Nab-paclitaxel plus platinum versus paclitaxel plus platinum as first-line therapy in patients with metastatic or recurrent cervical cancer.

PURPOSE: This study aimed to assess the efficacy and safety of nanoparticle albumin-bound paclitaxel (nab-paclitaxel) plus platinum versus paclitaxel plus platinum as first-line therapy in patients with metastatic or recurrent cervical cancer. METHODS: Between October 2020 and March 2022, consecutive patients with diagnosed with metastatic or recurrent cervical cancer were retrospectively recruited in our hospital. Fifty-four patients were treated with nab-paclitaxel plus cisplatin or carboplatin. Twenty-four patients were treated with paclitaxel plus cisplatin or carboplatin. A propensity score matching (PSM) analysis was done using a multivariable logistic regression model. The two groups were compared for objective response rate (ORR), progression-free survival (PFS) and overall survival (OS) in the raw and matched dataset. RESULTS: The nab-paclitaxel group showed a higher ORR than the paclitaxel group both in the raw dataset (72.2% vs. 45.8%; P = 0.025) and matched dataset (81.1% vs. 47.6%; P = 0.008). The median PFS was significantly longer in the nab-paclitaxel group than in the paclitaxel group both in the raw and matched dataset (12 vs. 7 months; P < 0.05). The median OS was not reached in the nab-paclitaxel group compared with 15 months in the paclitaxel group, with a trend toward prolongation. The most common toxicity was hematological adverse events, including grade 3-4 neutropenia, grade 3 anemia and thrombocytopenia in both groups and no statistical differences were observed between the groups (all P > 0.05). CONCLUSION: Compared with paclitaxel plus platinum, nab-paclitaxel plus platinum may be an effective and tolerable option as first-line therapy for patients with metastatic or recurrent cervical cancer.

Bithiophene-Functionalized Infrared Two-Photon Absorption Metal Complexes as Single-Molecule Platforms for Synergistic Photodynamic, Photothermal, and Chemotherapy.

A planar conjugated ligand functionalized with bithiophene and its Ru(II), Os(II), and Ir(III) complexes have been constructed as single-molecule platform for synergistic photodynamic, photothermal, and chemotherapy. The complexes have significant two-photon absorption at 808 nm and remarkable singlet oxygen and superoxide anion production in aqueous solution and cells when exposed to 808 nm infrared irradiation. The most potent Ru(II) complex Ru7 enters tumor cells via the rare macropinocytosis, locates in both nuclei and mitochondria, and regulates DNA-related chemotherapeutic mechanisms intranuclearly including DNA topoisomerase and RNA polymerase inhibition and their synergistic effects with photoactivated apoptosis, ferroptosis and DNA cleavage. Ru7 exhibits high efficacy in vivo for malignant melanoma and cisplatin-resistant non-small cell lung cancer tumors, with a 100 % survival rate of mice, low toxicity to normal cells and low residual rate. Such an infrared two-photon activatable metal complex may contribute to a new generation of single-molecule-based integrated diagnosis and treatment platform to address drug resistance in clinical practice and phototherapy for large, deeply located solid tumors.

Thrombospondin-1 promotes mechanical stress-mediated ligamentum flavum hypertrophy through the TGFß1/Smad3 signaling pathway.

Lumbar spinal canal stenosis is primarily caused by ligamentum flavum hypertrophy (LFH), which is a significant pathological factor. Nevertheless, the precise molecular basis for the development of LFH remains uncertain. The current investigation observed a notable increase in thrombospondin-1 (THBS1) expression in LFH through proteomics analysis and single-cell RNA-sequencing analysis of clinical ligamentum flavum specimens. In laboratory experiments, it was demonstrated that THBS1 triggered the activation of Smad3 signaling induced by transforming growth factor ß1 (TGFß1), leading to the subsequent enhancement of COL1A2 and α-SMA, which are fibrosis markers. Furthermore, experiments conducted on a bipedal standing mouse model revealed that THBS1 played a crucial role in the development of LFH. Sestrin2 (SESN2) acted as a stress-responsive protein that suppressed the expression of THBS1, thus averting the progression of fibrosis in ligamentum flavum (LF) cells. To summarize, these results indicate that mechanical overloading causes an increase in THBS1 production, which triggers the TGFß1/Smad3 signaling pathway and ultimately results in the development of LFH. Targeting the suppression of THBS1 expression may present a novel approach for the treatment of LFH.

Visible-Light-Driven Semiconductor-Metal Transition in Electron Gas at the (100) Surface of KTaO3.

