Work Function Tuning of Carbon Electrode to Boost the Charge Extraction in Hole Transport Layer-Free Perovskite Solar Cells.

Perovskite solar cell (PSC) is a promising photovoltaic technology that achieves over 26% power conversion efficiency (PCE). However, the high materials costs, complicated fabrication process, as well as poor long-term stability, are stumbling blocks for the commercialization of the PSCs in normal structures. The hole transport layer (HTL)-free carbon-based PSCs (C-PSCs) are expected to overcome these challenges. However, C-PSCs have suffered from relatively low PCE due to severe energy loss at the perovskite/carbon interface. Herein, the study proposes to boost the hole extraction capability of carbon electrode by incorporating functional manganese (II III) oxide (Mn3O4). It is found that the work function (WF) of the carbon electrode can be finely tuned with different amounts of Mn3O4 addition, thus the interfacial charge transfer efficiency can be maximized. Besides, the mechanical properties of carbon electrode can also be strengthened. Finally, a PCE of 19.03% is achieved. Moreover, the device retains 90% of its initial PCE after 2000 h of storage. This study offers a feasible strategy for fabricating efficient paintable HTL-free C-PSCs.

Survival comparison of pulmonary neuroendocrine carcinoma, adenocarcinoma with neuroendocrine differentiation, and adenocarcinoma.

Background: Pulmonary adenocarcinoma with neuroendocrine differentiation (ADE_ned) is a relatively uncommon pathological classification, and there exists considerable debate regarding its prognosis and treatment. The purpose of this study was to analyze the survival difference between patients with neuroendocrine carcinoma (NEC), adenocarcinoma (ADE), or ADE_ned and to investigate the prognostic factors influencing the outcomes of individuals diagnosed with pulmonary ADE_ned. Methods: We retrieved information on 316 cases of ADE_ned, 188,823 cases of ADE, and 71,154 cases of NEC diagnosed between 2004 and 2015 from the Surveillance, Epidemiology, and End Results (SEER) database. To account for potential confounding variables, propensity score matching (PSM) was employed. Comparative analyses were conducted to estimate the overall survival (OS) and cancer-specific survival (CSS). Finally, the Cox regression models were used to identify prognostic factors associated with pulmonary ADE_ned. Results: Prior to PSM, patients with lung ADE_ned had a worse OS rate than did those with lung ADE or NEC (5-year OS rate: 13.3% vs. 26.6% vs. 15.6%; P<0.001 and P=0.009, respectively). In terms of CSS, the 5-year CSS rate of patients with ADE_ned was superior to that of NEC but inferior to that of ADE (28.7% vs. 26.8% vs. 43.8%; P=0.006 and P<0.001, respectively). Following PSM, the 5-year survival rate of patients with ADE_ned remained lower than that of individuals with ADE or NEC in terms of OS (13.3% vs. 24.4% vs. 23.0%; P<0.001 and P<0001, respectively) and CSS (28.8% vs. 58.6% vs. 43.1%; P<0.001 and P=0.006, respectively). Finally, the results of the competitive risk regression analysis demonstrated that several variables, including sex, T stage, N stage, M stage, and surgery, were found to be independent prognostic factors for patients diagnosed with pulmonary ADE_ned (all P values <0.05). Conclusions: Patients with lung ADE_ned had a significantly poorer survival outcome compared to those with lung ADE or NEC. Furthermore, sex, tumor-node-metastasis (TNM) stage, and surgery were found to be independent prognostic indicators for cases with lung ADE_ned.

Ternary-Metal Sn-Pb-Zn Perovskite to Reconstruct Top Surface for Efficient and Stable Less-Pb Perovskite Solar Cells.

Though Sn-Pb alloyed perovskite solar cells (PSCs) achieved great progress, there is a dilemma to further increase Sn for less-Pb requirement. High Sn ratio (>70%) perovskite exhibits nonstoichiometric Sn:Pb:I at film surface to aggravate Sn2+ oxidation and interface energy mismatch. Here, ternary metal alloyed (FASnI3 )0.7 (MAPb1- x Znx I3 )0.3 (x = 0-3%) is constructed for Pb% < 30% perovskite. Zn with smaller ionic size and stronger ionic interaction than Sn/Pb assists forming high-quality perovskite film with ZnI6 4- enriched at surface to balance Sn:Pb:I ratio. Differing from uniform bulk doping, surface-rich Zn with lower lying orbits pushes down the energy band of perovskite and adjusts the interface energy for efficient charge transfer. The alloyed PSC realizes efficiency of 19.4% at AM1.5 (one of the highest values reported for Pb% < 30% PSCs). Moreover, stronger bonding of Zn─I and Sn─I contributes to better durability of ternary perovskite than binary perovskite. This work highlights a novel alloy method for efficient and stable less-Pb PSCs.

