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New energetic indandione based planar donor for stable and efficient organic solar cells
摘要： The present work documents the synthesis of a new and highly energetic indandione based D-π-A planar molecule, 2-(5″-hexyl-[2,2′:5′2″ terthiophen]-5-yl) methylene)-1H- indene-1,3(2H) dione, H3T-ID), as donor material for bulk-heterojunction organic solar cells (BJH-OSCs). The photophysical properties, optoelectrical characterization and microscopic images were thoroughly studied. H3T-ID exhibited good absorption behavior with maximum absorbance at ~495 nm and displayed the optical band gap of ~1.98 eV. The existence of π-spacer and hexyl side chain in H3T-ID significantly improved the thin film morphology, molecular packing and enhanced the charge transport. H3T-ID organic molecule acquired well-matched HOMO and bountifully higher LUMO energy levels w.r.t. PC61BM acceptor. The photovoltaic characteristics of the fabricated BHJ-OSC using H3T-ID as donor and PC61BM as acceptor displayed maximum PCE = ~4.05%, good JSC = ~10.43 mAcm?2, VOC = ~0.77 V and FF = 0.51. The stability test revealed that the fabricated BHJ-OSCs showed good reproducibility and stability by retaining over ~80% of its initial PCE for 15 days without encapsulation.
关键词： Stability,Indanedione,Planar,Heterojunction,Organic solar cell
更新于2025-09-23 15:19:57
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On the use of multiple stacked active layers in organic photovoltaic cells
摘要： In the field of organic photovoltaic cells (OPVs), ternary planar heterojunction allows widening absorption range. Optimization of the energy levels at the organic interfaces is the first task to achieve in order to obtain OPVs with high efficiency. In ternary OPVs, carrier mobility, charge transfer and presence of energy transfer are determinant. Here, we compare the performances of different, binary (electron donor/fullerene) and ternary (electron donor/ambipolar material/fullerene) combinations of small organic molecules in planar heterojunction (PHJ) cells. We chose the different ED molecules in order to investigate the different possible band scheme alignments. The study shows that if the open circuit voltage (Voc) is limited by the energy levels of the outer layers, i.e. the difference between the lowest unoccupied molecular orbital (LUMO) of the electron acceptor and the highest occupied molecular orbital (HOMO) of the outer electron donor layer, the energy loss can be smaller than 0.2 eV. If efficient ternary OPVs need global energy offset higher than the exciton energy to separate the charges of the exciton, the distribution of this offset between DLUMO and DHOMO is not critical. The mobility value of the carriers in the intercalated layer is determinant in obtaining performance of OPVs. Overlap between the photoluminescence of ED and the optical absorption of EDA is primordial for good energy transfer. The highest OPV efficiency improvement is obtained with organic materials such as ED and EDA that have the same HOMO and similar hole mobility which give homogeneous thin layers.
关键词： organic photovoltaic cells,energy levels,energy transfer,carrier mobility,charge transfer,ternary planar heterojunction
更新于2025-09-23 15:19:57
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Novel antisolvent-washing strategy for highly efficient carbon-based planar CsPbBr3 perovskite solar cells
摘要： All-inorganic CsPbBr3 is attracting tremendous attentions in photovoltaic field due to its superior stability. However, CsPbBr3 perovskite always suffers from a poor crystallinity and film morphology. Many efforts have been paid on the CsBr deposition process to improve the film quality, while few attentions are paid on the crystallization kinetics of the PbBr2 framework film. Here, we demonstrate a novel antisolvent-washing strategy for the PbBr2 film for the first time to fabricate high-quality CsPbBr3 film. This technique has a significant impact on the nucleation and growth of PbBr2 crystals. As-prepared CsPbBr3 films exhibit more homogeneous with higher crystallinity and coverage as well as larger grain sizes compared to those untreated ones. The best-performing antisolvent-treated perovskite solar cell achieves a scanned power conversion efficiency of 8.55%, which is an excellent efficiency for planar CsPbBr3 cells reported yet. This enhancement can be mainly attributed to the more effective charge transport and suppressed non-radiative recombination caused by the reduced defect densities. Moreover, our devices show superb stability when stored in air for 1000 h and upon persistent thermal attack at 80°C. Our work provides a new train of thought for controlling the growth dynamics and film morphology of CsPbBr3 films.
关键词： Antisolvent-washing,CsPbBr3,Planar heterojunction,High efficiency and stability,Carbon-based,Low costs
更新于2025-09-19 17:13:59
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On the contribution of fullerene to the current of planar heterojunction organic solar cells.
