Maskless fabrication of quasi-omnidirectional V-groove solar cells using an alkaline solution-based method

Silicon passivated emitter and rear contact(PERC) solar cells with V-groove texture were fabricated using maskless alkaline solution etching with in-house developed additive. Compared with the traditional pyramid texture, the V-groove texture possesses superior effective minority carrier lifetime, enhanced p–n junction quality and better applied filling factor(FF). In addition, a V-groove texture can greatly reduce the shading area and edge damage of front Ag electrodes when the V-groove direction is parallel to the gridline electrodes. Due to these factors, the V-groove solar cells have a higher efficiency(21.78%) than pyramid solar cells(21.62%). Interestingly, external quantum efficiency(EQE) and reflectance of the V-groove solar cells exhibit a slight decrease when the incident light angle(θ) is increased from 0° to 75°, which confirms the excellent quasi omnidirectionality of the V-groove solar cells. The proposed V-groove solar cell design shows a 2.84% relative enhancement of energy output over traditional pyramid solar cells.

Four-inch high quality crack-free AlN layer grown on a hightemperature annealed AlN template by MOCVD

In this work,based on physical vapor deposition and high-temperature annealing(HTA),the 4-inch crack-free high-quality AlN template is initialized.Benefiting from the crystal recrystallization during the HTA process,the FWHMs of X-ray rocking curves for(002)and(102)planes are encouragingly decreased to 62 and 282 arcsec,respectively.On such an AlN template,an ultra-thin AlN with a thickness of~700 nm grown by MOCVD shows good quality,thus avoiding the epitaxial lateral over-growth(ELOG)process in which 3-4μm AlN is essential to obtain the flat surface and high crystalline quality.The 4-inch scaled wafer provides an avenue to match UVC-LED with the fabrication process of traditional GaN-based blue LED,therefore significantly improving yields and decreasing cost.

Enhanced YOLOv5 network-based object detection(BALFilter Reader)promotes PERFECT filter-enabled liquid biopsy of lung cancer from bronchoalveolar lavage fluid(BALF)

Liquid biopsy of cancers,detecting tumor-related information from liquid samples,has attracted wide attentions as an emerging technology.Our previously reported large-area PERFECT(Precise-Efficient-Robust-Flexible-Easy-ControllableThin)filter has demonstrated competitive sensitivity in recovering rare tumor cells from clinical samples.However,it is time-consuming and easily biased to manually inspect rare target cells among numerous background cells distributed in a large area(Φ≥13 mm).This puts forward an urgent demand for rapid and bias-free inspection.Hereby,this paper implemented deep learning-based object detection for the inspection of rare tumor cells from large-field images of PERFECT filters with hematoxylin-eosin(HE)-stained cells recovered from bronchoalveolar lavage fluid(BALF).CenterNet,EfficientDet,and YOLOv5 were trained and validated with 240 and 60 image blocks containing tumor and/or background cells,respectively.YOLOv5 was selected as the basic network given the highest mAP@0.5 of 92.1%,compared to those of CenterNet and EfficientDet at 85.2%and 91.6%,respectively.Then,tricks including CIoU loss,image flip,mosaic,HSV augmentation and TTA were applied to enhance the performance of the YOLOv5 network,improving mAP@0.5 to 96.2%.This enhanced YOLOv5 network-based object detection,named as BALFilter Reader,was tested and cross-validated on 24 clinical cases.The overall diagnosis performance(~2 min)with sensitivity@66.7%±16.7%,specificity@100.0%±0.0%and accuracy@75.0%±12.5%was superior to that from two experienced pathologists(10–30 min)with sensitivity@61.1%,specificity@16.7%and accuracy@50.0%,with the histopathological result as the gold standard.The AUC of the BALFilter Reader is 0.84±0.08.Moreover,a customized Web was developed for a user-friendly interface and the promotion of wide applications.The current results revealed that the developed BALFilter Reader is a rapid,bias-free and easily accessible AI-enabled tool to promote the transplantation of the BALFilter technique.This work can easily expand to other cytopathological diagnoses and improve the application value of micro/nanotechnology-based liquid biopsy in the era of intelligent pathology.

2.5-Dimensional Parylene C micropore array with a large area and a high porosity for high-throughput particle and cell separation

Large-area micropore arrays with a high porosity are in high demand because of their promising potential in liquid biopsy with a large volume of clinical sample.However,a micropore array with a large area and a high porosity faces a serious mechanical strength challenge.The filtration membrane may undergo large deformation at a high filtration throughput,which will decrease its size separation accuracy.In this work,a keyhole-free Parylene molding process has been developed to prepare a large(>20 mm×20 mm)filtration membrane containing a 2.5-dimensional(2.5D)micropore array with an ultra-high porosity(up to 91.37% with designed pore diameter/space of 100μm/4μm).The notation 2.5D indicates that the large area and the relatively small thickness(approximately 10μm)of the fabricated membranes represent 2D properties,while the large thickness-to-width ratio(10μm/<4μm)of the spaces between the adjacent pores corresponds to a local 3D feature.The large area and high porosity of the micropore array achieved filtration with a throughput up to 180 mL/min(PBS solution)simply driven by gravity.Meanwhile,the high mechanical strength,benefiting from the 2.5D structure of the micropore array,ensured a negligible pore size variation during the high-throughput filtration,thereby enabling high size resolution separation,which was proven by single-layer and multi-layer filtrations for particle separation.Furthermore,as a preliminary demonstration,the prepared 2.5-dimensional Parylene C micropore array was implemented as an efficient filter for rare cancer cell separation from a large volume,approximately 10 cells in 10 mL PBS and undiluted urine,with high recovery rates of 87±13% and 56±13%,respectively.

A micropore array-based solid lift-off method for highly efficient and controllable cell alignment and spreading

Interpretation of cell–cell and cell-microenvironment interactions is critical for both advancing knowledge of basic biology and promoting applications of regenerative medicine.Cell patterning has been widely investigated in previous studies.However,the reported methods cannot simultaneously realize precise control of cell alignment and adhesion/spreading with a high efficiency at a high throughput.Here,a novel solid lift-off method with a micropore array as a shadow mask was proposed.Efficient and precise control of cell alignment and adhesion/spreading are simultaneously achieved via an ingeniously designed shadow mask,which contains large micropores(capture pores)in central areas and small micropores(spreading pores)in surrounding areas contributing to capture/alignment and adhesion/spreading control,respectively.The solid lift-off functions as follows:(1)protein micropattern generates through both the capture and spreading pores,(2)cell capture/alignment control is realized through the capture pores,and(3)cell adhesion/spreading is controlled through previously generated protein micropatterns after lift-off of the shadow mask.High-throughput(2.4–3.2×10^(4) cells/cm 2)cell alignments were achieved with high efficiencies(86.2±3.2%,56.7±9.4%and 51.1±4.0%for single-cell,double-cell,and triple-cell alignments,respectively).Precise control of cell spreading and applications for regulating cell skeletons and cell–cell junctions were investigated and verified using murine skeletal muscle myoblasts.To the best of our knowledge,this is the first report to demonstrate highly efficient and controllable multicell alignment and adhesion/spreading simultaneously via a simple solid lift-off operation.This study successfully fills a gap in literatures and promotes the effective and reproducible application of cell patterning in the fields of both basic mechanism studies and applied medicine.