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In this work, cesium salts with functional anions of acetate (Ac−), fluoride (F−) and trifluoroacetate (TFA−) are explored to modulate the deposition of ZnO films in low-temperature carbon-based CsPbI2Br perovskite solar cells.

Pb–O bonds formed by O2 before annealing which block the phase transition of CsPbI2Br from α to δ-phase. Moisture can promote the formation of Pb–O bonds, which enhance the phase stability of CsPbI2Br in ambient conditions.

Hydrophobic organic ammonium halide salts are used to passivate perovskite defects, adjust interfacial energy level alignments, and ultimately improve the efficiency and stability of low-temperature carbon-based CsPbI2Br perovskite solar cells.

We report a solution-processed method to prepare inorganic LaNiO3 (LNO) hole-transport layer (HTL) under low temperature (

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 SnO

Carbon-based perovskite solar cells are competitive candidate for photovoltaic applications in future due to their high-performance, low-cost and good stability. However, the hole transport materials are limited and their properties are not satisfying in carbon-based perovskite solar cells. Here, we report a typical p-type P3HT as hole transport layer for all low-temperature processed carbon-based perovskite solar cells with ZnO electron transport layer. Because P3HT has energy level matching with perovskite film and can facilitate the hole collection process, the power conversion efficiency of device can reach 16.05% that far higher than devices without P3HT hole transport layer. More importantly, due to good hydrophobicity and encapsulation function of P3HT, the stability of devices can also be significantly improved. The power conversion efficiency of device is able to retain over 90% of their initial value over 1200 h upon ambient air exposure without encapsulation. This present study provides a simple strategy for fabricating low-cost, highly efficient and stable perovskite solar cells.

Tin-based perovskites are promising candidates for preparing lead-free perovskite solar cells due to the optimal bandgap and excellent optoelectronic properties, while the low formation energy of Sn2+ vacancy and facile oxidation of Sn2+ to Sn4+ lead to low efficiency and poor air instability of tin-based PSCs. Here, zinc acetate (ZnAc2) is employed as an additive to form a FAI·SnI2·ZnAc2 intermediate phase in the as-deposited films and control the crystallization process. Besides, the presence of Zn ions could favor the crystal growth by modifying the nucleation process. These synergistic effects lead to high-quality tin-based perovskite films with a large grain size and a low density of Sn2+ vacancies. Moreover, ZnAc2 could form a complex with SnCl2 and an antioxidant to uniformly encapsulate the grains and further improve the air stability of the perovskite layers. As a result, the efficiency of tin-based perovskite solar cells is improved from 6.70% to 8.38%. This work demonstrates a viable strategy to fabricate highly efficient and air-stable Sn PSCs by simultaneously suppressing the formation of Sn2+ vacancy and oxidation of Sn2+ in perovskite films.

Maintaining the stability of tin halide perovskites is a major challenge in developing lead-free perovskite solar cells (PSCs). Adding extra SnX2 (X = F, Cl, or Br) in the precursor solution to inh...

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.

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.

As a promising lead-free perovskite candidate, tin-based halide perovskites such as FASnI3 have attracted extensive attention recently in photovoltaic applications. However, the relatively low efficiency and poor long-term stability of tin-based perovskite solar cells hinder their practical applications. Here, ammonium hypophosphite is introduced into the FASnI3 perovskite precursor to suppress the oxidation of Sn2+ and assist the growth of perovskite grains, leading to improved perovskite film quality and reduced defect density, and consequently, the device efficiency and open circuit voltage are substantially improved. More importantly, the solar cells exhibit pronounced enhancement of the long-term stability. This work provides a facile approach for improving the performance of tin-based perovskite solar cells by introducing ammonium hypophosphite as an antioxidant agent in the precursor solution.

The power conversion efficiency of organic–inorganic hybrid perovskite solar cells (PSCs) has been boosted to be comparable with that of commercial silicon solar cells. Although the fabrication cost of solution-processing PSCs can be lower than that of silicon solar cells, PSCs are still facing the big challenge of instability in air due to the presence of organic components in the perovskites. To obtain stable PSCs, fully replacing the A-site organic cations with pure inorganic cations is one of the promising methods. To date, many researchers have studied the inorganic PSCs with astonishing breakthroughs, and the PCE of inorganic lead-based PSCs has exceeded 17%. In this review, the recent progress of inorganic PSCs is summarized and discussed for different perovskite compositions. The challenges of inorganic PSCs are revealed, followed by the outlook of this field.

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.

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.

ObjectivesAir 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 participantsThis 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 measuresThe 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.ResultsThe 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 (β’) of COVID-19 was 10.22 (IQR 8.47–12.35) across mainland China. The association between air temperature and β’ 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).ConclusionsWe 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.

