Optimizing the molecular structures of organic photovoltaic (OPV) materials is one of the most effective methods to boost power conversion efficiencies (PCEs). For an excellent molecular system with a certain conjugated skeleton, fine tuning the alky chains is of considerable significance to fully explore its photovoltaic potential. In this work, the optimization of alkyl chains is performed on a chlorinated nonfullerene acceptor (NFA) named BTP-4Cl-BO (a Y6 derivative) and very impressive photovoltaic parameters in OPV cells are obtained. To get more ordered intermolecular packing, the n-undecyl is shortened at the edge of BTP-eC11 to n-nonyl and n-heptyl. As a result, the NFAs of BTP-eC9 and BTP-eC7 are synthesized. The BTP-eC7 shows relatively poor solubility and thus limits its application in device fabrication. Fortunately, the BTP-eC9 possesses good solubility and, at the same time, enhanced electron transport property than BTP-eC11. Significantly, due to the simultaneously enhanced short-circuit current density and fill factor, the BTP-eC9-based single-junction OPV cells record a maximum PCE of 17.8% and get a certified value of 17.3%. These results demonstrate that minimizing the alkyl chains to get suitable solubility and enhanced intermolecular packing has a great potential in further improving its photovoltaic performance.

Single-Junction Organic Photovoltaic Cells with Approaching 18% Efficiency.

Obtaining a finely tuned morphology of the active layer to facilitate both charge generation and charge extraction has long been the goal in the field of organic photovoltaics (OPVs). Here, a solution to resolve the above challenge via synergistically combining the layer-by-layer (LbL) procedure and the ternary strategy is proposed and demonstrated. By adding an asymmetric electron acceptor, BTP-S2, with lower miscibility to the binary donor:acceptor host of PM6:BO-4Cl, vertical phase distribution can be formed with donor-enrichment at the anode and acceptor-enrichment at the cathode in OPV devices during the LbL processing. In contrast, LbL-type binary OPVs based on PM6:BO-4Cl still show bulk-heterojunction like morphology. The formation of the vertical phase distribution can not only reduce charge recombination but also promote charge collection, thus enhancing the photocurrent and fill factor in LbL-type ternary OPVs. Consequently, LbL-type ternary OPVs exhibit the best efficiency of 18.16% (certified: 17.8%), which is among the highest values reported to date for OPVs. The work provides a facile and effective approach for achieving high-efficiency OPVs with expected morphologies, and demonstrates the LbL-type ternary strategy as being a promising procedure in fabricating OPV devices from the present laboratory study to future industrial production.

Layer-by-Layer Processed Ternary Organic Photovoltaics with Efficiency over 18.

The use of photovoltaic technologies has been regarded as a promising approach for converting solar energy to electricity and mitigating the energy crisis, and among these, organic photovoltaics (O...

n-Type Molecular Photovoltaic Materials: Design Strategies and Device Applications.

https://www.cell.com/joule/pdfExtended/S2542-4351(20)30346-9

Single-Component Non-halogen Solvent-Processed High-Performance Organic Solar Cell Module with Efficiency over 14%

Great progress in organic solar cells (OSCs) has been recently achieved owing to the advent of non-fullerene acceptors (NFAs). Indeed, low-bandgap NFAs ranging from 1.3 to 1.6 eV with broad absorpt...

Low-Bandgap Non-fullerene Acceptors Enabling High-Performance Organic Solar Cells

Processing Strategies for an Organic Photovoltaic Module with over 10% Efficiency

Loop closure detection (LCD) can effectively eliminate the cumulative errors in simultaneous localization and mapping (SLAM) by detecting the position of a revisit and building interframe pose constraint relations. However, in real-world natural scenes, driverless ground vehicles or robots usually revisit the same place from a different position, meaning that the descriptor cannot give a uniform description of similar scenes, failing LCD. Against this problem, this paper proposes a 3D point cloud descriptor with Twice Projection (3PCD-TP) for the calculation of the similarities between scenes. First, we redefined the origin and primary direction of point clouds according to their distribution and unified their coordinate system, thereby reducing the interference in position recognition due to the rotation and translation of sensors. Next, using the semantic and altitudinal information of point clouds, we generated the 3D descriptor 3PCD-TP with multidimensional features to enhance its ability to describe similar scenes. Following this, we designed a weighting similarity calculation method to reduce the false detection rate of LCD by taking advantage of the property that 3PCD-TP can be projected from multiple angles. Finally, we validated our method using KITTI and the Jilin University (JLU) campus dataset. The experimental results show that our method demonstrated a high level of precision and recall and exhibited greater performance in the face of scenes with reverse loop closure, such as opposite lanes.