Low-temperature solution-processed LaNiO3 hole-transport layer for UV-stable inverted perovskite solar cells.

We report a solution-processing method to prepare an inorganic LaNiO3 (LNO) hole-transport layer (HTL) under low temperature (<150 °C) for the first time. The inverted PSCs prepared with LNO exhibit high UV-stability and promising efficiency (17.15%). Our preliminary results show great potential for LNO HTL in the fabrication of efficient and photostable inverted perovskite solar cells (PSCs).

Manipulation of the Buried Interface for Robust Formamidinium-based Sn-Pb Perovskite Solar Cells with NiOx Hole-Transport Layers.

Low band gap tin-lead perovskite solar cells (Sn-Pb PSCs) are expected to achieve higher efficiencies than Pb-PSCs and regarded as key components of tandem PSCs. However, the realization of high efficiency is challenged by the instability of Sn2+ and the imperfections at the charge transfer interfaces. Here, we demonstrate an efficient ideal band gap formamidinium (FA)-based Sn-Pb (FAPb0.5 Sn0.5 I3 ) PSC, by manipulating the buried NiOx /perovskite interface with 4-hydroxyphenethyl ammonium halide (OH-PEAX, X=Cl- , Br- , or I- ) interlayer, which exhibits fascinating functions of reducing the surface defects of the NiOx hole transport layer (HTL), enhancing the perovskite film quality, and improving both the energy level matching and physical contact at the interface. The effects of different halide anions have been elaborated and a 20.53 % efficiency is obtained with OH-PEABr, which is the highest one for FA-based Sn-Pb PSCs using NiOx HTLs. Moreover, the device stability is also boosted.

Regulating the Interplay at the Buried Interface for Efficient and Stable Carbon-Based CsPbI2Br Perovskite Solar Cells.

Buried interface modification is promising for preparing high-performance perovskite solar cells (PSCs) by improving the film quality and adjusting the interfacial energy level alignment. In this work, multifunctional ethylenediaminetetraacetic acid diammonium (EAD)-modulated ZnO is employed as an effective buried interface to regulate the interplay between SnO2 and CsPbI2Br in carbon-based inorganic PSCs (C-IPSCs). The burying of EAD into the ZnO interlayer not only enhances the photoelectric properties of ZnO by passivating oxygen defects but also adjusts the energy level alignment of the buried interface. More importantly, the perovskite quality is optimized and the buried interface defects are passivated due to the formation of coordination and hydrogen bondings. Benefiting from such a robust and efficient charge transfer configuration, a maximum power conversion efficiency of 14.58% is achieved in the optimized device, which represents the highest performance reported among those of low-temperature CsPbI2Br C-IPSCs. In addition, the unencapsulated device demonstrates better long-term and thermal stability.

Small Molecules Functionalized Zinc Oxide Interlayers for High Performance Low-Temperature Carbon-Based CsPbI2 Br Perovskite Solar Cells.

The charge recombination resulting from bulk defects and interfacial energy level mismatch hinders the improvement of the power conversion efficiency (PCE) and stability of carbon-based inorganic perovskite solar cells (C-IPSCs). Herein, a series of small molecules including ethylenediaminetetraacetic acid (EDTA) and its derivatives (EDTA-Na and EDTA-K) are studied to functionalize the zinc oxide (ZnO) interlayers at the SnO2 /CsPbI2 Br buried interface to boost the photovoltaic performance of low-temperature C-IPSCs. This strategy can simultaneously passivate defects in ZnO and perovskite films, adjust interfacial energy level alignment, and release interfacial tensile stress, thereby improving interfacial contact, inhibiting ion migration, alleviating charge recombination, and promoting electron transport. As a result, a maximum PCE of 13.94% with a negligible hysteresis effect is obtained, which is one of the best results reported for low-temperature CsPbI2 Br C-IPSCs so far. Moreover, the optimized devices without encapsulation demonstrate greatly improved operational stability.

Impact of air temperature and containment measures on mitigating the intrahousehold transmission of SARS-CoV-2: a data-based modelling analysis.