Early non-pharmaceutical interventions (NPIs) are crucial to prevent and control of COVID-19 pandemic. We established a stochastic non-classical SEIR NPIs model (ScEIQRsh) which can quantify the three kinds of NPIs measures simultaneously to mimic the clustered intra-family or intra-acquaintance spreading pattern of COVID-19 under the effective integrated NPIs in Mainland China. Model simulation demonstrated that measures to diminish contactable susceptible (Sc), such as home confinement, travel constraint, social distancing etc. and measures to avoid delay of diagnosis and hospitalized isolation (η) were more effective but consumptive than contact tracing (κ, ρ). From fitted model by MCMC method, the proportion of asymptomatic infectors was 14.88% (IQR 8.17%, 25.37%). The association between air temperature and the fitted transmission rate (β) of COVID-19 suggests that COVID-19 pandemic would be seasonal with the optimal temperature range of 5°C-14°C and peak of 10°C for spreading, and vaccine is indispensable to ultimate prevention COVID-19.

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.

The preparation of high-quality perovskite films with low defect density and long carrier lifetime is a precondition for achieving high-efficiency perovskite solar cells (PSCs). In this work, we successfully incorporated Y3+ ions into perovskite films to enhance the photovoltaic performance of hole-transport-layer-free (HTL-free) carbon-based MAPbBr3 PSCs in ambient atmosphere. The perovskite films exhibit better crystallinity, lower trap density, and longer carrier lifetime after the introduction of Y3+ ions. By optimizing the doping dosage, a maximal power conversion efficiency (PCE) of 8.313% (open-circuit voltage (VOC) = 1.562 V) is achieved for MAPb0.98Y0.02Br3 PSCs. Moreover, the unencapsulated device also shows remarkable long-term stability over 80 days under dry condition with 20–30% relative humidity (RH) at 20–25 °C, which even maintains 95% of its initial PCE when stored in harsh environment (80 °C and 40–70% RH) over 72 h.

The urchin-like polyaniline (i.e. PANI) microsphere was polymerized using the sulfonated polystyrene microsphere (i.e. SPS) as template, and its structure was successfully conformed by the X-ray photoelectron spectrum, Raman spectrum, Ultraviolet-visible spectrum, and TGA thermogram. The urchin-like PANI microspheres with uniform diameter (1.5 μm) can be observed on scanning electron microscopy (SEM). Cyclic voltammetry and galvanostatic charge/discharge tests were carried out to investigate the electrochemical properties of as-prepared urchin-like PANI microspheres. It showed that the specific capacitance (SC) was 435 Fg −1 at a scan rate of 10 mV s −1 , and also exhibited good capability and cycling stability with capacitance retentions of 93% after 1000 cycles, which is superior or close to some individual PANI nanostructures and PANI composite materials. This facile approach is feasible and easy to fabricate microstructural conducting polymer for supercapacitor electrode materials.

We have demonstrate a facile strategy to achieve the controllable morphology transformation of TiO2 induced by the introduction of multi-walled carbon nanotubes. The intervention of functionalized carbon nanotubes (CNTs) is key to the formation of TiO2 nanopompons. Furthermore, the size of the obtained TiO2 nanopompons can be controlled by modulating the CNT amounts. The obtained TiO2 nanopompon-embedded CNT hybrid networks (TNP@CNT HNs) incorporate the advantages of hierarchical nanostructures and 3D interconnected conductive networks, including high surface area, uniform particle/pore size, short Li+ ion/electron transport pathway, and high electronic conductivity. These TNP@CNT HN-based anodes achieve a significant improvement in the insertion/extraction of Li+ ions and electrochemical performances via optimizing the CNT amounts and the size of the TiO2 nanopompons. The lithium-ion batteries based on the optimized TNP@CNT HNs exhibit excellent cycling stability (keeping approximately 200 mA h g−1 after 500 cycles at 2C rate, 1C = 170 mA g−1) and rate performance (approximately 125 mA h g−1 at 20C rate with a capacity retention of 77% after 2000 cycles).

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.

The development of tin-based perovskite solar cells (PSCs) is a promising approach to meet the demand of eco-friendly, lead-free perovskite photovoltaics. Limited to the poor chemical stability of tin perovskites, tin-based PSCs usually have to be fabricated with an inverted device structure and both the device efficiency and stability are highly dependent on the selection of hole transport materials (HTMs). Here, we report the synthesis of inorganic nickel oxide (NiO x ) nanoparticles (NPs) via a soft base precipitation method, which enables us to obtain highly dispersed NiO x NPs over a wide pH window. The as-prepared NiO x NPs are employed as the HTM for formamidinium tin iodide (FASnI3) PSCs, resulting in excellent device efficiency (∼8%) and stability (1200 h). Our study offers a facile strategy for mass production of NiO x NPs and easy access to efficient and robust inorganic HTMs that could further boost the development of high performance tin-based PSCs.

