| 1. |
- Zhang, Lixiu, et al.
(författare)
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Advances in the Application of Perovskite Materials
- 2023
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Ingår i: NANO-MICRO LETTERS. - : SHANGHAI JIAO TONG UNIV PRESS. - 2311-6706. ; 15:1
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Forskningsöversikt (refereegranskat)abstract
- Nowadays, the soar of photovoltaic performance of perovskite solar cells has set off a fever in the study of metal halide perovskite materials. The excellent optoelectronic properties and defect tolerance feature allow metal halide perovskite to be employed in a wide variety of applications. This article provides a holistic review over the current progress and future prospects of metal halide perovskite materials in representative promising applications, including traditional optoelectronic devices (solar cells, light-emitting diodes, photodetectors, lasers), and cutting-edge technologies in terms of neuromorphic devices (artificial synapses and memristors) and pressure-induced emission. This review highlights the fundamentals, the current progress and the remaining challenges for each application, aiming to provide a comprehensive overview of the development status and a navigation of future research for metal halide perovskite materials and devices.
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| 2. |
- Chen, Mengyun, et al.
(författare)
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Kinetically Controlled Synthesis of Quasi-Square CsPbI3 Nanoplatelets with Excellent Stability
- 2023
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Ingår i: Small. - : WILEY-V C H VERLAG GMBH. - 1613-6810 .- 1613-6829.
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Tidskriftsartikel (refereegranskat)abstract
- Nanoplatelets (NPLs) share excellent luminescent properties with their symmetric quantum dots counterparts and entail special characters benefiting from the shape, like the thickness-dependent bandgap and anisotropic luminescence. However, perovskite NPLs, especially those based on iodide, suffer from poor spectral and phase stability. Here, stable CsPbI3 NPLs obtained by accelerating the crystallization process in ambient-condition synthesis are reported. By this kinetic control, the rectangular NPLs into quasi-square NPLs are tuned, where enlarged width endows the NPLs with a lower surface-area-to-volume ratio (S/V ratio), leading to lower surficial energy and thus improved endurance against NPL fusion (cause for spectral shift or phase transformation). The accelerated crystallization, denoting the fast nucleation and short period of growth in this report, is enabled by preparing a precursor with complete transformation of PbI2 into intermediates (PbI3-), through an additional iodide supplier (e.g., zinc iodide). The excellent color stability of the materials remains in the light-emitting diodes under various bias stresses.
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| 3. |
- Yang, Fei, et al.
(författare)
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Efficient and Spectrally Stable Blue Perovskite Light-Emitting Diodes Based on Potassium Passivated Nanocrystals
- 2020
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Ingår i: Advanced Functional Materials. - : WILEY-V C H VERLAG GMBH. - 1616-301X .- 1616-3028. ; 30:10
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Tidskriftsartikel (refereegranskat)abstract
- Metal halide perovskites have aroused tremendous interest in the past several years for their promising applications in display and lighting. However, the development of blue perovskite light-emitting diodes (PeLEDs) still lags far behind that of their green and red cousins due to the difficulty in obtaining high-quality blue perovskite emissive layers. In this study, a simple approach is conceived to improve the emission and electrical properties of blue perovskites. By introducing an alkali metal ion to occupy some sites of peripheral suspended organic ligands, the nonradiative recombination is suppressed, and, consequently, blue CsPb(Br/Cl)(3) nanocrystals with a high photoluminescence quantum efficiency of 38.4% are obtained. The introduced K+ acts as a new type of metal ligand, which not only suppresses nonradiative pathways but also improves the charge carrier transport of the perovskite nanocrystals. With further engineering of the device structure to balance the charge injection rate, a spectrally stable and efficient blue PeLED with a maximum external quantum efficiency of 1.96% at the emission peak of 477 nm is fabricated.
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| 4. |
- Zhang, Liangdong, et al.
(författare)
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Bright Free Exciton Electroluminescence from Mn-Doped Two-Dimensional Layered Perovskites
- 2019
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Ingår i: The Journal of Physical Chemistry Letters. - : AMER CHEMICAL SOC. - 1948-7185. ; 10:11, s. 3171-3175
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Tidskriftsartikel (refereegranskat)abstract
- Two-dimensional (2D) perovskites incorporating hydrophobic organic spacer cations show improved film stability and morphology compared to their three-dimensional (3D) counterparts. However, 2D perovskites usually exhibit low photoluminescence quantum efficiency (PLQE) owing to strong exciton-phonon interaction at room temperature, which limits their efficiency in light-emitting diodes (LEDs). Here, we demonstrate that the device performance of 2D perovskite LEDs can be significantly enhanced by doping Mn(2+)in (benzimidazolium)(2)PbI4 2D perovskite films to suppress the exciton-phonon interaction. The distorted [PbI6](4-) octahedra by Mn-doping and the rigid benzimidazolium (BIZ) ring without branched chains in the 2D perovskite structure lead to improved crystallinity and rigidity of the perovskites, resulting in suppressed phonon-exciton interaction and enhanced PLQE. On the basis of this strategy, for the first time, we report yellow electroluminescence from free excitons in 2D (n = 1) perovskites with a maximum brightness of 225 cd m(-2) and a peak EQE of 0.045%.
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| 5. |
- Zhang, Yuehui, et al.