Two-dimensional electron gas (2DEG) at the (100) KTaO3(KTO) surface and interfaces has attracted extensive interest because of its abundant physical properties. Here, light illumination-induced semiconductor-metal transition in the 2DEG at the KTO surface was investigated. 2DEG was formed at the surface of KTO by argon ion bombardment. The 2DEG prepared with a shorter bombardment time (300 s) exhibits semiconducting behavior in the range of 20~300 K in the dark. However, it shows a different resistance behavior, namely, a metallic state above ~55 K and a semiconducting state below ~55 K when exposed to visible light (405 nm) with a giant conductivity increase of about eight orders of magnitude at 20 K. The suppression of the semiconducting behavior is found to be more pronounced with increasing light power. After removing the illumination, the resistance cannot recover quickly, exhibiting persistent photoconductivity. More interestingly, the photoresponse of the 2DEG below 50 K was almost independent of the laser wavelength, although the photon energy is lower than the band gap of KTO. The present results provide experimental support for tuning oxide 2DEG by photoexcitation, suggesting promising applications of KTO-based 2DEG in future electronic and optoelectronic devices.

Effect of moxibustion on ureteral stent-related symptoms after ureteroscopic lithotripsy. / 艾灸对URL术后输尿管支架管综合征的影响.

OBJECTIVES: To observe the clinical efficacy of moxibustion combined with western medication on ureteral stent-related symptoms after ureteroscopic lithotripsy (URL). METHODS: One hundred and fifty patients with upper urinary tract calculus implanted with ureteral stents after URL were randomly divided into a moxibustion group (50 cases, 1 case dropped out), a placebo moxibustion group (50 cases, 3 cases dropped out) and a blank control group (50 cases). No intervention was performed in the blank control group. On the basis of oral administration with tamsulosin hydrochloride sustained release capsule (starting from the first day after surgery, once a day, 0.2 mg each time, continuously for 4 weeks), in the moxibustion group, moxibustion was operated at Guanyuan (CV 4) and bilateral Shenshu (BL 23); the sham-moxibustion was delivered at the same acupoints in the placebo moxibustion group, once daily, 6 times a week, for 15 min in each treatment. The duration of treatment was 4 weeks. Before treatment, and after 1, 2 and 4 weeks of treatment, the scores of lower urinary tract symptoms, body pain, general health, work performance and satisfaction of sexual matters were compared among the 3 groups. The tract calculus clearance rate, urinary infection and the oral administration of painkillers were compared after 4 weeks of treatment in the 3 groups. RESULTS: The scores of lower urinary tract symptoms, body pain and general health after 1 week of treatment, and the scores of lower urinary tract symptoms, body pain, general health and work performance after 2 and 4 weeks of treatment were lower than those before treatment in the 3 groups (P<0.01). The scores of lower urinary tract symptoms and body pain in the moxibustion group after 1, 2 and 4 weeks of treatment were lower than those in the blank control group and the placebo moxibustion group (P<0.01, P<0.05) respectively. The score of general health in the moxibustion group was lower than that in the blank control group after 1 week of treatment (P<0.01), and lower than those of the blank control group and the placebo moxibustion group after 2 and 4 weeks of treatment (P<0.01, P<0.05). Regarding the score of work performance, it was lower in the moxibustion group after 1 and 2 weeks of treatment compared with those in the blank control group (P<0.05, P<0.01), and lower than those of the blank control group and the placebo moxibustion group after 4 weeks of treatment (P<0.01, P<0.05). The tract calculus clearance rate in the moxibustion group was 95.9% (47/49), higher than that in the blank control group (80.0%, 40/50, P<0.05). The proportion of oral administration of painkillers in the moxibustion group (28.6%, 14/49) and the placebo moxibustion group (40.4%, 19/47) was lower than that in the blank control group (76.0%, 38/50, P<0.01) respectively. CONCLUSIONS: Moxibustion combined with western medication relieves lower urinary tract symptoms and body pain, and accelerate the recovery of general health and work performance in the patients after URL.

[Measures for waste and by-product recycling and circular economy of whole industry chain of traditional Chinese medicine resources facing carbon peak and carbon neutrality (dual carbon) goals].

