Regulating Charge Carrier Recombination in the Interconnecting Layer to Boost the Efficiency and Stability of Monolithic Perovskite/Organic Tandem Solar Cells.

The charge carriers of single-junction solar cells can be fluently extracted and then collected by electrodes, leading to weak charge carrier accumulation and low energy loss (Eloss ). However, in tandem solar cells (TSCs), it is a considerable challenge to obtain a balance between the densities of the holes and electrons extracted from the two respective subcells to facilitate an efficient recombination in the interconnecting layer (ICL). Herein, a charge-carrier-dynamic management strategy for inorganic perovskite/organic TSCs is proposed, centered on the simultaneous regulation of the defect states of CsPbI1.9 Br1.1 perovskite in the front subcell and hole transport ability from the perovskite to ICL. The target hole density on the perovskite surface and the hole loss before reaching the ICL are significantly improved. As a result, the hole/electron density offset in the ICL can be effectively narrowed, leading to a balanced charge carrier recombination, which reduces the Eloss in TSCs. The resulting inorganic perovskite/organic 0.062-cm2 TSC exhibits a remarkable power conversion efficiency (PCE) of 23.17% with an ultrahigh open-circuit voltage (Voc ) of 2.15 V, and the PCE of the 1.004-cm2 device (21.69%) exhibited a weak size-dependence. This charge-carrier-dynamic management strategy can also effectively enhance the operational and ultraviolet-light stabilities of the TSCs.

AVL9 promotes colorectal carcinoma cell migration via regulating EGFR expression.

BACKGROUND: Despite advanced treatments could inhibit progression of colorectal carcinoma (CRC), the recurrence and metastasis remain challenging issues. Accumulating evidences implicated that AVL9 played a vital role in human cancers, but it's biological function and mechanism in CRC remain unclear. AIM: To investigate the biological role and mechanism of AVL9 in colorectal carcinoma. RESULTS: AVL9 expression was significantly upregulated in tumor tissues than that in matched normal tissues both at mRNA and protein levels. High expression of AVL9 was closely correlated with M status, stages and poor prognosis of colorectal carcinoma (CRC) patients. Functionally, AVL9 overexpression promoted cell migration rather than cell proliferation in vitro, whereas AVL9 knockdown exhibited the contrary results. Mechanistically, AVL9 regulated EGFR expression, and knockdown of EGFR restrained AVL9-induced cell migration. CONCLUSION: These findings demonstrated that AVL9 contributed to CRC cell migration by regulating EGFR expression, suggesting a potential biomarker and treatment target for CRC.

Interfacial Energy Level Tuning for Efficient and Thermostable CsPbI2Br Perovskite Solar Cells.

Inorganic mixed-halide CsPbX3-based perovskite solar cells (PeSCs) are emerging as one of the most promising types of PeSCs on account of their thermostability compared to organic-inorganic hybrid counterparts. However, dissatisfactory device performance and high processing temperature impede their development for viable applications. Herein, a facile route is presented for tuning the energy levels and electrical properties of sol-gel-derived ZnO electron transport material (ETM) via the doping of a classical alkali metal carbonate Cs2CO3. Compared to bare ZnO, Cs2CO3-doped ZnO possesses more favorable interface energetics in contact with the CsPbI2Br perovskite layer, which can reduce the ohmic loss to a negligible level. The optimized PeSCs achieve an improved open-circuit voltage of 1.28 V, together with an increase in fill factor and short-circuit current. The optimized power conversion efficiencies of 16.42% and 14.82% are realized on rigid glass substrate and flexible plastic substrate, respectively. A high thermostability can be simultaneously obtained via defect passivation at the Cs2CO3-doped ZnO/CsPbI2Br interface, and 81% of the initial efficiency is retained after aging for 200 h at 85 °C.

Recent Progress in Organic Photodetectors and their Applications.

Organic photodetectors (OPDs) have attracted continuous attention due to their outstanding advantages, such as tunability of detecting wavelength, low-cost manufacturing, compatibility with lightweight and flexible devices, as well as ease of processing. Enormous efforts on performance improvement and application of OPDs have been devoted in the past decades. In this Review, recent advances in device architectures and operation mechanisms of phototransistor, photoconductor, and photodiode based OPDs are reviewed with a focus on the strategies aiming at performance improvement. The application of OPDs in spectrally selective detection, wearable devices, and integrated optoelectronics are also discussed. Furthermore, some future prospects on the research challenges and new opportunities of OPDs are covered.