/pdf/3pcd-tp-a-3d-point-cloud-descriptor-for-loop-closure-28h1ac00.pdf

3PCD-TP: A 3D Point Cloud Descriptor for Loop Closure Detection with Twice Projection

Simultaneous localization and mapping (SLAM) algorithm is a prerequisite for unmanned ground vehicle (UGV) localization, path planning, and navigation, which includes two essential components: frontend odometry and backend optimization. Frontend odometry tends to amplify the cumulative error continuously, leading to ghosting and drifting on the mapping results. However, loop closure detection (LCD) can be used to address this technical issue by significantly eliminating the cumulative error. The existing LCD methods decide whether a loop exists by constructing local or global descriptors and calculating the similarity between descriptors, which attaches great importance to the design of discriminative descriptors and effective similarity measurement mechanisms. In this paper, we first propose novel multi-channel descriptors (CMCD) to alleviate the lack of point cloud single information in the discriminative power of scene description. The distance, height, and intensity information of the point cloud is encoded into three independent channels of the shadow-casting region (bin) and then compressed it into a two-dimensional global descriptor. Next, an ORB-based dynamic threshold feature extraction algorithm (DTORB) is designed using objective 2D descriptors to describe the distributions of global and local point clouds. Then, a DTORB-based similarity measurement method is designed using the rotation-invariance and visualization characteristic of descriptor features to overcome the subjective tendency of the constant threshold ORB algorithm in descriptor feature extraction. Finally, verification is performed over KITTI odometry sequences and the campus datasets of Jilin University collected by us. The experimental results demonstrate the superior performance of our method to the state-of-the-art approaches.

/pdf/a-multi-channel-descriptor-for-lidar-based-loop-closure-2zkj5cy3.pdf

A Multi-Channel Descriptor for LiDAR-Based Loop Closure Detection and Its Application

ABSTRACT Objectives The current study aimed to explore the incidence of MPL mutations and the clinical and molecular characteristics of AML with MPL mutation. Methods In total, 1509 patients with newly diagnosed AML were retrospectively analyzed between January 2017 and December 2020. MPL mutations were detected via next-generation sequencing. During the same period, we also enrolled 30 patients with other myeloid neoplasms (MNs) with MPL mutation, which included myelodysplastic syndrome (n = 15), myelodysplastic syndrome/myeloproliferative neoplasm (MDS/MPN) (n = 6), and MPN (n = 9). The clinical characteristics of MPL-mutated AML and other types of MNs or MPL-wide type (MPL-wt) AML were compared, and the spectrum of co-mutations and MPL mutation profiles in MPL-mutated AML were analyzed. Results MPL mutations were identified in 19 (1.26%) of 1509 patients with AML. The waterfall diagram showed that the co-mutations were mainly epigenetic modifications (TET2, IDH1, and EZH2), spliceosomes (SRSF2), and transcription factors (RUNX1). The platelet count of the AML group was significantly lower than that of the MPN group (p = 0.001). MPL mutations were commonly observed in the intracellular region in AML but the transmembrane region in MPN (p = 0.013). The MPL-mutated AML group had a lower white blood cell count and a lower rate of complete remission than the MPL wild-type AML group (p = 0.037). Conclusion MPL mutations are clinically relevant in patients with AML, and they may be a novel subtype characterized by lower white blood cell counts and poor complete remission rates. However, further studies must be conducted to identify its correlated mechanism.

https://doi.org/10.1080/16078454.2022.2066244

Yu Kuang Chen

Papers

Processing Strategies for an Organic Photovoltaic Module with over 10% Efficiency

3PCD-TP: A 3D Point Cloud Descriptor for Loop Closure Detection with Twice Projection

A Multi-Channel Descriptor for LiDAR-Based Loop Closure Detection and Its Application

Clinical and molecular characteristics of acute myeloid leukemia with MPL mutation