It has become a common consensus that resource conservation and intensive recycling for improving resource utilization efficiency is an important way to achieve carbon peak and carbon neutrality(dual carbon). Traditonal Chinese medicine(TCM)resources as national strategic resources are the material basis and fundamental guarantee for the development of TCM industry and health services. However, the rapid growth of China's TCM industry and the continuous expansion and extension of the industrial chain have exposed the low efficiency of TCM resources. Resource waste and environmental pollution caused by the treatment and discharge of TCM waste have emerged as major problems faced by the development of the industry, which has aroused wide concern. Considering the dual carbon goals, this paper expounds the role and potential of TCM resource recycling and circular economy industry development. Taking the typical model of TCM resource recycling as the case of circular economy industry in reducing carbon source and increasing carbon sink, this paper puts forward the suggestions for the TCM circular economy industry serving the double carbon goals. The suggestions mainly include strengthening the policy and strategic leading role of the double carbon goals, building an objective evaluation system of low-carbon emission reduction in the whole industrial chain of TCM resources, building an industrial demonstration park for the recycling of TCM resources, and promoting the establishment of a circular economy system of the whole industrial chain of TCM resources. These measures are expected to guide the green transformation of TCM resource industry from linear economic model to circular economy model, provide support for improving the utilization efficiency and sustainable development of TCM resources, and facilitate the low-carbon and efficient development of TCM resource industry and the achievement of the double carbon goals.

[Effects of Combined Stress of Polyethylene and Sulfamethazine on Seed Germination, Seedling Growth, and Physiological Characteristics of Soybean].

The combined pollution of antibiotics adsorption by microplastics has become inevitable in soil ecosystems; moreover, the plant biological effects under combined stress remain unclear. This study used soybean variety Jindou 21 as the material and conducted seed germination test and soil-potted seedling experiment to study the effects of different single and combined treatments of polyethylene (PE) and sulfamethazine (SMZ) on seed germination, seedling growth, photosynthetic parameters, chlorophyll fluorescence parameters, and nitrogen metabolism. The results showed that single PE treatment at low levels promoted soybean seed germination and seedling growth physiology; however, inhibited them at a high level. A lower-level PE treatment[10 mg·L-1 (or mg·kg-1)] could promote soybean seed germination, seedling growth, photosynthesis, and nitrogen metabolism, whereas a higher level PE treatment[100 mg·L-1 and 200 mg·L-1 (or mg·kg-1)] had significant inhibition. The single SMZ treatment had different degrees of inhibition on soybean seed germination and seedling growth physiology, and the inhibition degree increased with the increase in SMZ treatment level. Under the different levels of combined treatments of PE and SMZ, adding the lower level PE treatment could alleviate the inhibition of the single SMZ treatment on soybean, with 10 mg·L-1(or mg·kg-1) PE+1 mg·L-1(or mg·kg-1) SMZ treatment having the best comprehensive mitigation effect, which could increase soybean seed germination potential, germination rate, germination index, vigor index, plant height, root length, shoot and root fresh weight, Pn, Gs, Tr, chlorophyll contents, Fv/Fm, ΦPSⅡ, ETR, qP, and key enzyme activities for nitrogen metabolism such as NR and decrease the average germination time, Ci, NPQ, and NO3--N and NH4+-N contents compared with those in the single SMZ treatment. Adding the higher level PE treatment enhanced the inhibition of SMZ on soybean, and the inhibition degree increased with the increase in SMZ treatment level, in which 200 mg·L-1(or mg·kg-1) PE+50 mg·L-1(or mg·kg-1) SMZ treatment yielded the greatest inhibition. In summary, the lower level PE treatment could alleviate the inhibition of SMZ on soybean seeds and seedlings to a certain extent; however, the higher level PE treatment could produce a synergistic effect with SMZ, thus aggravating the toxic effect of the single stress treatment.

Observation of Electric Hysteresis, Polarization Oscillation, and Pyroelectricity in Nonferroelectric p-n Heterojunctions.

The switchable electric polarization is usually achieved in ferroelectric materials with noncentrosymmetric structures, which opens exciting opportunities for information storage and neuromorphic computing. In another polar system of p-n junction, there exists the electric polarization at the interface due to the Fermi level misalignment. However, the resultant built-in electric field is unavailable to manipulate, thus attracting less attention for memory devices. Here, we report the interfacial polarization hysteresis (IPH) in the vertical sidewall van der Waals heterojunctions of black phosphorus and quasi-two-dimensional electron gas on SrTiO_{3}. A nonvolatile switching of electric polarization can be achieved by reconstructing the space charge region (SCR) with long-lifetime nonequilibrium carriers. The resulting electric-field controllable IPH is experimentally verified by electric hysteresis, polarization oscillation, and pyroelectric effect. Further studies confirm the transition temperature of 340 K, beyond which the IPH vanishes. The second transition is revealed with the temperature dropping below 230 K, corresponding to the sharp improvement of IPH and the freezing of SCR reconstruction. This work offers new possibilities for exploring the memory phenomena in nonferroelectric p-n heterojunctions.