(författare)
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Increased uterine androgen receptor protein abundance results in implantation and mitochondrial defects in pregnant rats with hyperandrogenism and insulin resistance. : Deciphering the role of uterine AR in PCOS during early pregnancy
- 2021
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Ingår i: Journal of molecular medicine (Berlin, Germany). - : Springer Science and Business Media LLC. - 1432-1440 .- 0946-2716. ; 99, s. 1427-1446
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Tidskriftsartikel (refereegranskat)abstract
- In this study, we show that during normal rat pregnancy, there is a gestational stage-dependent decrease in androgen receptor (AR) abundance in the gravid uterus and that this is correlated with the differential expression of endometrial receptivity and decidualization genes during early and mid-gestation. In contrast, exposure to 5α-dihydrotestosterone (DHT) and insulin (INS) or DHT alone significantly increased AR protein levels in the uterus in association with the aberrant expression of endometrial receptivity and decidualization genes, as well as disrupted implantation. Next, we assessed the functional relevance of the androgen-AR axis in the uterus for reproductive outcomes by treating normal pregnant rats and pregnant rats exposed to DHT and INS with the anti-androgen flutamide. We found that AR blockage using flutamide largely attenuated the DHT and INS-induced maternal endocrine, metabolic, and fertility impairments in pregnant rats in association with suppressed induction of uterine AR protein abundance and androgen-regulated response protein and normalized expression of several endometrial receptivity and decidualization genes. Further, blockade of AR normalized the expression of the mitochondrial biogenesis marker Nrf1 and the mitochondrial functional proteins Complexes I and II, VDAC, and PHB1. However, flutamide treatment did not rescue the compromised mitochondrial structure resulting from co-exposure to DHT and INS. These results demonstrate that functional AR protein is an important factor for gravid uterine function. Impairments in the uterine androgen-AR axis are accompanied by decreased endometrial receptivity, decidualization, and mitochondrial dysfunction, which might contribute to abnormal implantation in pregnant PCOS patients with compromised pregnancy outcomes and subfertility. KEY MESSAGES: The proper regulation of uterine androgen receptor (AR) contributes to a normal pregnancy process, whereas the aberrant regulation of uterine AR might be linked to polycystic ovary syndrome (PCOS)-induced pregnancy-related complications. In the current study, we found that during normal rat pregnancy there is a stage-dependent decrease in AR abundance in the gravid uterus and that this is correlated with the differential expression of the endometrial receptivity and decidualization genes Spp1, Prl, Igfbp1, and Hbegf. Pregnant rats exposed to 5α-dihydrotestosterone (DHT) and insulin (INS) or to DHT alone show elevated uterine AR protein abundance and implantation failure related to the aberrant expression of genes involved in endometrial receptivity and decidualization in early to mid-gestation. Treatment with the anti-androgen flutamide, starting from pre-implantation, effectively prevents DHT + INS-induced defects in endometrial receptivity and decidualization gene expression, restores uterine mitochondrial homeostasis, and increases the pregnancy rate and the numbers of viable fetuses. This study adds to our understanding of the mechanisms underlying poor pregnancy outcomes in PCOS patients and the possible therapeutic use of anti-androgens, including flutamide, after spontaneous conception.
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| 6. |
- Hu, Min, et al.
(författare)
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Hyperandrogenism and insulin resistance induce gravid uterine defects in association with mitochondrial dysfunction and aberrant ROS production.
- 2019
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Ingår i: American journal of physiology. Endocrinology and metabolism. - : American Physiological Society. - 1522-1555 .- 0193-1849. ; 316:5
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Tidskriftsartikel (refereegranskat)abstract
- Women with polycystic ovary syndrome (PCOS) are at increased risk of miscarriage, which often accompanies the hyperandrogenism and insulin resistance seen in these patients. However, neither the combinatorial interaction between these two PCOS-related etiological factors nor the mechanisms of their actions in the uterus during pregnancy are well understood. We hypothesised that hyperandrogensim and insulin resistance exert a causative role in miscarriage by inducing defects in uterine function that are accompanied by mitochondrial-mediated oxidative stress, inflammation and perturbed gene expression. Here we tested this hypothesis by studying the metabolic, endocrine and uterine abnormalities in pregnant rats after exposure to daily injection of 5α-dihydrotestosterone (DHT, 1.66 mg/kg body weight/day) and/or insulin (6.0 IU/day) from gestational day 7.5 to 13.5. We showed that while DHT-exposed and insulin-exposed pregnant rats presented impaired insulin sensitivity, DHT+insulin-exposed pregnant rats exhibited hyperandrogenism and peripheral insulin resistance, which mirrors pregnant PCOS patients. Compared to controls, hyperandrogenism and insulin resistance in the dam was associated with alterations in uterine morphology and aberrant expression of genes responsible for decidualization, placentation, angiogenesis and insulin signaling. Moreover, we observed changes in uterine mitochondrial function and homeostasis and suppression of both oxidative and antioxidative defenses in response to the hyperandrogenism and insulin resistance. These findings demonstrate that hyperandrogenism and insulin resistance induce mitochondria-mediated damage and a resulting imbalance between oxidative and antioxidative stress responses in the gravid uterus.
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| 7. |
- Hu, Min, et al.
(författare)
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Perturbed ovarian and uterine glucocorticoid receptor signaling accompanies the balanced regulation of mitochondrial function and NFκB-mediated inflammation under conditions of hyperandrogenism and insulin resistance.
