Halogenated thiophene substitutions on quinoxaline unit to achieve morphology optimization in efficient organic solar cells

Halogenated thiophenes are generally used units for constructing organic semiconductor materials for photovoltaic applications.Here,we introduced thiophene,2-bromothiophene,and 2-chlorothiophene units to the central core of quinoxaline-based acceptors and obtained three acceptors,Qx-H,Qx-Br,and Qx-Cl,respectively.Compared with Qx-H,Qx-Br and Qx-Cl showed enhanced absorption,down-shifted energy levels,improved crystallinity,and reduced energy disorder.The improved crystallinity significantly optimized the blend morphology,leading to efficient charge generation and transport and,therefore,less bimolecular recombination.Eventually,PM6:Qx-Br-based devices exhibited an outstanding power conversion efficiency of 17.42%with a high open-circuit voltage(VOC)of 0.915 V.Furthermore,Y6 was introduced into the PM6:Qx-Br binary system to improve the light utilization,and the resulting ternary devices delivered a high PCE of 18.36%.This study demonstrated the great potential of halogenated thiophene substitution in quinoxaline-based acceptors for building high-performance organic solar cell acceptor materials.

Optimization Strategy for Passive Form Design of Architectural Grey Space under the Background of Climate Adaptability

Taking the bottom grey space with great influence on outdoor thermal comfort as the research object,this paper summarizes the morphological characteristics and climate response methods of two types of bottom grey space:overhead grey space and canopy grey space.The spatial form indexes that greatly affect the ecological performance of architectural grey space such as ventilation,shading,etc.are discussed,and two passive spatial form indexes of spatial scale and location orientation are studied.According to the research of related scholars and literature summary,the optimization strategies for passive form design of architectural grey space based on climate adaptability are put forward,which will provide a reference for the climate adaptive design of architectural grey space,and helps to improve the outdoor thermal environment from the micro scale and create a better living environment.

Open critical area model and extraction algorithm based on the net flow-axis

In the integrated circuit manufacturing process, the critical area extraction is a bottleneck to the layout optimization and the integrated circuit yield estimation. In this paper, we study the problem that the missing material defects may result in the open circuit fault. Combining the mathematical morphology theory, we present a new computation model and a novel extraction algorithm for the open critical area based on the net flow-axis. Firstly, we find the net flow-axis for different nets. Then, the net flow-edges based on the net flow-axis are obtained. Finally, we can extract the open critical area by the mathematical morphology. Compared with the existing methods, the nets need not to divide into the horizontal nets and the vertical nets, and the experimental results show that our model and algorithm can accurately extract the size of the open critical area and obtain the location information of the open circuit critical area.

18.01%Efficiency organic solar cell and 2.53%light utilization efficiency semitransparent organic solar cell enabled by optimizing PM6:Y6 active layer morphology

Optimizing the photoactive layer morphology is a simple,promising way to improve the power conversion efficiencies(PCEs)of organic solar cells(OSCs).Here,we compared different post-processing treatments on PM6:Y6 blend films and relevant effects on device performances,including as-cast,thermal annealing and solvent annealing.This solvent annealing processes can effectively improve the vertical distribution and aggregation of polymer donors and small molecule acceptors,then optimize the active layer film morphology,ultimately elevating PCE.Thus,one of champion efficiencies of 18.01%was achieved based on the PM6:Y6 binary OSCs.In addition,a relatively high light utilization efficiency(2.53%)was achieved when a transparent electrode made of Cu(1 nm)and Ag(15 nm)was utilized to fabricate a semitransparent OSC with a remarkable PCE of 13.07%and 19.33%average visible-light transmittance.These results demonstrated that carefully optimizing morphology of active layer is conducive to achieving a high-performance OSC.

Enhancing the performances of all-small-molecule ternary organic solar cells via achieving optimized morphology and 3D charge pathways

With the emergence of non-fullerene acceptors(NFAs),the power conversion efficiencies(PCEs)of allsmall-molecule organic solar cells(ASM-OSCs)have been significantly improved.However,due to the strong crystallinities of small molecules,it is much more challenging to obtain the ideal phase separation morphology and efficient charge transport pathways for ASM-OSCs.Here,a high-efficiency ternary ASMOSC has been successfully constructed based on H11/IDIC-4 F system by introduction of IDIC with a similar backbone as IDIC-4F but weak crystallinity.Notably,the addition of IDIC has effectively suppressed large-scale phase aggregation and optimized the morphology of the blend film.More importantly,the molecular orientation has also been significantly adjusted,and a mixed face-on and edge-on orientation has formed,thus establishing a more favorable three-dimensional(3D)charge pathways in the active layer.With these improvements,the enhanced short-circuit current density(JSC)and fill factor(FF)of the ternary system have been achieved.In addition,because of the high lowest unoccupied molecular orbital(LUMO)energy level of IDIC as well as the alloyed structure of the IDIC and IDIC-4F,the promoted open circuit voltage(VOC)of the ternary system has also been realized.

Ternary organic solar cells:Improved optical and morphological properties allow an enhanced efficiency

The power co nversion efficiency(PCE)of OFQx-T:PC_(71)BM blend films reaches 7.59%.On this basis,ternary organic solar cells(OSCs)were fabricated with ITIC or PTB7-Th as the third component.The ternary OSCs with 50 wt%ITIC in acceptors exhibits an enhanced efficiency,from 7.59%to 8.17%.Also,the PCE of ternary OSCs with 50 wt%PTB7-Th in donors achieves 8.72%,which is 13%higher than that of binary OSCs.The PCE improvement of two ternary OSCs is mainly due to the increase of short-circuit current density(J_(SC)),which can be attributed to the complementary absorption spectra and improved film morphology.This work suggests that the selection of an appropriate third component plays a critical role in improving the PCE of ternary OSCs.