Search

The power conversion efficiency (PCE) of perovskite solar cells (PSCs) is approaching their Shockley‐Queisser (S‐Q) limit through numerous efforts in key parameters improvement. To further approaching the limit, it is important to facilitate the fill factor (FF), a parameter closely related to carrier transport and nonradiative recombination. Herein, an interfacial bridging strategy is proposed to improve FF, which utilizes functional graphene quantum dots at the tin oxide (SnO2)/perovskite buried interface. As a result, synergistic effects of enhanced conductivity of SnO2, preferable energy alignment at the buried interface and improved perovskite crystal orientation are realized. The champion FF reaches 85.24% in formamidinium lead iodide (FAPbI3) based PSCs, which ranks among the highest in the n‐i‐p structure. Such strategy is also proven successful in other perovskite systems, where the champion PCE reaches 24.86% in the formamidinium‐cesium (FACs)‐based devices and 24.44% in the flexible devices. Therefore, this work provides a practical design rule for pursuing high FF of PSCs with carbon materials. [ABSTRACT FROM AUTHOR]

The fragile bottom side of perovskite films is demonstrated to be harmful to the efficiency and stability of perovskite solar cells (PSCs) because the carrier extraction and recombination can be significantly influenced by the easily formed strain, voids, and defects on the bottom side. Nevertheless, the bottom side of perovskite films is usually overlooked because it remains a challenge to directly characterize and modify the bottom side. Herein, a facile and effective strategy is reported to stabilize the bottom side via preburying cesium formate (CsFo) into the SnO2 electron transport layer (ETL). It is found that the synergistic effect of cesium cation (Cs+) and formate anion (HCOO−) causes strain relaxation, void elimination, and defects' reduction, which further facilitate the charge extraction. Consequently, the champion power conversion efficiency (PCE) of formamidinium (FA)‐based PSCs is increased from 23.34% to 24.50%. Meanwhile, the ultraviolet (UV), thermal, and operational stability are also enhanced. Finally, formamidinium–cesium (FACs)‐based PSCs are investigated to confirm the effectiveness of this preburied CsFo strategy, and the optimal device exhibits a champion PCE of 25.03% and a remarkably high fill factor (FF) of 85.65%. [ABSTRACT FROM AUTHOR]

2D Ruddlesden–Popper perovskites have attracted increasing attention for their outstanding optoelectronic properties and improved stability compared to the 3D counterparts. The unique nature of the crystal growth orientations and the uneven distribution in the 2D perovskites provide a great opportunity to construct a promising lateral photodetector device that has not been fully uncovered. Here, by improving the random orientation to the vertical orientation of the film in the lateral device structure, the dark current is expected to be significantly suppressed in the photodetector. Accompanied by the gradient phase distribution, a p‐type conductive channel at the bottom and another electron collection layer on the top are applied to achieve a high on/off ratio. Overall, the resultant photodetector realizes a low dark current of 10−10 A and exhibits impressive photodetection performance, including a high responsivity of 10.10 A W−1, a notable detectivity of 6.83 × 1012 Jones, and fast response speeds (14 ms/31 ms). [ABSTRACT FROM AUTHOR]