- 2019
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Ingår i: Life sciences. - : Elsevier BV. - 1879-0631 .- 0024-3205. ; 232
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Tidskriftsartikel (refereegranskat)abstract
- This study aimed to determine whether glucocorticoid receptor (GR) signaling, mitochondrial function, and local inflammation in the ovary and uterus are intrinsically different in rats with hyperandrogenism and insulin resistance compared to controls.Female Sprague Dawley rats were exposed to daily injections of human chorionic gonadotropin and/or insulin.In both the ovary and the uterus, decreased expression of the two GR isoforms was concurrent with increased expression of Fkbp51 but not Fkbp52 mRNA in hCG+insulin-treated rats. However, these rats exhibited contrasting regulation of Hsd11b1 and Hsd11b2 mRNAs in the two tissues. Further, the expression of several oxidative phosphorylation-related proteins decreased in the ovary and uterus following hCG and insulin stimulation, in contrast to increased expression of many genes involved in mitochondrial function and homeostasis. Additionally, hCG+insulin-treated rats showed increased expression of ovarian and uterine NFκB signaling proteins and Tnfaip3 mRNA. The mRNA expression of Il1b, Il6, and Mmp2 was decreased in both tissues, while the mRNA expression of Tnfa, Ccl2, Ccl5, and Mmp3 was increased in the uterus. Ovaries and uteri from animals co-treated with hCG and insulin showed increased collagen deposition compared to controls.Our observations suggest that hyperandrogenism and insulin resistance disrupt ovarian and uterine GR activation and trigger compensatory or adaptive effects for mitochondrial homeostasis, allowing tissue-level maintenance of mitochondrial function in order to limit ovarian and uterine dysfunction. Our study also suggests that hyperandrogenism and insulin resistance activate NFκB signaling resulting in aberrant regulation of inflammation-related gene expression.
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| 8. |
- Qian, Deping, et al.
(författare)
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Design rules for minimizing voltage losses in high-efficiency organic solar cells
- 2018
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Ingår i: Nature Materials. - : NATURE PUBLISHING GROUP. - 1476-1122 .- 1476-4660. ; 17:8, s. 703-
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Tidskriftsartikel (refereegranskat)abstract
- The open-circuit voltage of organic solar cells is usually lower than the values achieved in inorganic or perovskite photovoltaic devices with comparable bandgaps. Energy losses during charge separation at the donor-acceptor interface and non-radiative recombination are among the main causes of such voltage losses. Here we combine spectroscopic and quantum-chemistry approaches to identify key rules for minimizing voltage losses: (1) a low energy offset between donor and acceptor molecular states and (2) high photoluminescence yield of the low-gap material in the blend. Following these rules, we present a range of existing and new donor-acceptor systems that combine efficient photocurrent generation with electroluminescence yield up to 0.03%, leading to non-radiative voltage losses as small as 0.21 V. This study provides a rationale to explain and further improve the performance of recently demonstrated high-open-circuit-voltage organic solar cells.
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| 9. |
- Qing, Jian, et al.
(författare)
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High-Quality Ruddlesden-Popper Perovskite Films Based on In Situ Formed Organic Spacer Cations
- 2019
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Ingår i: Advanced Materials. - : WILEY-V C H VERLAG GMBH. - 0935-9648 .- 1521-4095. ; 31:41
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Tidskriftsartikel (refereegranskat)abstract
- Ruddlesden-Popper perovskites (RPPs), consisting of alternating organic spacer layers and inorganic layers, have emerged as a promising alternative to 3D perovskites for both photovoltaic and light-emitting applications. The organic spacer layers provide a wide range of new possibilities to tune the properties and even provide new functionalities for RPPs. However, the preparation of state-of-the-art RPPs requires organic ammonium halides as the starting materials, which need to be ex situ synthesized. A novel approach to prepare high-quality RPP films through in situ formation of organic spacer cations from amines is presented. Compared with control devices fabricated from organic ammonium halides, this new approach results in similar (and even better) device performance for both solar cells and light-emitting diodes. High-quality RPP films are fabricated based on different types of amines, demonstrating the universality of the approach. This approach not only represents a new pathway to fabricate efficient devices based on RPPs, but also provides an effective method to screen new organic spacers with further improved performance.
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| 10. |
- Ren, Luyao, et al.
(författare)
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Quartet DNA reference materials and datasets for comprehensively evaluating germline variant calling performance
- 2023
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Ingår i: Genome Biology. - : BioMed Central (BMC). - 1465-6906 .- 1474-760X. ; 24:1
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Genomic DNA reference materials are widely recognized as essential for ensuring data quality in omics research. However, relying solely on reference datasets to evaluate the accuracy of variant calling results is incomplete, as they are limited to benchmark regions. Therefore, it is important to develop DNA reference materials that enable the assessment of variant detection performance across the entire genome.RESULTS: We established a DNA reference material suite from four immortalized cell lines derived from a family of parents and monozygotic twins. Comprehensive reference datasets of 4.2 million small variants and 15,000 structural variants were integrated and certified for evaluating the reliability of germline variant calls inside the benchmark regions. Importantly, the genetic built-in-truth of the Quartet family design enables estimation of the precision of variant calls outside the benchmark regions. Using the Quartet reference materials along with study samples, batch effects are objectively monitored and alleviated by training a machine learning model with the Quartet reference datasets to remove potential artifact calls. Moreover, the matched RNA and protein reference materials and datasets from the Quartet project enables cross-omics validation of variant calls from multiomics data.CONCLUSIONS: The Quartet DNA reference materials and reference datasets provide a unique resource for objectively assessing the quality of germline variant calls throughout the whole-genome regions and improving the reliability of large-scale genomic profiling.