OBJECTIVES: Air temperature has been considered a modifiable and contributable variable in COVID-19 transmission. Implementation of non-pharmaceutical interventions (NPIs) has also made an impact on COVID-19 transmission, changing the transmission pattern to intrahousehold transmission under stringent containment measures. Therefore, it is necessary to re-estimate the influence of air temperature on COVID-19 transmission while excluding the influence of NPIs. DESIGN, SETTING AND PARTICIPANTS: This study is a data-based comprehensive modelling analysis. A stochastic epidemiological model, the ScEIQR model (contactable susceptible-exposed-infected-quarantined-removed), was established to evaluate the influence of air temperature and containment measures on the intrahousehold spread of COVID-19. Epidemic data on COVID-19, including daily confirmed cases, number of close contacts, etc, were collected from the National Health Commission of China. OUTCOME MEASURES: The model was fitted using the Metropolis-Hastings algorithm with a cost function based on the least squares method. The LOESS (locally weighted scatterplot smoothing) regression function was used to assess the relationship between air temperature and rate of COVID-19 transmission within the ScEIQR model. RESULTS: The ScEIQR model indicated that the optimal temperature for spread of COVID-19 peaked at 10℃ (50℉), ranging from 5℃ to 14℃ (41℉-57.2℉). In the fitted model, the fitted intrahousehold transmission rate (ß') of COVID-19 was 10.22 (IQR 8.47-12.35) across mainland China. The association between air temperature and ß' of COVID-19 suggests that COVID-19 might be seasonal. Our model also validated the effectiveness of NPIs, demonstrating that diminishing contactable susceptibility (Sc) and avoiding delay in diagnosis and hospitalisation (η) were more effective than contact tracing (κ and ρ). CONCLUSIONS: We constructed a novel epidemic model to estimate the effect of air temperature on COVID-19 transmission beyond implementation of NPIs, which can inform public health strategy and predict the transmission of COVID-19.

FA/MA Cation Exchange for Efficient and Reproducible Tin-Based Perovskite Solar Cells.

Nontoxic tin-based perovskite solar cells (Sn-PSCs) as a promising alternative to toxic Pb-PSCs have drawn great attention in recent years for their environmental friendliness and unique optoelectronic properties. However, both the efficiency and long-term stability of Sn-PSCs are considerably inferior to those of Pb-based ones. One of the main reasons is the difficulty in obtaining high-quality Sn-perovskite films due to the rapid crystallization of Sn-perovskites, which also results in poor device reproducibility. Here, we report a novel cation exchange strategy to prepare high-quality formamidinium tin triiodide (FASnI3) perovskite films with a better controlled crystallization process and improved reproducibility, which allows easy access to smooth and pinhole-free perovskite films with oriented crystal growth, enlarged grain size, and reduced trap-state density. The corresponding Sn-PSCs show excellent photovoltaic performance with a champion efficiency of 9.11%, comparable to the best results reported for FASnI3-PSCs, and the devices also demonstrate outstanding long-term stability without encapsulation. Our results offer a practical strategy for fabricating Sn-PSCs with superb performance and stability.

2D materials for conducting holes from grain boundaries in perovskite solar cells.

Grain boundaries in organic-inorganic halide perovskite solar cells (PSCs) have been found to be detrimental to the photovoltaic performance of devices. Here, we develop a unique approach to overcome this problem by modifying the edges of perovskite grain boundaries with flakes of high-mobility two-dimensional (2D) materials via a convenient solution process. A synergistic effect between the 2D flakes and perovskite grain boundaries is observed for the first time, which can significantly enhance the performance of PSCs. We find that the 2D flakes can conduct holes from the grain boundaries to the hole transport layers in PSCs, thereby making hole channels in the grain boundaries of the devices. Hence, 2D flakes with high carrier mobilities and short distances to grain boundaries can induce a more pronounced performance enhancement of the devices. This work presents a cost-effective strategy for improving the performance of PSCs by using high-mobility 2D materials.

Adjuvant chemotherapy improves the prognosis of early stage resectable pulmonary large cell carcinoma: analysis of SEER data.

BACKGROUND: Pulmonary large cell carcinoma (LCC) is a poorly differentiated and rare tumor with dismal outcome, and there are no recommended treatments for LCC. Little is known about the efficacy of postoperative chemotherapy in patients with early stage LCC. METHODS: The patients with early stage I/II LCC in the Surveillance, Epidemiology and End Results (SEER) database between 2004 and 2015 were retrospectively reviewed. The overall survival (OS) of patients with LCC at different stages and treatments were evaluated by Kaplan-Meier analysis with log-rank test. Univariate and multivariate Cox proportional risk regression analysis were employed to determine the independent risk factors of OS. Finally, a nomogram was constructed to predict the 1 -, 3- and 5-year OS of early stage LCC patients. RESULTS: A total of 1,099 pulmonary LCC cases were included in this study. 71.8% of patients were over 60 years old, and 66.7% of the tumor lesions located in the upper lobe, followed by the lower lobe (25.7%). Meanwhile, the majority of tumors showed poor differentiation (96.1%). The median OS of surgical patients with or without post-operative adjuvant chemotherapy was 61 and 47 months, respectively. Post-operative chemotherapy was associated with better OS (HR: 0.805; 95% CI: 0.676-0.959, P=0.020). For patients with tumor size >3 cm or IB stage tumor, the prognosis of postoperative chemotherapy was better than that of patients without chemotherapy. Multivariate Cox analysis revealed the age, stage and treatments were independent risk factors of OS for early stage LCC. The nomogram had a calibration index of 0.581. CONCLUSIONS: The incidence of LCC was high in the elderly, and it generally had poor differentiation. Post-operative chemotherapy is strongly recommended for patients with LCC at stage IB or higher.

