- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
COMPARISON OF PERFORMANCES OF ORGANIC PHOTOVOLTAIC CELLS USING SubPc AS CENTRAL AMBIPOLAR LAYER IN TERNARY STRUCTURES AND AS ELECTRON ACCEPTOR IN BINARY STRUCTURES
摘要： We compare the performances of organic photovoltaic cells (OPVCs) based on binary and ternary planar heterojunctions. The organic active layers are pentathiophene (5T), subphthalocyanine (SubPc) and fullerene (C60). SubPc being an ambipolar material we used it either as electron acceptor in binary OPVCs or as central layer in ternary cells in order to increase the efficiency of OPVCs using 5T as electron donor. So, the different OPVC configurations were 5T/C60, 5T/SubPc and 5T/SubPc/C60. The effect of the different organic layer thicknesses on the device performances was studied. In order to understand the behavior of the different OPVC configurations, we proceeded with a morphological study. The influence of the high roughness of the 5T layer on the OPVCs performances is discussed. The best OPVCs performances are obtained with the binary structure 5T/SubPc. Its maximum efficiency corresponds to an increase of 50% compared to the OPVC based on the couple 5T/C60. External Quantum Efficiency measurements show that both layers participate to the current generation. The efficiency increase is mainly due to the increase of the open circuit voltage (Voc). In the case of ternary OPVCs, Voc is limited by the band structure of 5T and C60, moreover, the efficiency is also limited by the poor charge collection efficiency of the ternary structure and the series resistance of the three stacked organic layers.
关键词： Organic photovoltaic cells,ternary structures,pentathiophene,subphthalocyanine,binary structures
更新于2025-09-19 17:13:59
-
Molecular Recognition and Band Alignment in 3D Covalent Organic Frameworks for Cocrystalline Organic Photovoltaics
摘要： Covalent organic frameworks (COFs) have emerged as versatile, functional materials comprised of low-cost molecular building blocks. The permanent porosity, long-range order, and high surface area of 3D-COFs permit co-crystallization with other materials driven by supramolecular interactions. We designed a new subphthalocyanine-based 3-D covalent organic framework (NEUCOF1) capable of forming co-crystals with fullerene (C60) via periodic ball-and-socket binding motifs. The high co-crystalline surface area and long-range order of NEUCOF1 eliminates the typical surface area vs. structural order trade-off in organic photovoltaics (OPVs). We used plane-wave density functional theory (PBE) to minimize NEUCOF1 and NEUCOF1–C60 co-crystals and determine their electronic band structures. Molecular dynamics (MD) simulations showed that dispersive interactions promoting co-crystallinity NEUCOF1–C60 are stable up to 350 K. The band structures at 0 and 350 K suggest that there is a driving force of 0.27 eV for exciton charge transfer to the pocket-bound fullerenes. Charge separation could then occur at the COF-C60 D-A interface, followed by the transfer of the free electron to the nanowire of C60 acceptors with a driving force of 0.20 eV.
关键词： fullerene,subphthalocyanine,co-crystallization,density functional theory,molecular dynamics,Covalent organic frameworks,organic photovoltaics
更新于2025-09-19 17:13:59