Dinuclear osmium complexes as mitochondrion-targeting antitumor photothermal agents in vivo.

Four dinuclear osmium complexes have been constructed for antitumor phototherapy. The most potent Os4 has extremely high photothermal conversion capability under irradiation of an 808 nm low-power laser, targets mitochondria in human melanoma cells without nucleus affinity, and acts as an antitumor photothermal therapy agent in vitro and in vivo.

Molecular-Shape-Controlled Binary to Ternary Resistive Random-Access Memory Switching of N-Containing Heteroaromatic Semiconductors.

In organic resistive random-access memory (ReRAM) devices, deeply understanding how to control the performance of π-conjugated semiconductors through molecular-shape-engineering is important and highly desirable. Herein, we design a family of N-containing heteroaromatic semiconductors with molecular shapes moving from mono-branched 1Q to di-branched 2Q and tri-branched 3Q. We find that this molecular-shape engineering can induce reliable binary to ternary ReRAM switching, affording a highly enhanced device yield that satisfies the practical requirement. The density functional theory calculation and experimental evidence suggest that the increased multiple paired electroactive nitrogen sites from mono-branched 1Q to tri-branched 3Q are responsible for the multilevel resistance switching, offering stable bidentate coordination with the active metal atoms. This study sheds light on the prospect of N-containing heteroaromatic semiconductors for promising ultrahigh-density data-storage ReRAM application.

Giant bipolar unidirectional photomagnetoresistance.

Positive magnetoresistance (PMR) and negative magnetoresistance (NMR) describe two opposite responses of resistance induced by a magnetic field. Materials with giant PMR are usually distinct from those with giant NMR due to different physical natures. Here, we report the unusual photomagnetoresistance in the van der Waals heterojunctions of WSe2/quasi-two-dimensional electron gas, showing the coexistence of giant PMR and giant NMR. The PMR and NMR reach 1,007.5% at -9 T and -93.5% at 2.2 T in a single device, respectively. The magnetoresistance spans over two orders of magnitude on inversion of field direction, implying a giant unidirectional magnetoresistance (UMR). By adjusting the thickness of the WSe2 layer, we achieve the maxima of PMR and NMR, which are 4,900,000% and -99.8%, respectively. The unique magnetooptical transport shows the unity of giant UMR, PMR, and NMR, referred to as giant bipolar unidirectional photomagnetoresistance. These features originate from strong out-of-plane spin splitting, magnetic field-enhanced recombination of photocarriers, and the Zeeman effect through our experimental and theoretical investigations. This work offers directions for high-performance light-tunable spintronic devices.NMR).

Emergent multiferroism with magnetodielectric coupling in EuTiO3 created by a negative pressure control of strong spin-phonon coupling.

Negative pressure has emerged as a powerful tool to tailor the physical properties of functional materials. However, a negative pressure control of spin-phonon coupling for engineering magnetism and multiferroicity has not been explored to date. Here, using uniform three-dimensional strain-induced negative pressure in nanocomposite films of (EuTiO3)0.5:(MgO)0.5, we demonstrate an emergent multiferroicity with magnetodielectric coupling in EuTiO3, matching exactly with density functional theory calculations. Density functional theory calculations are further used to explore the underlying physics of antiferromagnetic-paraelectric to ferromagnetic-ferroelectric phase transitions, the spin-phonon coupling, and its correlation with negative pressures. The observation of magnetodielectric coupling in the EuTiO3 reveals that an enhanced spin-phonon coupling originates from a negative pressure induced by uniform three-dimensional strain. Our work provides a route to creating multiferroicity and magnetoelectric coupling in single-phase oxides using a negative pressure approach.

Correlation of mismatch repair deficiency with clinicopathological features and programmed death-ligand 1 expression in thyroid carcinoma.

