In this study, organic solar cells (OSCs) with an active layer, a blend of polymer of non-fullerene (NFA) Y6 as an acceptor, and donor PBDB-T-2F as donor were simulated through the one-dimensional solar capacitance si...In this study, organic solar cells (OSCs) with an active layer, a blend of polymer of non-fullerene (NFA) Y6 as an acceptor, and donor PBDB-T-2F as donor were simulated through the one-dimensional solar capacitance simulator (SCAPS-1D) software to examine the performance of this type of organic polymer thin-film solar cell by varying the thickness of the active layer. PFN-Br interfacial layer entrenched in OPV devices gives overall enhanced open-circuit voltage, short-circuit current density and fill factor thus improving device performance. PEDOT: PSS is an electro-conductive polymer solution that has been extensively utilized in solar cell devices as a hole transport layer (HTL) due to its strong hole affinity, good thermal and mechanical stability, high work function, and high transparency in the visible range. The structure of the organic solar cell is ITO/PEDOT: PSS/BTP-4F: PBDB-T-2F/PFN-Br/Ag. Firstly, the active layer thickness was optimized to 100 nm;after that, the active-layer thickness was varied up to 900 nm. The results of these simulations demonstrated that the active layer thickness improves efficiency significantly up to 500 nm, then it decreased with increasing the thickness of the active layer from 600 nm, also notice that the short circuit current and the fill factor decrease with increasing the active layer from 600 nm, while the open voltage circuit increased with increasing the thickness of the active layer. The optimum thickness is 500 nm.展开更多
Conjugated polymers are widely used in organic optoelectronic devices due to their solution processability, thermal stability and structural diversity. Generally, alkyl side chains must be utilized to increase the sol...Conjugated polymers are widely used in organic optoelectronic devices due to their solution processability, thermal stability and structural diversity. Generally, alkyl side chains must be utilized to increase the solubility of final polymers in the processing solvent. However, the effects of different type alkyl chains on the properties of n-type photovoltaic polymers have rarely been investigated. In this article, we synthesized three naphthodithiophene diimide（NDTI） based polymers containing bulky alkyl chains with different branching position, named as NDTI-1, NDTI-2 and NDTI-3, respectively. We systematically investigated the effect of different branching point on the molecular packing, charge transport and photovoltaic performance. When moving the branching point away from the backbone, the intermolecular interaction became stronger, which could be proved by 2D grazing incidence wide angle X-ray scattering（GIWAXS） measurement. Therefore, the electron mobilities in organic field-effect transistors gradually increased from 2.11×10-3 cm2 V/-1 s-1 for NDTI-1 to 4.70×10-2 cm2 V/-1 s-1 for NDTI-2 and 9.27×10-2 cm2 V/-1 s-1 for NDTI-3,which are quite high values for polymers with face-on orientation. In addition, the NDTI-2 and NDTI-3 thin films exhibited redshifted absorption spectra compared with NDTI-1. When blending with three classic donor polymers PBDB-T, PTB7-Th and PE61, NDTI-2 based devices always showed the higher power conversion efficiencies（PCEs） than the other two polymers（beside the comparable result of PTB7-Th:NDTI-3 combination） as a result of the high photocurrent response and high fill factor. Our results indicate that bulky alkyl chain with branching point at 2-position should be a good and safe choice for the design of naphthodithiophene diimide-based and even naphthalene diimide-based n-type photovoltaic polymers.展开更多
文摘In this study, organic solar cells (OSCs) with an active layer, a blend of polymer of non-fullerene (NFA) Y6 as an acceptor, and donor PBDB-T-2F as donor were simulated through the one-dimensional solar capacitance simulator (SCAPS-1D) software to examine the performance of this type of organic polymer thin-film solar cell by varying the thickness of the active layer. PFN-Br interfacial layer entrenched in OPV devices gives overall enhanced open-circuit voltage, short-circuit current density and fill factor thus improving device performance. PEDOT: PSS is an electro-conductive polymer solution that has been extensively utilized in solar cell devices as a hole transport layer (HTL) due to its strong hole affinity, good thermal and mechanical stability, high work function, and high transparency in the visible range. The structure of the organic solar cell is ITO/PEDOT: PSS/BTP-4F: PBDB-T-2F/PFN-Br/Ag. Firstly, the active layer thickness was optimized to 100 nm;after that, the active-layer thickness was varied up to 900 nm. The results of these simulations demonstrated that the active layer thickness improves efficiency significantly up to 500 nm, then it decreased with increasing the thickness of the active layer from 600 nm, also notice that the short circuit current and the fill factor decrease with increasing the active layer from 600 nm, while the open voltage circuit increased with increasing the thickness of the active layer. The optimum thickness is 500 nm.
基金supported by the National Key Research and Development Program of China (2017YFA0206600)the Key Research Program of Frontier Sciences, Chinese Academy of Sciences (QYZDB-SSW-SLH033)the National Natural Science Foundation of China (51673048, 21875052)
文摘Conjugated polymers are widely used in organic optoelectronic devices due to their solution processability, thermal stability and structural diversity. Generally, alkyl side chains must be utilized to increase the solubility of final polymers in the processing solvent. However, the effects of different type alkyl chains on the properties of n-type photovoltaic polymers have rarely been investigated. In this article, we synthesized three naphthodithiophene diimide（NDTI） based polymers containing bulky alkyl chains with different branching position, named as NDTI-1, NDTI-2 and NDTI-3, respectively. We systematically investigated the effect of different branching point on the molecular packing, charge transport and photovoltaic performance. When moving the branching point away from the backbone, the intermolecular interaction became stronger, which could be proved by 2D grazing incidence wide angle X-ray scattering（GIWAXS） measurement. Therefore, the electron mobilities in organic field-effect transistors gradually increased from 2.11×10-3 cm2 V/-1 s-1 for NDTI-1 to 4.70×10-2 cm2 V/-1 s-1 for NDTI-2 and 9.27×10-2 cm2 V/-1 s-1 for NDTI-3,which are quite high values for polymers with face-on orientation. In addition, the NDTI-2 and NDTI-3 thin films exhibited redshifted absorption spectra compared with NDTI-1. When blending with three classic donor polymers PBDB-T, PTB7-Th and PE61, NDTI-2 based devices always showed the higher power conversion efficiencies（PCEs） than the other two polymers（beside the comparable result of PTB7-Th:NDTI-3 combination） as a result of the high photocurrent response and high fill factor. Our results indicate that bulky alkyl chain with branching point at 2-position should be a good and safe choice for the design of naphthodithiophene diimide-based and even naphthalene diimide-based n-type photovoltaic polymers.