Recent progress of light manipulation strategies in organic and perovskite solar cells.

Organic and perovskite solar cells are suffering from the insufficient utilization of incident light and thus low light harvesting efficiency despite their rapid progress in the past decade. In this regard, light manipulation strategies have attracted numerous attention to solve this inherent limit. Herein, the recent advances in light manipulation techniques in this area are overviewed. The light manipulation mechanisms are illustrated to classify the structures. Various light manipulation structures, fabrication techniques, and corresponding results are given and discussed, addressing the suppression of surface reflection, nano/micro-structure-induced light scattering, and the plasmonic effects with periodic metallic patterns and metallic nanoparticles. A brief perspective on future research is also proposed for pursuing broadband light harvesting.

High-Efficiency Perovskite Light-Emitting Diodes with Synergetic Outcoupling Enhancement.

Perovskite light-emitting diodes (PeLEDs) show great application potential in high-quality flat-panel displays and solid-state lighting due to their steadily improved efficiency, tunable colors, narrow emission peak, and easy solution-processing capability. However, because of high optical confinement and nonradiative charge recombination during electron-photon conversion, the highest reported efficiency of PeLEDs remains far behind that of their conventional counterparts, such as inorganic LEDs, organic LEDs, and quantum-dot LEDs. Here a facile route is demonstrated by adopting bioinspired moth-eye nanostructures at the front electrode/perovskite interface to enhance the outcoupling efficiency of waveguided light in PeLEDs. As a result, the maximum external quantum efficiency and current efficiency of the modified cesium lead bromide (CsPbBr3 ) green-emitting PeLEDs are improved to 20.3% and 61.9 cd A-1 , while retaining spectral and angular independence. Further reducing light loss in the substrate mode using a half-ball lens, efficiencies of 28.2% and 88.7 cd A-1 are achieved, which represent the highest values reported to date for PeLEDs. These results represent a substantial step toward achieving practical applications of PeLEDs.

Synergetic Transparent Electrode Architecture for Efficient Non-Fullerene Flexible Organic Solar Cells with >12% Efficiency.

Flexible organic solar cells (OSCs) are considered one key component in wearable, intelligent electronics due to the unique capacity for highly flexible renewable energy sources. However, it is urgently required to enhance their efficiency, as it is far inferior to that of their conventional, glass-based counterparts. To boost the performance of flexible OSCs on plastic substrates, we here present a synergetic transparent electrode structure, which combines electrically conductive silver nanowires, a sol-gel-derived ZnO planarization layer, and imprinted light-trapping nanostructures. This synergetic composite electrode exhibits good properties in terms of optical transparency, electrical conductivity, mechanical flexibility, and low-temperature processability. As a result, the single-junction non-fullerene-based flexible OSCs achieve a power conversion efficiency exceeding 12% due to the synergetic interplay between broadband light trapping and suppressed charge recombination loss. Moreover, these flexible OSCs are repeatedly bendable in both inward and outward bending directions, retaining over 60% of the initial efficiency after 1000 cycles of the bending test at a 3.0 mm radius. These results convey a clear depiction of the practicality of flexible OSCs in a variety of high-performance flexible applications.

Balanced Partnership between Donor and Acceptor Components in Nonfullerene Organic Solar Cells with >12% Efficiency.

Relative to electron donors for bulk heterojunction organic solar cells (OSCs), electron acceptors that absorb strongly in the visible and even near-infrared region are less well developed, which hinders the further development of OSCs. Fullerenes as traditional electron acceptors have relatively weak visible absorption and limited electronic tunability, which constrains the optical and electronic properties required of the donor. Here, high-performance fullerene-free OSCs based on a combination of a medium-bandgap polymer donor (FTAZ) and a narrow-bandgap nonfullerene acceptor (IDIC), which exhibit complementary absorption, matched energy levels, and blend with pure phases on the exciton diffusion length scale, are reported. The single-junction OSCs based on the FTAZ:IDIC blend exhibit power conversion efficiencies up to 12.5% with a certified value of 12.14%. Transient absorption spectroscopy reveals that exciting either the donor or the acceptor component efficiently generates mobile charges, which do not suffer from recombination to triplet states. Balancing photocurrent generation between the donor and nonfullerene acceptor removes undesirable constraints on the donor imposed by fullerene derivatives, opening a new avenue toward even higher efficiency for OSCs.