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| 11. |
- Wang, Heyong, 1989-, et al.
(författare)
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Impacts of the Lattice Strain on Perovskite Light-Emitting Diodes
- 2023
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Ingår i: Advanced Energy Materials. - : Wiley-V C H Verlag GMBH. - 1614-6832 .- 1614-6840. ; 13:33
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Tidskriftsartikel (refereegranskat)abstract
- The development of perovskite light-emitting diodes (PeLEDs) with both high efficiency and excellent stability remains challenging. Herein, a strong correlation between the lattice strain in perovskite films and the stability of resulting PeLEDs is revealed. Based on high-efficiency PeLEDs, the device lifetime is optimized by rationally tailoring the lattice strain in perovskite films. A PeLED with a high peak external quantum efficiency of 18.2% and a long lifetime of 151 h (T-70, under a current density of 20 mA cm(-2)) is realized with a minimized lattice strain in the perovskite film. In addition, an increase in the lattice strain is found during the long-time device stability test, indicating that the degradation of the local perovskite lattice structure could be one of the degradation mechanisms for long-term stable PeLEDs.
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| 12. |
- Wang, Heyong, et al.
(författare)
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Perovskite-molecule composite thin films for efficient and stable light-emitting diodes
- 2020
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Ingår i: Nature Communications. - : NATURE PUBLISHING GROUP. - 2041-1723. ; 11:1
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Tidskriftsartikel (refereegranskat)abstract
- Although perovskite light-emitting diodes (PeLEDs) have recently experienced significant progress, there are only scattered reports of PeLEDs with both high efficiency and long operational stability, calling for additional strategies to address this challenge. Here, we develop perovskite-molecule composite thin films for efficient and stable PeLEDs. The perovskite-molecule composite thin films consist of in-situ formed high-quality perovskite nanocrystals embedded in the electron-transport molecular matrix, which controls nucleation process of perovskites, leading to PeLEDs with a peak external quantum efficiency of 17.3% and half-lifetime of approximately 100 h. In addition, we find that the device degradation mechanism at high driving voltages is different from that at low driving voltages. This work provides an effective strategy and deep understanding for achieving efficient and stable PeLEDs from both material and device perspectives.
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| 13. |
- Yi, Chang, et al.
(författare)
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Intermediate-phase-assisted low-temperature formation of gamma-CsPbI3 films for high-efficiency deep-red light-emitting devices
- 2020
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Ingår i: Nature Communications. - : Nature Publishing Group. - 2041-1723. ; 11:1
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Tidskriftsartikel (refereegranskat)abstract
- Black phase CsPbI3 is attractive for optoelectronic devices, while usually it has a high formation energy and requires an annealing temperature of above 300 degrees C. The formation energy can be significantly reduced by adding HI in the precursor. However, the resulting films are not suitable for light-emitting applications due to the high trap densities and low photoluminescence quantum efficiencies, and the low temperature formation mechanism is not well understood yet. Here, we demonstrate a general approach for deposition of gamma -CsPbI3 films at 100 degrees C with high photoluminescence quantum efficiencies by adding organic ammonium cations, and the resulting light-emitting diode exhibits an external quantum efficiency of 10.4% with suppressed efficiency roll-off. We reveal that the low-temperature crystallization process is due to the formation of low-dimensional intermediate states, and followed by interionic exchange. This work provides perspectives to tune phase transition pathway at low temperature for CsPbI3 device applications. Exploiting low-temperature formed black phase CsPbI3 for light-emitting applications remains a challenge. Here, the authors propose a method to enable the deposition of gamma -CsPbI3 films at 100C and demonstrate a light-emitting diode with an external quantum efficiency of 10.4% with suppressed efficiency roll-off.
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| 14. |
- Zhang, Jia, et al.
(författare)
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Transport Layer Engineering Toward Lower Threshold for Perovskite Lasers
- 2023
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Ingår i: Advanced Materials. - : WILEY-V C H VERLAG GMBH. - 0935-9648 .- 1521-4095. ; 35:30
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Tidskriftsartikel (refereegranskat)abstract
- Charge-transport layers are essential for achieving electrically pumped perovskite lasers. However, their role in perovskite lasing is not fully understood. Here, the role of charge-transport layers on the lasing actions of perovskite films is explored by investigating the amplified spontaneous emission (ASE) thresholds. A largely reduced ASE threshold and enhanced ASE intensity is demonstrated by introducing an additional hole transport layer poly(triaryl amine) (PTAA). It is shown that the key role of the PTAA layer is to accelerate the hot-carrier cooling process by extracting holes in perovskites. With reduced hot holes, the Auger recombination loss is largely suppressed, resulting in decreased ASE threshold. This argument is further supported by the fact that the ASE threshold can be further reduced from 25.7 to 7.2 mu J cm(-2) upon switching the pumping wavelength from 400 to 500 nm to directly avoid excess hot-hole generation. This work exemplifies how to further reduce the ASE threshold with transport layer engineering through hot-hole manipulation. This is critical to maintaining the excellent gain properties of perovskites when integrating them into electrical devices, paving the way for electrically pumped perovskite lasers.
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| 15. |
- Zhang, Yuehui, et al.