BACKGROUND: Mutations in DNA mismatch repair (MMR) genes associated with thyroid carcinoma (TC) have rarely been reported, especially in East Asian populations. METHODS: We examined tumor tissue from a cohort of 241 patients diagnosed with TC between 2008 and 2020. MMR proteins were detected using tissue microarray-based immunohistochemistry in order to identify MMR-protein-deficient (MMR-D) and MMR-protein-intact (MMR-I) tumors. We retrospectively summarized the clinicopathologic characteristics of patients with MMR-D TC, measured the expression of PD-L1, and recorded overall survival (OS) and other clinical outcomes. RESULTS: In our cohort, there were 18 (7.5%) MMR-D (MLH1, MSH2, MSH6, and PMS2) patients, including 12 with papillary TC (PTC) (6.7%), 2 with poorly differentiated TC (PDTC) (4.7%), and 4 with anaplastic TC (ATC) (22.2%). Half of them (9/18) showed a specific deletion in MSH6, and 6 of them also carried variants in the MSH6 and PMS2 gene. Survival was significantly better in patients with MMR-D ATC than in those with MMR-I tumors (p = 0.033). Four of the 18 MMR-D patients (22%) were found to be PD-L1 positive. Their OS was much shorter than that of PD-L1-negative patients. CONCLUSIONS: MMR-D and PD-L1 positivity appear to be associated with clinicopathological characteristics and prognosis in TC. The results indicate that MMR status may have important prognostic significance in TC. Therefore, immune checkpoint inhibitors that target the PD-1/PD-L1 pathway may be a treatment option for TCs.

Black Phosphorus Quantum Dot-Engineered Tin Oxide Electron Transport Layer for Highly Stable Perovskite Solar Cells with Negligible Hysteresis.

An effective combination of smart materials plays an important role in charge transfer and separation for high photoelectric conversion efficiency (PCE) and stable solar cells. Black phosphorus quantum dots (BPQDs) have been revealed as a direct band gap semiconductor with ultrahigh conductivity, which have been explored in the present work as an additive component to a precursor solution of SnO2 nanoparticles that can effectively improve the performance of SnO2 electron transport layer (ETL)-based perovskite solar cells. Such a device can yield a high PCE of 21% with the SnO2/BPQDs mixed ETL, which is higher than those of perovskite solar cells based on SnO2 single layer (18.2%), BPQDs/SnO2 bilayer (19.5%), and SnO2/BPQDs bilayer (20.5%) samples. The mixed samples still possess good stability of more than 90% efficiency after 1000 h under AM 1.5G lamp irradiation and negligible hysteresis. It is found that the strong interaction of BPQDs with SnO2 can not only modify the defects inherent to the SnO2 layer but also inhibit the oxidation of BPQDs. This work provides a promising functional material for SnO2 ETL-based perovskite solar cells and proves that the BPQD-based modification strategy is useful for designing other solar cells with high performance.

Vacuum Based Gas Sensing Material Characterization System for Precise and Simultaneous Measurement of Optical and Electrical Responses.

Gas sensing performance characterization systems are essential for the research and development of gas sensing materials and devices. Although existing systems are almost completely automatically operated, the accuracies of gas concentration control and of pressure control and the ability to simultaneously detect different sensor signals still require improvement. In this study, a high-precision gas sensing material characterization system is developed based on vacuum technology, with the objective of enabling the precise and simultaneous measurement of electrical responses. Because of the implementation of vacuum technology, the gas concentration control accuracy is improved more than 1600 times, whereas the pressure of the test ambient condition can be precisely adjusted between vacuum and 1.2 bar. The vacuum-assisted gas-exchanging mechanism also enables the sensor response time to be determined more accurately. The system is capable of performing sensitivity, selectivity, and stability tests and can control the ambient relative humidity in a precise manner. More importantly, the levels of performance of three different optical signal measurement set-ups were investigated and compared in terms of detection range, linearity, noise, and response time, based on which of their scopes of application were proposed. Finally, single-period and cyclical tests were performed to examine the ability of the system to detect optical and electrical responses simultaneously, both at a single wavelength and in a spectral region.

Nanofiber Architecture Engineering Implemented by Electrophoretic-Induced Self-Assembly Deposition Technology for Flash-Type Memristors.

Electrophoretic deposition (EPD) has been recognized as a promising large-scale film preparation technology for industrial application. Inspired by the conventional EPD method and the crystal diffusion growth strategy, we propose a modified electrophoretic-induced self-assembly deposition (EPAD) technique to control the morphologies of organic functional materials. Here, an ionic-type dye with a conjugated skeleton and strong noncovalent interactions, celestine blue (CB), is chosen as a module molecule for EPAD investigation. As expected, CB molecules can assemble into different nanostructures, dominated by applied voltage, concentration effect, and duration. Compared to a nanopillar layered packing structure formed by the traditional spin-coating method, the EPAD approach can produce a nanofiber structure under a fixed condition of 10 V/10 min. Intriguingly, a memristor device based on a pillar-like nanostructure exhibits WORM-type behavior, while a device based on nanofibers presents Flash memory performance. The assemble process and the memory mechanism are uncovered by molecular dynamics simulations and density-functional theory (DFT) calculations. This work endows the typical EPD technique with a fresh application scenario, where an in-depth study on the growth mechanism of nanofibers and the positive effect of unique morphologies on memristor performance are offered.