Lead-Free Perovskite/Organic Semiconductor Vertical Heterojunction for Highly Sensitive Photodetectors.

In recent years, photodetectors based on organic-inorganic lead halide perovskites have been studied extensively. However, the inclusion of lead in those materials can cause severe human health and environmental problems, which is undesirable for practical applications. Here, we report high-performance photodetectors with a tin-based perovskite/PEDOT:PSS vertical heterojunction. The device demonstrates a broadband photoresponse from NIR to UV. The maximum responsivity and gain are up to 2.6 × 106 A/W and 4.7 × 106, respectively. Moreover, a much shorter response time and higher detectivity can be achieved by reducing the thickness of PEDOT:PSS. The outstanding performance is due to the excellent optoelectronic properties of the perovskite and the photogating effect originating from the heterojunction. Furthermore, devices fabricated on flexible substrates can demonstrate not only high sensitivity but also excellent bending stability. This work opens up the opportunity of using lead-free perovskite in highly sensitive photodetectors with vertical heterojunctions.

Clinical characteristics and treatments of large cell lung carcinoma: a retrospective study using SEER data.

BACKGROUND: Large cell lung carcinoma (LCLC) is a rare malignancy with poor outcome, and little is known about its clinical characteristics and treatments. METHODS: The clinical information of LCLC patients was collected from the Surveillance, Epidemiology, and End Results (SEER) database between 2004 and 2015. The Kaplan-Meier method was used to determine the overall survival (OS) and lung cancer-specific survival (LCSS). Univariate and multivariate analyses were further performed to investigate the independent prognostic factors of OS. A final nomogram was built using the Cox proportional hazards model. RESULTS: In total, 4,099 patients diagnosed with LCLC were included. 70.2% of patients were older than 60, and more male patients were found. Besides, 60.2% of lesions were found in the upper lobe. Moreover, most patients showed poor differentiation and presented with stage III or IV. Multivariate Cox analysis revealed age, gender, marital status, laterality, tumor size, stage, chemotherapy and surgery were independent prognostic factors of LCLC. The prognosis after surgery combined with chemotherapy was better than that after surgery alone (P=0.041, HR =0.875, 95% CI: 0.771-0.993). The nomogram had good discrimination with a concordance index of 0.757. CONCLUSIONS: LCLC is more common in the elderly and males. Most of lesions are located in the upper lobe and are diagnosed at stage III/IV with poor differentiation. Age, gender, marital status, laterality, tumor size, stage, chemotherapy and surgery were associated with OS. Surgery combined with chemotherapy may achieve a better prognosis and the nomogram accurately predicted the 1-, 3-, and 5-year OS.

Sn-Based Perovskite for Highly Sensitive Photodetectors.

Organic-inorganic hybrid perovskites have emerged as promising functional materials for high-performance photodetectors. However, the toxicity of Pb and the lack of internal gain mechanism in typical perovskites significantly hinder their practical applications. Herein, a low-voltage and high-performance photodetector based on a single layer of lead-free Sn-based perovskite film is reported. The device shows broadband response from ultraviolet to near-infrared light with a responsivity up to 105 A W-1 and a high gain at a low operating voltage. The outstanding performance is attributed to the high hole mobility, p-doping nature, and excellent optoelectronic properties of the Sn-based perovskite. Moreover, the device is assembled on a flexible substrate and demonstrates both high sensitivity and good bending stability. This work demonstrates a route for realizing nontoxic, low-cost, and high-performance perovskite photodetectors with a simple device structure.

Solution-Phase Epitaxial Growth of Perovskite Films on 2D Material Flakes for High-Performance Solar Cells.