(författare)
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Hyperandrogenism and insulin resistance modulate gravid uterine and placental ferroptosis in PCOS-like rats. : Uterine and placental ferroptosis in pregnant PCOS-like rats
- 2020
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Ingår i: The Journal of endocrinology. - 1479-6805. ; 246:3, s. 247-63
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Tidskriftsartikel (refereegranskat)abstract
- Previous studies in rats showed that maternal exposure to 5α-dihydrotestosterone (DHT) and insulin (INS) from gestational day 7.5 to 13.5 induces hyperandrogenism and insulin resistance (HAIR) and subsequently leads to placental insufficiency and fetal loss. We therefore hypothesized that maternal HAIR triggers ferroptosis in the uterus and placenta in association with fetal loss in pregnant rats. Compared with controls, we found that co-exposure to DHT and INS led to decreased levels of Gpx4 and glutathione (GSH), increased GSH+glutathione disulfide (GSSG) and malondialdehyde (MDA), aberrant expression of ferroptosis-associated genes (Acsl4, Tfrc, Slc7a11, and Gclc), increased iron deposition, and activated ERK/p38/JNK phosphorylation in the gravid uterus. However, in the placenta, DHT and INS exposure only partially altered the expression of ferroptosis-related markers (e.g., Gpx4, GSH+GSSG, MDA, Gls2 and Slc7a11 mRNAs, and phosphorylated p38 levels). In the uteri co-exposed to DHT and INS, we also observed shrunken mitochondria with electron-dense cristae, and increased Dpp4 mRNA expression. In contrast, in placentas co-exposed to DHT and INS we found decreased Dpp4 mRNA expression and increased Cisd1 mRNA expression. Further, DHT+INS-exposed pregnant rats exhibited decreased apoptosis in the uterus and increased necroptosis in the placenta. Our findings suggest that maternal HAIR causes the activation of ferroptosis in the gravid uterus and placenta, although this is mediated via different mechanisms operating at the molecular and cellular levels. Furthermore, our data suggest other cell death pathways may play a role in coordinating or compensating for HAIR-induced ferroptosis when the gravid uterus and placenta are dysfunctional.
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| 16. |
- Zhang, Yuehui, et al.
(författare)
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Hyperandrogenism and insulin resistance modulate gravid uterine and placental ferroptosis in PCOS-like rats.
- 2020
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Ingår i: Journal of Endocrinology. - : Bioscientifica. - 0022-0795 .- 1479-6805. ; 246:3, s. 247-263
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Tidskriftsartikel (refereegranskat)abstract
- Previous studies in rats showed that maternal exposure to 5α-dihydrotestosterone (DHT) and insulin (INS) from gestational day 7.5 to 13.5 induces hyperandrogenism and insulin resistance (HAIR) and subsequently leads to placental insufficiency and fetal loss. We therefore hypothesized that maternal HAIR triggers ferroptosis in the uterus and placenta in association with fetal loss in pregnant rats. Compared with controls, we found that co-exposure to DHT and INS led to decreased levels of Gpx4 and glutathione (GSH), increased GSH+glutathione disulfide (GSSG) and malondialdehyde (MDA), aberrant expression of ferroptosis-associated genes (Acsl4, Tfrc, Slc7a11, and Gclc), increased iron deposition, and activated ERK/p38/JNK phosphorylation in the gravid uterus. However, in the placenta, DHT and INS exposure only partially altered the expression of ferroptosis-related markers (e.g., Gpx4, GSH+GSSG, MDA, Gls2 and Slc7a11 mRNAs, and phosphorylated p38 levels). In the uteri co-exposed to DHT and INS, we also observed shrunken mitochondria with electron-dense cristae, and increased Dpp4 mRNA expression. In contrast, in placentas co-exposed to DHT and INS we found decreased Dpp4 mRNA expression and increased Cisd1 mRNA expression. Further, DHT+INS-exposed pregnant rats exhibited decreased apoptosis in the uterus and increased necroptosis in the placenta. Our findings suggest that maternal HAIR causes the activation of ferroptosis in the gravid uterus and placenta, although this is mediated via different mechanisms operating at the molecular and cellular levels. Furthermore, our data suggest other cell death pathways may play a role in coordinating or compensating for HAIR-induced ferroptosis when the gravid uterus and placenta are dysfunctional.
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| 17. |
- Ao, Hong, et al.
(författare)
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Orbital climate variability on the northeastern Tibetan Plateau across the Eocene-Oligocene transition
- 2020
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Ingår i: Nature Communications. - : Springer Science and Business Media LLC. - 2041-1723. ; 11:1
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Tidskriftsartikel (refereegranskat)abstract
- The first major build-up of Antarctic glaciation occurred in two consecutive stages across the Eocene-Oligocene transition (EOT): the EOT-1 cooling event at similar to 34.1-33.9Ma and the Oi-1 glaciation event at similar to 33.8-33.6Ma. Detailed orbital-scale terrestrial environmental responses to these events remain poorly known. Here we present magnetic and geochemical climate records from the northeastern Tibetan Plateau margin that are dated precisely from similar to 35.5 to 31Ma by combined magneto- and astro-chronology. These records suggest a hydroclimate transition at similar to 33.7Ma from eccentricity dominated cycles to oscillations paced by a combination of eccentricity, obliquity, and precession, and confirm that major Asian aridification and cooling occurred at Oi-1. We conclude that this terrestrial orbital response transition coincided with a similar transition in the marine benthic delta O-18 record for global ice volume and deep-sea temperature variations. The dramatic reorganization of the Asian climate system coincident with Oi-1 was, thus, a response to coeval atmospheric CO2 decline and continental-scale Antarctic glaciation. Marine records indicate a greenhouse to icehouse climate transition at similar to 34 million years ago, but how the climate changed within continental interiors at this time is less well known. Here, the authors show an orbital climate response shift with aridification on the northeastern Tibetan Plateau during this time.