Polymer Solar Cells with 90% External Quantum Efficiency Featuring an Ideal Light- and Charge-Manipulation Layer.

Rapid progress in the power conversion efficiency (PCE) of polymer solar cells (PSEs) is beneficial from the factors that match the irradiated solar spectrum, maximize incident light absorption, and reduce photogenerated charge recombination. To optimize the device efficiency, a nanopatterned ZnO:Al2 O3 composite film is presented as an efficient light- and charge-manipulation layer (LCML). The Al2 O3 shells on the ZnO nanoparticles offer the passivation effect that allows optimal electron collection by suppressing charge-recombination loss. Both the increased refractive index and the patterned deterministic aperiodic nanostructure in the ZnO:Al2 O3 LCML cause broadband light harvesting. Highly efficient single-junction PSCs for different binary blends are obtained with a peak external quantum efficiency of up to 90%, showing certified PCEs of 9.69% and 13.03% for a fullerene blend of PTB7:PC71 BM and a nonfullerene blend, FTAZ:IDIC, respectively. Because of the substantial increase in efficiency, this method unlocks the full potential of the ZnO:Al2 O3 LCML toward future photovoltaic applications.

Transparent organic light-emitting diodes with balanced white emission by minimizing waveguide and surface plasmonic loss.

It is challenging in realizing high-performance transparent organic light-emitting diodes (OLEDs) with symmetrical light emission to both sides. Herein, an efficient transparent OLED with highly balanced white emission to both sides is demonstrated by integrating quasi-periodic nanostructures into the organic emitter and the metal-dielectric composite top electrode, which can simultaneously suppressing waveguide and surface plasmonic loss. The power efficiency and external quantum efficiency are raised to 83.5 lm W-1 and 38.8%, respectively, along with a bi-directional luminance ratio of 1.26. The proposed scheme provides a facile route for extending application scope of transparent OLEDs for future transparent displays and lightings.

Efficient Color-Stable Inverted White Organic Light-Emitting Diodes with Outcoupling-Enhanced ZnO Layer.

Inverted organic light-emitting diode (OLED) has attracted extensive attention due to the demand in active-matrix OLED display panels as its geometry enables the direct connection with n-channel transistor backplane on the substrate. One key challenge of high-performance inverted OLED is an efficient electron-injection layer with superior electrical and optical properties to match the indium tin oxide cathode on substrate. We here propose a synergistic electron-injection architecture using surface modification of ZnO layer to simultaneously promote electron injection into organic emitter and enhance out-coupling of waveguided light. An efficient inverted white OLED is realized by introducing the nanoimprinted aperiodic nanostructure of ZnO for broadband and angle-independent light out-coupling and inserting an n-type doped interlayer for energy level tuning and injection barrier lowering. As a result, the optimized inverted white OLEDs have an external quantum efficiency of 42.4% and a power efficiency of 85.4 lm W1-, which are accompanied by the superiority of angular color stability over the visible wavelength range. Our results may inspire a promising approach to fabricate high-efficiency inverted OLEDs for large-scale display panels.

Light outcoupling enhanced flexible organic light-emitting diodes.

Flexible organic light-emitting diodes (OLEDs) are emerging as a leading technology for rollable and foldable display applications. For the development of high-performance flexible OLEDs on plastic substrate, we report a transparent nanocomposite electrode with superior mechanical, electrical, and optical properties, which is realized by integrating the nanoimprinted quasi-random photonic structures into the ultrathin metal/dielectric stack to collectively optimize the electrical conduction and light outcoupling capabilities. The resulting flexible OLEDs with green emission yield the enhanced device efficiency, reaching the maximum external quantum efficiency of 43.7% and luminous efficiency of 154.9 cd/A, respectively.

Microcavity-Free Broadband Light Outcoupling Enhancement in Flexible Organic Light-Emitting Diodes with Nanostructured Transparent Metal-Dielectric Composite Electrodes.

Flexible organic light-emitting diodes (OLEDs) hold great promise for future bendable display and curved lighting applications. One key challenge of high-performance flexible OLEDs is to develop new flexible transparent conductive electrodes with superior mechanical, electrical, and optical properties. Herein, an effective nanostructured metal/dielectric composite electrode on a plastic substrate is reported by combining a quasi-random outcoupling structure for broadband and angle-independent light outcoupling of white emission with an ultrathin metal alloy film for optimum optical transparency, electrical conduction, and mechanical flexibility. The microcavity effect and surface plasmonic loss can be remarkably reduced in white flexible OLEDs, resulting in a substantial increase in the external quantum efficiency and power efficiency to 47.2% and 112.4 lm W(-1).