The quality of perovskite films is critical to the performance of perovskite solar cells. However, it is challenging to control the crystallinity and orientation of solution-processed perovskite films. Here, solution-phase van der Waals epitaxy growth of MAPbI3 perovskite films on MoS2 flakes is reported. Under transmission electron microscopy, in-plane coupling between the perovskite and the MoS2 crystal lattices is observed, leading to perovskite films with larger grain size, lower trap density, and preferential growth orientation along (110) normal to the MoS2 surface. In perovskite solar cells, when perovskite active layers are grown on MoS2 flakes coated on hole-transport layers, the power conversion efficiency is substantially enhanced for 15%, relatively, due to the increased crystallinity of the perovskite layer and the improved hole extraction and transfer rate at the interface. This work paves a way for preparing high-performance perovskite solar cells and other optoelectronic devices by introducing 2D materials as interfacial layers.

Antioxidant Grain Passivation for Air-Stable Tin-Based Perovskite Solar Cells.

Tin-based perovskites with excellent optoelectronic properties and suitable band gaps are promising candidates for the preparation of efficient lead-free perovskite solar cells (PSCs). However, it is challenging to prepare highly stable and efficient tin-based PSCs because Sn2+ in perovskites can be easily oxidized to Sn4+ upon air exposure. Here we report the fabrication of air-stable FASnI3 solar cells by introducing hydroxybenzene sulfonic acid or its salt as an antioxidant additive into the perovskite precursor solution along with excess SnCl2 . The interaction between the sulfonate group and the Sn2+ ion enables the in situ encapsulation of the perovskite grains with a SnCl2 -additive complex layer, which results in greatly enhanced oxidation stability of the perovskite film. The corresponding PSCs are able to maintain 80 % of the efficiency over 500 h upon air exposure without encapsulation, which is over ten times longer than the best result reported previously. Our results suggest a possible strategy for the future design of efficient and stable tin-based PSCs.

Emerging Semitransparent Solar Cells: Materials and Device Design.

Semitransparent solar cells can provide not only efficient power-generation but also appealing images and show promising applications in building integrated photovoltaics, wearable electronics, photovoltaic vehicles and so forth in the future. Such devices have been successfully realized by incorporating transparent electrodes in new generation low-cost solar cells, including organic solar cells (OSCs), dye-sensitized solar cells (DSCs) and organometal halide perovskite solar cells (PSCs). In this review, the advances in the preparation of semitransparent OSCs, DSCs, and PSCs are summarized, focusing on the top transparent electrode materials and device designs, which are all crucial to the performance of these devices. Techniques for optimizing the efficiency, color and transparency of the devices are addressed in detail. Finally, a summary of the research field and an outlook into the future development in this area are provided.

Three-Dimensional Branched TiO2 Architectures in Controllable Bloom for Advanced Lithium-Ion Batteries.

Three-dimensional branched TiO2 architectures (3D BTA) with controllable morphologies were synthesized via a facile template-free one-pot solvothermal route. The volume ratio of deionized water (DI water) and diethylene glycol in solvothermal process is key to the formation of 3D BTA assembled by nanowire-coated TiO2 dendrites, which combines the advantages of 3D hierarchical structure and 1D nanoscale building blocks. Benefiting from such unique structural features, the BTA in full bloom achieved significantly increased specific surface areas and shortened Li(+) ion/electrons diffusion pathway. The lithium-ion batteries based on BTA in full bloom exhibited remarkably enhanced reversible specific capacity and rate performance, attributing to the high contact area with the electrolyte and the short solid state diffusion pathway for Li(+) ion/electrons promoting lithium insertion and extraction.

Efficient and stable perovskite solar cells prepared in ambient air irrespective of the humidity.

Poor stability of organic-inorganic halide perovskite materials in humid condition has hindered the success of perovskite solar cells in real applications since controlled atmosphere is required for device fabrication and operation, and there is a lack of effective solutions to this problem until now. Here we report the use of lead (II) thiocyanate (Pb(SCN)2) precursor in preparing perovskite solar cells in ambient air. High-quality CH3NH3PbI3-x(SCN)x perovskite films can be readily prepared even when the relative humidity exceeds 70%. Under optimized processing conditions, we obtain devices with an average power conversion efficiency of 13.49% and the maximum efficiency over 15%. In comparison with typical CH3NH3PbI3-based devices, these solar cells without encapsulation show greatly improved stability in humid air, which is attributed to the incorporation of thiocyanate ions in the crystal lattice. The findings pave a way for realizing efficient and stable perovskite solar cells in ambient atmosphere.

Efficient Semitransparent Perovskite Solar Cells with Graphene Electrodes.

Semitransparent perovskite solar cells are prepared by laminating graphene transparent electrodes on the top for the first time. The device performance is optimized by improving the conductivity of the graphene electrodes and the contact between the graphene and the perovskite active layers during the lamination process. The devices show high power conversion efficiencies when they are illuminated from both sides.