photovoltaics research. Here, for the first time, graphdiyne (GD), a novel two dimension carbon material, is doped into PCBM layer of perovskite solar cell with an inverted structure (ITO/PEDOT:PSS/CH3NH3PbI(3-x)Cl(x)/PCBM:GD/C60/Al) to improve the electron transport. The optimized PCE of 14.8% was achieved. Also, an average power conversion efficiency (PCE) of PCBM:GD-based devices was observed with 28.7% enhancement (13.9% vs 10.8%) compared to that of pure PCBM-based ones. According to scanning electron microscopy, conductive atomic force microscopy, space charge limited current, and photoluminescence quenching measurements, the enhanced current density and fill factor of PCBM:GD-based devices were ascribed to the better coverage on the perovskite layer, improved electrical conductivity, strong electron mobility, and efficient charge extraction. Small hysteresis and stable power output under working condition (14.4%) have also been demonstrated for PCBM:GD based devices. The enhanced device performances indicated the improvement of film conductivity and interfacial coverage based on GD doping which brought the high PCE of the devices and the data repeatability. In this work, GD demonstrates its great potential for applications in photovoltaic field owing to its networks with delocalized π-systems and unique conductivity advantage.