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| 18. |
- Hu, Min, et al.
(författare)
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Suppression of uterine and placental ferroptosis by N-acetylcysteine in a rat model of polycystic ovary syndrome. : Ferroptosis and N-acetylcysteine
- 2021
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Ingår i: Molecular human reproduction. - : Oxford University Press (OUP). - 1460-2407 .- 1360-9947. ; 27:12
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Tidskriftsartikel (refereegranskat)abstract
- The mechanisms that link hyperandrogenism and insulin resistance to the increased miscarriage rate in women with polycystic ovary syndrome (PCOS) remain elusive. Previous studies demonstrate that increased uterine and placental ferroptosis is associated with oxidative stress-induced fetal loss in a pre-clinical PCOS-like rat model. Here, we investigated the efficacy and molecular mechanism of action of the antioxidant N-acetylcysteine (NAC) in reversing gravid uterine and placental ferroptosis in pregnant rats exposed to 5α-dihydrotestosterone (DHT) and insulin. Molecular and histological analyses showed that NAC attenuated DHT and insulin-induced uterine ferroptosis, including dose-dependent increases in anti-ferroptosis gene content. Changes in other molecular factors after NAC treatment were also observed in the placenta exposed to DHT and insulin, such as increased glutathione peroxidase 4 protein level. Further, increased apoptosis inducing factor mitochondria associated 2 mRNA expression was seen in the placenta but not in the uterus. Additionally, NAC was not sufficient to rescue DHT+insulin-induced mitochondria-morphological abnormalities in the uterus, whereas the same treatment partially reversed such abnormalities in the placenta. Finally, we demonstrated that NAC selectively normalized uterine leukemia inhibitory factor, osteopontin/secreted phosphoprotein 1, progesterone receptor, and homeobox A11 mRNA expression and placental estrogen related receptor beta and trophoblast specific protein alpha mRNA expression. Collectively, our data provide insight into how NAC exerts beneficial effects on differentially attenuating gravid uterine and placental ferroptosis in a PCOS-like rat model with fetal loss. These results indicate that exogenous administration of NAC represents a potential therapeutic strategy in the treatment of hyperandrogenism and insulin resistance-induced uterine and placental dysfunction.
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| 19. |
- Li, Yuchen, et al.
(författare)
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Fabricating an anti-corrosion carbonate coating on Mg-Li alloy by low-temperature plasma
- 2022
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Ingår i: Surface & Coatings Technology. - : Elsevier BV. - 0257-8972 .- 1879-3347. ; 439
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Tidskriftsartikel (refereegranskat)abstract
- Despite the huge demand for ultra-light magnesium-lithium (Mg-Li) alloys, practical applications of Mg-Li alloys are still severely restricted due to their poor corrosion resistance. Here, we report a new method utilizing low-temperature plasma to grow an oxide layer on the Mg-Li alloys in atmospheric condition, which reacts with CO2 and water in the air and consequently transform into a protective coating. The prepared coating has a layered structure consisting of a Mg(OH)(2) inner layer and a Li2CO3 outer layer. The composition distribution can be attributed to the different migration rates between Li+ and Mg2+ during coating formation. The Li2CO3 outer layer is sufficiently compact and very stable, with an ultra-low solubility in water, explaining the superior corrosion resistance of the coating in 3.5% NaCl solution. This simple and eco-friendly surface treatment provides a novel way of fabricating protective coatings on Mg-Li alloys.
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| 20. |
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| 21. |
- Qing, Jian, et al.
(författare)
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Spacer cation engineering in Ruddlesden-Popper perovskites for efficient red light-emitting diodes with recommendation 2020 color coordinates
- 2023
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Ingår i: Applied Surface Science. - : ELSEVIER. - 0169-4332 .- 1873-5584. ; 616
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Tidskriftsartikel (refereegranskat)abstract
- Ruddlesden-Popper perovskites (RPPs) have been demonstrated as a very promising approach for tuning the emission color of perovskite light-emitting diodes (PeLEDs). However, achieving high-performance red PeLEDs with recommendation 2020 color coordinates is still challenging due to the lack of reasonable control over the properties of RPP films. Here, we demonstrate that the judicious selection of spacer cations in RPPs affords a lever for engineering their film properties, including phase distribution, energy funneling process, trap density, and carrier mobility. Four structurally related spacer cations, benzylammonium (BZA), phenylethylammonium (PEA), 3-phenyl-1-propylammonium (PPA), and phenoxyethylammonium (POEA), are studied. Owing to narrow phase distribution, efficient energy funneling, and low trap density, the POEA-based RPP films enable efficient red PeLEDs with a peak external quantum efficiency of 10.3%, a maximum brightness of 1052 cd m- 2, and excellent spectral stability. Significantly, the electroluminescence spectrum represents CIE 1931 color coordinates of (0.71, 0.29), which meets the recommendation 2020 standard (0.708, 0.292). The findings provide useful guidelines for the rational design of new organic spacer cations for RPPs with high performance.
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| 22. |
- Xu, Weidong, et al.