Carbon electrode-based hole transport layer-free perovskite solar cells (C–PSCs) are widely recognized as a competitive candidate towards practical applications, due to their advantages of low-cost, easy-fabrication, and long-term stability. However, fully low-temperature preparation of this type of solar cells on flexible substrates remains a huge challenge. Here, the all carbon electrode-based flexible C–PSCs with the structure of polyethylene terephthalate (PET)/graphene-silver nanowires (graphene–AgNWs)/SnO2/CH3NH3PbI3/Carbon are successfully prepared by low-temperature solution process. By optimizing the fabrication condition, an optimal efficiency of 9.73% is obtained, which is the highest value reported so far for flexible C–PSCs. Meanwhile, these flexible devices demonstrate superior mechanical robustness in comparison with their counterparts fabricated on flexible indium tin oxide (ITO)/PET substrates as well as excellent long-term durability. The present study can provide a simple way to fabricate low cost, highly efficient and highly stable perovskite solar cells for various applications.

An optimized two-step sequential deposition method to fabricate hole-transport-layer-free carbon-based methyl ammonium lead bromide (MAPbBr3) perovskite solar cells is reported. Small amounts of MABr are introduced into the PbBr2 precursor solution during the first step to prepare MAPbBr3 perovskite films (labeled as MAPB-xMABr), which promotes the conversion of PbBr2 into perovskite phase and results in denser perovskite films with increased crystallinity, lower trap density, and longer carrier lifetime. After optimization, a maximum power conversion efficiency (PCE) of 7.64% (VOC = 1.36 V) is obtained for MAPB-0.2MABr based solar cells. Significantly, the non-encapsulated devices exhibit excellent long-term stability in ambient air (25–30 °C and 20–30% relative humidity), showing no degradation after a year’s exposure. While, it also shows superior thermal stability with PCE retaining 95% of the initial efficiency after 120 h under thermal stress of 80 °C and 40–70% relative humidity.

Two dimensional materials have promising benefits in photoelectronic devices, including facilitating charge transport and reducing defects in perovskite solar cells (PSCs) and photodetectors (PDs) through interface engineering. Herein, a two dimension polymeric material of graphitic carbon nitride quantum dots (g-CNQDs) interlayer is used to modify the SnO2/perovskite interface in both ambient PSCs and PDs to improve the overall performance. The introduction of g-CNQD layer improves the crystalline quality of sequential perovskite absorber with high phase purity, less grain boundaries, low trap states and suppressed carrier recombination due to the intrinsic cross-linkable feature and relatively smooth surface of g-CNQD. As a result, with optimal modification, fully air-processed PSC reached a champion power conversion efficiency of 21.23% with negligible hysteresis, and the PDs had remarkable performance enhancement. Moreover, our PSCs have good stability in ambient air, keeping over 90% of the initial efficiency after 30 days’ exposure.

Perovskite solar cells, bearing the merits of facile preparation and remarkable efficiency, has great potential for bringing the photovoltaic industry to a new generation. The photovoltaic market demands high-efficiency, high stability and low-cost fabrication of perovksite solar cells, especially stability to the humid environment for operation. Here, MAPbI3/agarose photoactive material for humid stable unencapsulated devices has been proposed. These solar cells have been operated in ambient humid environment without glove box, exhibiting efficiency up to 14.66% and retain 90% of its PCE after 1392 h and 60% of initial PCE after 1972 h in ambient humid environment (RH>70%) without encapsulation. FTIR and XPS measurements reveal two critical factors for the improved stability. The molecular level interactions between agarose and MAPbI3 passivates the grain boundaries of perovskite thus preventing its degradation. Moreover, the formation of Li+-agarose complex at the interface between perovskite layer and hole conductive layer, effectively prevents the water uptake of MAPbI3 layer. Both effects of passivation and minimization of hygroscopicity of LiTFSI by agarose lower the decomposition speed of perovskite, which obviously increases the power efficiency and stability of device.

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.

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.

A highly environmentally-friendly ubiquinone 10 (UQ10) based I2-free electrolyte, which is inspired by photosynthesis, is employed in dye-sensitized solar cells (DSSCs) under 100 mW cm−2 (AM 1.5G) illumination. Profiting from this UQ10 based electrolyte a 10% increased power conversion efficiency of 8.18% is achieved compared with the traditional one containing I2 (7.44%). The superior performance of this UQ10 based electrolyte is mainly derived from the lower visible light wastage and high catalytic activity to the counter electrode as revealed by photoelectrochemical characterization. Moreover, being widely adopted in cardiovascular medicine and cosmetics, UQ10 is a very safe and low-cost choice for DSSCs. With the advantages of high power conversion efficiency, bio-safety, universal dye compatibility and diversity of molecular design, UQ10 is very promising to be widely applied in DSSCs, and perovskite based solar cells.