Constitutive activation of FGFR1, as a result of diverse chromosome translocations, is the hallmark of stem cell leukemia/lymphoma syndrome. The BCR‐FGFR1 variant is unique in that the BCR component contributes a serine–threonine kinase (STK) to the N‐terminal end of the chimeric FGFR1 kinase. We have deleted the STK domain and mutated the critical Y177 residue and demonstrate that the transforming activity of these mutated genes is reduced compared to the BCR‐FGFR1 parental kinase. In addition, we demonstrate that deletion of the FGFR1 tyrosine kinase domain abrogates transforming ability, which is not compensated for by BCR STK activity. Unbiased screening for proteins that are inactivated as a result of loss of the BCR STK identified activated S6 kinase and SHP2 kinase. Genetic and pharmacological inhibition of SHP2 function in SCLL cells expressing BCR‐FGFR1 in vitro leads to reduced viability and increased apoptosis. In vivo treatment of SCLL in mice with SHP099 leads to suppression of leukemogenesis, supporting an important role for SHP2 in FGFR1‐driven leukemogenesis. In combination with the BGJ398 FGFR1 inhibitor, cell viability in vitro is further suppressed and acts synergistically with SHP099 in vivo suggesting a potential combined targeted therapy option in this subtype of SCLL disease. What's new? Constitutive activation of FGFR1 tyrosine kinase, as a result of diverse chromosome translocations, is the hallmark of stem cell leukemia/lymphoma syndrome. The relative contribution of the fusion partner genes remains unclear, however. Here, the authors show that the BCR gene serine–threonine kinase can modify disease course in vivo, through activation of SHP2 and its downstream targets. Pharmacologically targeting both SHP2 and FGFR1 displays synergistic efficacy in treating BCR‐FGFR1 disease subtype. The study indicates the potential role of fusion partner genes in modifying disease phenotype and rationalizes the need for precision therapeutics that target activation of both FGFR1 and fusion partners. [ABSTRACT FROM AUTHOR]

Ufmylation was proved to play a crucial role in hematopoietic stem cell (HSC) survival and erythroid differentiation, ufmylation deficiency induces acute anemia and lethality of embryos and adults in mouse models. To screen some compounds to rescue phenotypes induced by gene deletion, in this study, we used DDRGK1F/F; CreERT2 conditional knockout mice, DDRGK1F/F; CreERT2 bone marrow (BM) and fetal liver cells (FL), Uba5, and DDRGK1 knockdown human CD34 cell in vivo and in vitro, we found salubrinal, a novel inhibitor of eIF‐2α dephosphorylation, promoted erythropoiesis at early stage, and partly rescued the acute anemia induce by DDRGK1 deficiency through upregulation of ufmylation and erythroid transcription factors. In phenylhydrazine (PHZ)‐induced hemolytic anemia mice, interestingly, salubrinal could significantly improve hemocrit and red blood cell (RBC) indices of the mice treated with PHZ via upregulation of ufmylation. Its novel function was verified to attenuate unfolded protein response (UPR) and cell death programs, and to keep endoplasmic reticulum (ER) homeostasis in HSCs. Taken together results, it suggested that salubrinal may be a promising antianemic agent targeted by ufmylation. [ABSTRACT FROM AUTHOR]

Stem cell leukemia/lymphoma syndrome (SCLL) is driven by constitutive activation of chimeric FGFR1 kinases generated by chromosome translocations. We have shown that FGFR inhibitors significantly suppress leukemia and lymphoma development in vivo, and cell viability in vitro. Since resistance to targeted therapies is a major reason for relapse, we developed FGFR1-overexpressing mouse and human cell lines that are resistant to the specific FGFR inhibitors AZD4547 and BGJ398, as well as non-specific inhibitors, such as ponatinib, TKI258 and E3810. Two mutually exclusive mechanisms for resistance were demonstrated; an activating V561M mutation in the FGFR1 kinase domain and mutational inactivation of PTEN resulting in increased PI3K/AKT activity. Ectopic expression of PTEN in the PTEN-mutant cells resensitizes them to FGFR inhibitors. Treatment of resistant cells with BGJ398, in combination with the BEZ235 PI3K inhibitor, shows an additive effect on growth in vitro and prolongs survival in xenograft models in vivo. These studies provide the first direct evidence for both the involvement of the FGFR1 V561M mutation and PTEN inactivation in the development of resistance in leukemias overexpressing chimeric FGFR1. These studies also provide a potential strategy to treat leukemias and lymphomas driven by FGFR1 activation that become resistant to FGFR1 inhibitors. [ABSTRACT FROM AUTHOR]