(författare)
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Precisely Controlling the Grain Sizes with an Ammonium Hypophosphite Additive for High-Performance Perovskite Solar Cells
- 2018
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Ingår i: Advanced Functional Materials. - : WILEY-V C H VERLAG GMBH. - 1616-301X .- 1616-3028. ; 28:33
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Tidskriftsartikel (refereegranskat)abstract
- A facile approach to precisely control the perovskite grain sizes is proposed and demonstrated for high-performance photovoltaic (PV) solar cells. With the introduction of various amounts of NH4H2PO2 (AHP) additives into the PbI2/CH3NH3I precursors, the grain scale of CH3NH3PbI3 films can be finely turned from hundreds of nanometer to micrometer scale, allowing evaluating the effects of crystalline grain boundary on trap densities, charge recombination, and PV device performance. The X-ray diffraction and X-ray photoelectron spectroscopy measurements indicate that the formation of intermediates plays a key role in assisting the perovskite crystal growth. The optimized devices show much larger open-circuit voltages (V-OC) up to 1.10 +/- 0.02 V and significantly enhance power conversion efficiencies (PCEs) of 16.5 +/- 0.7%, as compared to the control devices with PCE of 9.4 +/- 1.0% and V-OC of 1.00 +/- 0.03 V. Further investigations confirm that the boosted PV performance origins from the decreased defect densities due to enlarged grain sizes. It is also demonstrated that the approach is general and applicable to other perovskite systems, e.g., HC(NH2)(2)PbI3. The results suggest the promising application of AHP in achieving high-performance perovskite PV devices, and shed light on understanding the grain boundary effects on perovskite optoelectronics.
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| 23. |
- Yang, Xinming, et al.
(författare)
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Cryptotanshinone reverses reproductive and metabolic disturbances in prenatally androgenized rats via regulation of signaling mechanisms and androgen synthesis.
- 2011
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Ingår i: American journal of physiology. Regulatory, integrative and comparative physiology. - : American Physiological Society. - 1522-1490 .- 0363-6119. ; 300:4
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Tidskriftsartikel (refereegranskat)abstract
- This trial explores (i) prenatally androgenized (PNA) rats as a model of polycystic ovary syndrome (PCOS) and (ii) reproductive and metabolic effects of cryptotanshinone in PNA ovaries. On days 16-18 of pregnancy, 10 rats were injected with testosterone propionate (PNA mothers) and 10 with sesame oil (control mothers). At age 3 mo, 12 female offspring from each group were randomly assigned to receive saline and 12 cryptotanshinone treatment during 2 weeks. Before treatment, compared with the 24 controls, the 24 PNA rats had (i) disrupted estrus cycles, (ii) higher 17-hydroxyprogesterone, (P = 0.030), androstenedione (P = 0.016), testosterone and insulin (Ps = 0.000), and glucose (P = 0.047) levels, and (iii) higher areas under the curve (AUC) for glucose (AUC-Glu, P = 0.025) and homeostatic model assessment for insulin resistance (HOMA-IR, P = 0.008). After treatment, compared with vehicle-treated PNA rats, cryptotanshinone-treated PNA rats had (i) improved estrus cycles (P = 0.045), (ii) reduced 17-hydroxyprogesterone (P = 0.041), androstenedione (P = 0.038), testosterone (P = 0.003), glucose (P = 0.036), and insulin (P = 0.041) levels, and (iii) lower AUC-Glu (P = 0.045) and HOMA-IR (P = 0.024). Western blot showed that cryptotanshinone reversed the altered protein expressions of insulin receptor substrate-1 and -2, phosphatidylinositol 3-kinase p85α, glucose transporter-4, ERK-1, and 17α-hydroxylase within PNA ovaries. We conclude that PNA model rats exhibit reproductive and metabolic phenotypes of human PCOS and that regulation of key molecules in insulin signaling and androgen synthesis within PNA ovaries may explain cryptotanshinone's therapeutic effects.
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| 24. |
- Yu, Hongling, et al.
(författare)
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Color-Stable Blue Light-Emitting Diodes Enabled by Effective Passivation of Mixed Halide Perovskites
- 2021
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Ingår i: The Journal of Physical Chemistry Letters. - : American Chemical Society (ACS). - 1948-7185. ; 12:26, s. 6041-6047
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Tidskriftsartikel (refereegranskat)abstract
- Bandgap tuning through mixing halide anions is one of the most attractive features for metal halide perovskites. However, mixed halide perovskites usually suffer from phase segregation under electrical biases. Herein, we obtain high-performance and color-stable blue perovskite LEDs (PeLEDs) based on mixed bromide/ chloride three-dimensional (3D) structures. We demonstrate that the color instability of CsPb(Br1-xClx)(3) PeLEDs results from surface defects at perovskite grain boundaries. By effective defect passivation, we achieve color-stable blue electroluminescence from CsPb(Br1-xClx)(3) PeLEDs, with maximum external quantum efficiencies of up to 4.5% and high luminance of up to 5351 cd m(-2) in the sky-blue region (489 nm). Our work provides new insights into the color instability issue of mixed halide perovskites and can spur new development of high-performance and color-stable blue PeLEDs.