Single-junction polymer solar cells exceeding 10% power conversion efficiency.

A single-junction polymer solar cell with an efficiency of 10.1% is demonstrated by using deterministic aperiodic nanostructures for broadband light harvesting with optimum charge extraction. The performance enhancement is ascribed to the self-enhanced absorption due to collective effects, including pattern-induced anti-reflection and light scattering, as well as surface plasmonic resonance, together with a minimized recombination probability.

High-performance flexible organic light-emitting diodes using embedded silver network transparent electrodes.

Because of their mechanical flexibility, organic light-emitting diodes (OLEDs) hold great promise as a leading technology for display and lighting applications in wearable electronics. The development of flexible OLEDs requires high-quality transparent conductive electrodes with superior bendability and roll-to-roll manufacturing compatibility to replace indium tin oxide (ITO) anodes. Here, we present a flexible transparent conductor on plastic with embedded silver networks which is used to achieve flexible, highly power-efficient large-area green and white OLEDs. By combining an improved outcoupling structure for simultaneously extracting light in waveguide and substrate modes and reducing the surface plasmonic losses, flexible white OLEDs exhibit a power efficiency of 106 lm W(-1) at 1000 cd m(-2) with angular color stability, which is significantly higher than all other reports of flexible white OLEDs. These results represent an exciting step toward the realization of ITO-free, high-efficiency OLEDs for use in a wide variety of high-performance flexible applications.

Light manipulation for organic optoelectronics using bio-inspired moth's eye nanostructures.

Organic-based optoelectronic devices, including light-emitting diodes (OLEDs) and solar cells (OSCs) hold great promise as low-cost and large-area electro-optical devices and renewable energy sources. However, further improvement in efficiency remains a daunting challenge due to limited light extraction or absorption in conventional device architectures. Here we report a universal method of optical manipulation of light by integrating a dual-side bio-inspired moth's eye nanostructure with broadband anti-reflective and quasi-omnidirectional properties. Light out-coupling efficiency of OLEDs with stacked triple emission units is over 2 times that of a conventional device, resulting in drastic increase in external quantum efficiency and current efficiency to 119.7% and 366 cd A(-1) without introducing spectral distortion and directionality. Similarly, the light in-coupling efficiency of OSCs is increased 20%, yielding an enhanced power conversion efficiency of 9.33%. We anticipate this method would offer a convenient and scalable way for inexpensive and high-efficiency organic optoelectronic designs.

[Effect of VEGFR1 gene silencing by shRNA on proliferation, migration and apoptosis of U937 line].

OBJECTIVE: To investigate the effects of lentivirus-mediated RNA interference targeting vascular endothelial growth factor receptor 1 (VEGFR1) gene on the proliferation, migration and apoptosis of leukemic cell line U937. METHODS: Short hairpin RNAs (shRNA) targeting VEGFR-1 was synthesized and cloned into pRNAT-U6.2 lentiviral vector. The expression vectors were transfected into 293T cell line to produce packaged lentivirus. After infected with the packaged lentivirus, the expression of VEGFR-1 gene of U937 cells at mRNA and protein level was detected by real-time PCR and Western blot. VEGF production by the cells was determined by ELISA. Cell proliferation and survival under regular culture and in the presence of cytarabine (Ara-C) was determined by CCK-8 assay. Migration assays were performed by 5 µm pore transwell inserts. RESULTS: The lentiviral shRNA vector targeting VEGFR-1 was successfully constructed and transfected into U937 cells. The shRNA vector effectively inhibited the expression of VEGFR-1 gene in U937 cell line at mRNA and protein levels. As compared to that of the control, the proliferation rate of U937-shVEGFR-1 cells reduced; The VEGF production and migrated cell number of U937-shVEGFR-1 cells decreased dramatically. After treated with Ara-C, the inhibition rate and apoptotic rate of U937-shVEGFR-1 cells increased significantly. The number of migrated cells in the KD group under regular culture and in the presence of VEGF was markedly lower than that in the NC group and CON group. Bevacizumab could decrease the number of migrated cells in the NC group and CON group, but could not in the KD group. CONCLUSIONS: Lentivirus-mediated RNA interference targeting VEGFR1 gene reduces the proliferation, migration of U937 cell line and enhances its sensitivity to Ara-C.