Summary N 6 -methyladenosine (m 6 A), the most prevalent internal RNA modification on mammalian messenger RNAs (mRNAs), regulates fates and functions of modified transcripts through m 6 A-specific binding proteins 1 – 5 . m 6 A is abundant in the nervous system and modulates various neural functions 6 – 11 . While m 6 A marks groups of mRNAs for coordinated degradation in various physiological processes 12 – 15 , the relevance of m 6 A in mRNA translation remains largely unknown in vivo . Here we show that, through its binding protein Ythdf1, m 6 A promotes protein synthesis of target transcripts in response to neuronal stimuli in the adult mouse hippocampus, thereby facilitating learning and memory. Mice with genetic deletion of Ythdf1 ( Ythdf1 -KO) exhibit learning and memory defects as well as impaired hippocampal synaptic transmission and long-term potentiation. Ythdf1 re-expression in the hippocampus of adult Ythdf1 -KO mice rescues behavioral and synaptic defects, while hippocampus-specific acute knockdown of Ythdf1 or Mettl3 , the catalytic component of m 6 A methyltransferase complex, recapitulates the hippocampal deficiency. Transcriptome-wide mapping of Ythdf1 binding sites and m 6 A sites on hippocampal mRNAs uncovered key neuronal genes. Nascent protein labeling and tether reporter assays in hippocampal neurons revealed that Ythdf1 enhances protein synthesis in a neuronal-stimulus-dependent manner. Collectively, our results uncover a pathway of mRNA m 6 A methylation in learning and memory, which is mediated through Ythdf1 in response to stimuli.

During the past decade, inorganic CQDs, namely the lead chalcogenides (e.g., PbS), have attracted tremendous attention in solution-processed solar cells. Due to the great efforts on CQDs synthesis modification, [7][8][9] surface passivation, [10][11][12] and device fabrication optimization, [13][14][15][16] PbS QD solar cells continue to progress at an extraordinary rate, improving overall efficiencies by ≈1% per year and currently have a certified power conversion efficiency (PCE) exceeding 12%. [17] Meanwhile, the past decade has witnessed unprecedented success of organicinorganic hybrid perovskites in PV applications, with the reported PCE of perovskite solar cells exceeding 23%. [18][19][20][21][22][23][24][25][26][27][28] However, the challenging stability issues of these hybrid perovskites further motivate the research of all-inorganic perovskites (CsPbX 3 , X = Cl − , Br − , I − or mixed halides) without any volatile organic components. [29][30][31][32][33][34][35][36][37][38] Among these all-inorganic perovskite materials, α-CsPbI 3 exhibits an ideal optical bandgap (E g ) of 1.73 eV for PV applications. However, the nonphotoactive orthorhombic phase (E g = 2.82 eV) is more thermodynamically preferred at low temperature. [29] Therefore, the perovskite phase of CsPbI 3 usually requires complex annealing processes at high temperature to achieve satisfactory film quality. As mentioned above, QD technology offers colloidal synthesis of conventional bulk materials, which Surface manipulation of quantum dots (QDs) has been extensively reported to be crucial to their performance when applied into optoelectronic devices, especially for photovoltaic devices. In this work, an efficient surface passivation method for emerging CsPbI 3 perovskite QDs using a variety of inorganic cesium salts (cesium acetate (CsAc), cesium idodide (CsI), cesium carbonate (Cs 2 CO 3 ), and cesium nitrate (CsNO 3 )) is reported. The Cs-salts post-treatment can not only fill the vacancy at the CsPbI 3 perovskite surface but also improve electron coupling between CsPbI 3 QDs. As a result, the free carrier lifetime, diffusion length, and mobility of QD film are simultaneously improved, which are beneficial for fabricating high-quality conductive QD films for efficient solar cell devices. After optimizing the post-treatment process, the short-circuit current density and fill factor are significantly enhanced, delivering an impressive efficiency of 14.10% for CsPbI 3 QD solar cells. In addition, the Cs-salt-treated CsPbI 3 QD devices exhibit improved stability against moisture due to the improved surface environment of these QDs. These findings will provide insight into the design of high-performance and low-trap-states perovskite QD films with desirable optoelectronic properties. Perovskite Quantum DotsThe ORCID identification number(s) for the author(s) of this article can be found under https://doi.Solution-processed colloidal quantum dots (CQDs) are promising candidates for the next generation photovoltaics (PVs) due to the excellent tuna...

A ligand-assisted matrix to regulate surface and packing states of perovskite quantum dots (QDs) is demonstrated, which involves a ligand exchange and a mild thermal annealing process that are triggered by guanidinium thiocyanate. Consequently, the CsPbI 3 QD solar cells (QDSCs) deliver a champion power conversion efficiency of 15.21%, which is the highest report among all CsPbI 3 QDSCs.

Lead halide perovskite quantum dots (PQDs) or more broadly, nanocrystals possess advantageous features for solution-processed photovoltaic devices. The nanocrystal surface ligands play a crucial role in the transport of photogenerated carriers and ultimately affect the overall performance of PQD solar cells. We have demonstrated significantly improved CsPbI 3 PQD synthetic yield and solar cells performance through surface ligand management. The treatment of a secondary amine, di-n-propylamine (DPA), provides a mild and efficient approach to control the surfaces ligand density of PQDs, which has apparently different working mechanism compared to the previously reported surface treatment. Using an optimal DPA concentration, the treatment can simultaneously remove both long chain insulating surface ligands of oleic acid and oleylamine, even for unpurified This article is protected by copyright. All rights reserved.PQDs with high ligand density. As a result, the electrical coupling between PQDs is enhanced; leading to improved charge transport, reduced carrier recombination, and a high power conversion efficiency (PCE) approaching 15% for CsPbI 3 PQD based solar cells. In addition, the production yield of CsPbI 3 PQDs can be increased by a factor of 8. These results highlight the importance of developing new ligand-management strategies, specifically for emerging PQDs to achieve scalable and high-performance perovskite-based optoelectronic devices.All-inorganic perovskite quantum dots (PQDs) exhibit high photoluminescence quantum yields (PLQY), spectrally tunable bandgap, flexible compositional control, and crystalline strain benefits. [1][2][3][4] PQDs are relatively easy to synthesize which opens a route for next generation optoelectronic devices, as well as opportunities for exploring fundamental properties at nanoscale. [5,6] For photovoltaics (PVs), colloidal CsPbI 3 PQD solar cells were first demonstrated with a power