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| 25. |
- Yu, Hongling, 1987-
(författare)
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Color Tuning for Perovskite Light-Emitting Diodes
- 2020
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Metal halide perovskites (MHPs) are recognized as promising semiconductor materials for a variety of optical and electrical device applications due to their cost-effective and outstanding optoelectronic properties. As one of the most significant applications, perovskite light-emitting diodes (PeLEDs) hold promise for future lighting and display technologies, attributed to their high photoluminescence quantum yield (PLQY), high color purity, and tunable emission color. The emission colors of PeLEDs can be tuned by mixing the halide anions, adjusting the size of perovskite nanocrystals, or changing the dimensionality of perovskites. However, in practice, all these different approaches have their own advantages and challenges. This thesis centres around the color tunability of perovskites, aiming to develop PeLEDs with different colors using different approaches.We first demonstrate red and near-infrared PeLEDs using a straightforward approach – in situ solution-processed perovskite quantum dots (PQDs). PQDs prepared from colloidal approaches are widely reported and used in LEDs. In contrast, PQDs prepared from the in situ approaches are hardly reported, although they have advantages for device applications. By employing aromatic ammonium iodide (1-naphthylmethyl ammonium iodide, NMAI) as an agent into perovskite precursor solutions, together with annealing temperature modulation, we obtain in situ grown PQDs delivering high external quantum efficiencies (EQEs) of up to 11.0% with tunable electroluminescence (EL) spectra (667 - 790 nm). Our in situ generated PQDs based on pure-halogen perovskites can be easily obtained through a simple deposition process and free of phase segregation, making them a more promising approach for tuning the emission colors of perovskite LEDs.We then move to blue PeLEDs using cesium-based mixed-Br/Cl perovskites. Although mixed halides are a straightforward strategy to tune the emission color, PeLEDs based on this approach suffer from poor color stability, which is attributed to surface defects at grain boundaries. Under the condition of optical excitations, light density over a certain value (a threshold), oxygen, and surface defects at perovskite grain boundaries are found to be key factors inducing photoluminescence (PL) spectral instability of CsPb(Br1−xClx)3 perovskites. Upon electrical bias, defects at grain boundaries provide undesirable halide migration channels, responsible for EL spectral instability issues. Through effective defect passivation, the PL spectral resistance to oxygen is enhanced; moreover, high-performance and color-stable blue PeLEDs are achieved, delivering a maximum luminance of 5351 cd m–2 and a peak EQE of 4.55% with a peak emission wavelength at 489 nm. These findings provide new insights into the color instability issue of mixed halide blue perovskites, against which we also demonstrate an effective strategy.We finally realize single-emissive-layer (EML) white PeLEDs by employing a mixed halide perovskite film as the EML. In spite of high-performance monochromatic blue, green, and red colors, the development of white PeLEDs, especially for single-EML ones, remains a very big challenge. By effective modulation of the halide salt precursors, we achieve single-EML white PeLEDs with Commission Internationale de L’Eclairage (CIE) coordinates of (0.33, 0.33), close to those (0.3128, 0.3290) of the CIE standard illuminant D65. This work not only provides a successful demonstration of a single-EML white PeLED, but also provides useful guidelines for the future development of highperformance single-EML white PeLEDs.
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| 26. |
- Yu, Hongling, et al.
(författare)
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Efficient and Tunable Electroluminescence from In Situ Synthesized Perovskite Quantum Dots
- 2019
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Ingår i: Small. - : WILEY-V C H VERLAG GMBH. - 1613-6810 .- 1613-6829. ; 15:8
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Tidskriftsartikel (refereegranskat)abstract
- Semiconductor quantum dots (QDs) are among the most promising next-generation optoelectronic materials. QDs are generally obtained through either epitaxial or colloidal growth and carry the promise for solution-processed high-performance optoelectronic devices such as light-emitting diodes (LEDs), solar cells, etc. Herein, a straightforward approach to synthesize perovskite QDs and demonstrate their applications in efficient LEDs is reported. The perovskite QDs with controllable crystal sizes and properties are in situ synthesized through one-step spin-coating from perovskite precursor solutions followed by thermal annealing. These perovskite QDs feature size-dependent quantum confinement effect (with readily tunable emissions) and radiative monomolecular recombination. Despite the substantial structural inhomogeneity, the in situ generated perovskite QDs films emit narrow-bandwidth emission and high color stability due to efficient energy transfer between nanostructures that sweeps away the unfavorable disorder effects. Based on these materials, efficient LEDs with external quantum efficiencies up to 11.0% are realized. This makes the technologically appealing in situ approach promising for further development of state-of-the-art LED systems and other optoelectronic devices.
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| 27. |
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| 28. |
- Zhang, Jiangbin, et al.
(författare)
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Efficient non-fullerene organic solar cells employing sequentially deposited donor-acceptor layers
- 2018
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Ingår i: Journal of Materials Chemistry A. - : ROYAL SOC CHEMISTRY. - 2050-7488 .- 2050-7496. ; 6:37, s. 18225-18233
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Tidskriftsartikel (refereegranskat)abstract
- Non-fullerene acceptors (NFAs) have recently outperformed their fullerene counterparts in binary bulk-heterojunction (BHJ) organic solar cells (OSCs). Further development of NFA OSCs may benefit other novel OSC device structures that alter or extend the standard BHJ concept. Here, we report such a new processing route that forms a BHJ-like morphology between sequentially processed polymer donor and NFA with high power conversion efficiencies in excess of 10%. Both devices show similar charge generation and recombination behaviours, supporting formation of similar BHJ active layers. We correlate the approximate to 30 meV smaller open-circuit voltage in sq-BHJ devices to more substantial non-radiative recombination by voltage loss analysis. We also determine the exciton diffusion length of benchmark polymer PBDB-T to be 10 +/- 3 nm. Our results demonstrate high-efficiency OSC devices using sequential deposition method and provide new opportunities to further improve performance of state-of-the-art OSCs.
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