We demonstrate that a poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate)/diindenoperylene (PEDOT:PSS/DIP) interfacial bilayer could serve as a structural template to enable the morphological control of bulk heterojunctions (BHJs) by co-evaporation of tetraphenyldibenzoperiflanthene:fullerene (DBP:C), which greatly improves the device performances. Especially, we show that isolated crystalline domains of C can be well-controlled at the nanoscale during the co-evaporation. Photoluminescence spectra indicate the realization of DIP/DBP cascade energy architecture, which significantly facilitates both the energy transfer and photocurrent generation. In addition, with bias-dependent external quantum efficiency analysis, we reveal that such a cascade energy device architecture greatly suppresses the energy recombination in both carrier and exciton transfer, resulting in a high open-circuit voltage and a high fill factor. By carefully optimizing the interfacial and BHJ layers, we achieved a high-performance organic photovoltaic cell with a power conversion efficiency of 5.0 ± 0.3%.
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http://dx.doi.org/10.1021/acsami.7b13989 | DOI Listing |
Adv Sci (Weinh)
December 2024
Center on Nanoenergy Research, Carbon Peak and Neutrality Science and Technology Development Institute, School of Physical Science & Technology, Guangxi University, Nanning, 530004, China.
Nonfullerene acceptors are critical in advancing the performance of organic solar cells. However, unfavorable morphology and low photon-to-electron conversion in the acceptor range continue to limit the photocurrent generation and overall device performance. Herein, benzoic anhydride, a low-cost polar molecule with excellent synergistic properties, is introduced in combination with the traditional additive 1-chloronaphthalene to optimize the aggregation of nonfullerene acceptors.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
December 2024
Sun Yat-sen University - Shenzhen Campus, Schoolof Materials, Shenzhen, Guangdong 518107, P. R. China, 518000, Shenzhen, CHINA.
Morphology control of the photoactive layer is crucial for achieving high-performance organic solar cells (OSCs), yet it remains a significant challenge in this field. One effective approach is the additive strategy, which fine-tunes the morphology of the photoactive layer. However, the underlying mechanisms governing the impact of different types of additives from liquid, solid, to volatile solid, on the bulk heterojunction morphology and device performance are not fully understood.
View Article and Find Full Text PDFJ Chem Phys
December 2024
Graduate School of Science and Technology, Niigata University, 2-8050 Ikarashi, Nishi-ku, Niigata 950-2181, Japan.
For the clarification of dynamics of photogenerated carriers in practical organic solar cell devices, we have developed a methodology to simultaneously acquire reflection-mode transient optical absorption (ΔA) and transient electric current (Δi) signals. For a typical polythiophene:fullerene bulk heterojunction solar cell device, both the ΔA and Δi signals due to the photogenerated carriers are characterized by the power-law decays of ∝t-α, which are interpreted by detrapping-limited recombination at earlier times than ∼1 μs and trap-free diffusion/drift at later times. Furthermore, we have succeeded in observing switching of the power index α for ΔA signals as well as for Δi signals; the time at which switching occurs indicates the extraction of carriers by electrodes (transit times).
View Article and Find Full Text PDFJ Am Chem Soc
December 2024
Department of Chemical Engineering, National Tsing Hua University, Hsinchu 300044, Taiwan.
Mini-emulsion and nanoprecipitation techniques relied on large amounts of surfactants, and unresolved miscibility issues of heterojunction materials limited their efficiency and applicability in the past. Through our molecular design and developed surfactant-free precipitation method, we successfully fabricated the best miscible bulk-heterojunction-particles (BHJP) ever achieved, using donor () and acceptor () polymers. The structural similarity ensures optimal miscibility, as supported by the interaction parameter of the / blend is positioned very close to the binodal curve.
View Article and Find Full Text PDFMacromol Rapid Commun
December 2024
Key Laboratory of Photoelectric Conversion and Utilization of Solar Energy, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, 266101, China.
In order to realize high-performance bulk-heterojunction (BHJ) all-polymer solar cells, achieving appropriate aggregation and moderate miscibility of the polymer blends is one critical factor. Herein, this study designs and synthesizes two new polymer acceptors (Ps), namely PYF and PYF-Cl, containing benzo[1,2-b:4,5-b'] difuran (BDF) moiety with/without chlorine atoms on the thiophene side groups. Thanks to the preferred planar structure and high electronegativity of the BDF units, the resultant Ps generate strong intermolecular interactions and π-π stacking in both the neat and blend films.
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