摘要： Recently, significant progress in the field of organic photovoltaic cells was obtained by substituting new electron acceptor molecules to the fullerene, which was attributed to the fact that the fullerene absorption is quite small. Nevertheless, we demonstrate in the present work that, in the case of inverted cells, i.e. when the transparent bottom electrode is used as cathode, the contribution of fullerene to the Jsc short-circuit current of the cells, if not dominant, is not negligible; and that mainly in the short wavelength spectral range. The experimental results are confirmed by an optical simulation. Due to this significant contribution to Jsc, the light transmission of the transparent electrode towards the UV-part of the spectrum is crucial for inverse cell performances. When a transparent conductive electrode based on an alternative dielectric/metal/dielectric structure is substituted to ITO, such as ZnS/Ag/TiO2, the study allows to obtain promising results, although there is a loss of performance due to the decrease of transmission of TiO2 below 400 nm in wavelength.
关键词： Absorption,Optical Modeling,External Quantum Efficiency,Organic solar cells,Planar heterojunction
更新于2025-09-19 17:13:59
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Highly efficient planar heterojunction perovskite solar cells with sequentially dip-coated deposited perovskite layers from a non-halide aqueous lead precursor
摘要： High-performance planar heterojunction (PHJ) perovskite solar cells (PrSCs) with MAPbI3 perovskite films were fabricated using a facile, environmentally benign, efficient and low-cost dip-coating deposition approach on a bilayered ZnO/TiO2 electron transport system from aqueous non-halide Pb(NO3)2. Outstanding performance of PrSCs was achieved due to the PHJ configuration of FTO/TiO2/ZnO/MAPbI3/spiro-OMeTAD/MoO3/Ag. These PHJ PrSCs exhibited better performance and stability with thinner ZnO layers in contrast to those with mesoporous TiO2 scaffolds, indicating that the thickness of the ZnO layer in the PHJ architecture significantly affected the surface coverage, morphology, crystallinity, and stability of the MAPbI3 perovskite films processed by dip-coating deposition.
关键词： ZnO/TiO2 electron transport system,perovskite solar cells,planar heterojunction,dip-coating deposition,aqueous non-halide Pb(NO3)2
更新于2025-09-19 17:13:59
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Reducing Photovoltage Loss in Inverted Perovskite Solar Cells by Quantum Dots Alloying Modification at Cathode Contact
摘要： The tremendous passion for inverted planar heterojunction perovskite solar cells (PSCs) is originated from their great tendency in the Roll-to-Roll process compatible fabrication and huge potential for integration into tandem solar cells. But the device efficiency is still lower than regular structured PSCs. Engineering of the cathode interface to efficiently control and reduce VOC loss light a lamp for increasing electrochemical properties and boosting overall performance. In this work, a simple interfacial modification strategy was developed by introducing a hybrid ligands interfacial layer to reduce VOC loss in PSCs with inverted planar structure. Heavily washed QDs was used as a neutral charged intermedia to enable alloying reaction to transfer ligands without damage perovskite. A band bending immediately generated on top surface of perovskite film after QDs modification, which was directly convinced by UPS and KPFM. This contributed to ~50 mV reduced VOC loss, leading to a VOC of 1.15 V and a PCE of 20.6% in inverted PSCs. Meanwhile, enhanced stability achieved for these devices after QDs modification, in which PCE keeping > 90% of initial value after 1000 hours' storage.
关键词： inverted planar heterojunction perovskite solar cells,perovskite quantum dots,photovoltage,electron transport layer,passivation
更新于2025-09-12 10:27:22
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Enhanced photovoltaic performance and stability of planar perovskite solar cells by introducing dithizone
摘要： In the two-step spin-coating method, the crystallization and morphology of PbI2 film are essential for producing highly efficient and stable planar heterojunction (PHJ) perovskite solar cells. In this work, the dithizone (DTZ) molecules were introduced into PbI2 precursor to improve the performance of perovskite films. We found that adding DTZ was an effective method to retard the crystallization of PbI2 film and consequently, produced a high-quality perovskite film with pinhole-free, smoother, and fewer defects surface. Most importantly, the presence of residual DTZ in wet PbI2 film also assisted DMSO to slow down the growth of perovskite grains. By tuning the concentration of DTZ, the power conversion efficiency of the best performed cell has increased to 20.66% with negligible photocurrent hysteresis. Meanwhile, the best DTZ device offer an excellent stability, which retained 97% of the initial PCE after storage in the dark for approximately 24 days. We expect this controlled crystallization method could be further explored and provides a useful strategy to improve the performance of perovskite solar cells.
关键词： Planar heterojunction,Dithizone,Perovskite solar cells,Two-step spin-coating method,Chelating agents
更新于2025-09-12 10:27:22