Effect of surgical starting time and season on prognosis in octogenarians with colorectal cancer: a retrospective study.

Aim: To investigate the effect of surgical starting time and season on the prognosis of octogenarians with colorectal cancer. Patients & methods: A total of 291 patients aged 80 years or above who received elective colectomy for colorectal cancer between January 2007 and December 2018 in the National Cancer Center in China were included. Results: No significant time- or season-dependent difference in overall survival for all clinical stages was found in the study. Comparing perioperative outcomes, the morning group had a longer operative time than the afternoon group (p = 0.03), but no significant difference was found based on the season of colectomy. Conclusion: These findings provide insights into clinical outcomes for colorectal cancer patients aged more than 80 years.

Recurrent studies have demonstrated that in heart surgery, different surgical starting times can affect the patients' outcomes, mainly due to the 24-h cyclic variations in heart function. This variability also exists in bowel function. The surgical outcomes of elderly patients aged over 80 years are more susceptible to external factors due to their frailty, so we wanted to compare the differences in prognosis of elderly patients who underwent surgery at different times and seasons.

Ocular manifestations of multiple sclerosis in patients from three countries: A Web-based survey.

OBJECTIVE: This study evaluates the epidemiological characteristics, ophthalmological manifestations, and different therapeutic options available for patients with multiple sclerosis (MS) in China, Spain, and Cuba. METHODS: A self-designed questionnaire was used to conduct a comparable descriptive cross-sectional study on patients with MS. The survey included patients' demographic data, ocular manifestations related to MS, and treatment methodology followed in the three countries. The online survey was designed using the Wenjuanxing survey platform, and a survey link was circulated through WhatsApp, WeChat, and emails. Quantitative data were expressed as mean and standard deviation, the Kruskal-Wallis test was used for non-parametric variables. Qualitative data were expressed as numerical and percentage. The chi-square test (χ2) was used to compare the group's response categories. The statistical difference was considered significant when p < 0.05. RESULTS: The female-to-male ratio in all the three countries was 2-3:1, and relapsing-remitting MS (RRMS) was the most frequent in all three countries. Vision loss was slow and progressive in half of the patients from the three countries, with no significant differences (p = 0.524). A higher percentage of steroid treatment was observed in Chinese patients in comparison with the patients from other two countries (p < 0.001), and a similar trend was seen in the use of traditional medicines. Almost one-third of patients who did not receive any treatment recovered spontaneously in all the three countries (p = 0.097). CONCLUSIONS: MS occurs more frequently in the relapsing-remitting clinical form and there is a clear female predominance. The first ocular crisis or clinical debut of MS is characterized by slow and progressive visual impairment, increasing and adding to other ocular manifestations during its evolutionary course. Spontaneous recovery of vision after an attack of optic neuritis in the course of MS is possible.

Coexistence of Photoelectric Conversion and Storage in van der Waals Heterojunctions.

Van der Waals (vdW) heterojunctions, based on two-dimensional (2D) materials, have great potential for the development of ecofriendly and high-efficiency nanodevices, which shows valuable applications as photovoltaic cells, photodetectors, etc. However, the coexistence of photoelectric conversion and storage in a single device has not been achieved until now. Here, we demonstrate a simple strategy to construct a vdW p-n junction between a WSe_{2} layer and quasi-2D electron gas. After an optical illumination, the device stores the light-generated carriers for up to seven days, and then releases a very large photocurrent of 2.9 mA with bias voltage applied in darkness; this is referred to as chargeable photoconductivity (CPC), which completely differs from any previously observed photoelectric phenomenon. In normal photoconductivity, the recombination of electron-hole pairs occurs at the end of their lifetime; in contrast, infinite-lifetime photocarriers can be generated and stored in CPC devices without recombination. The photoelectric conversion and storage are completely self-excited during the charging process. The ratio between currents in full- and empty-photocarrier states below the critical temperature reaches as high as 10^{9}, with an external quantum efficiency of 93.8% during optical charging. A theoretical model developed to explain the mechanism of this effect is in good agreement with the experimental data. This work paves a path toward the high-efficiency devices for photoelectric conversion and storage.