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Non-fullerene small molecule acceptors with three-dimensional thiophene/selenophene-annulated perylene diimides for efficient organic solar cells
摘要： Three-dimensional non-fullerene acceptors with a spiro core linked with S/Se fused perylene diimides possess appropriate energy levels, twisted molecular configuration and high carrier mobility, leading to a power conversion efficiency of 6.95% for the organic solar cells.
关键词： perylene diimides,organic solar cells,carrier mobility,non-fullerene acceptors,spiro core
更新于2025-09-23 15:21:01
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Naphthalene and perylene diimides – better alternatives to fullerenes for organic electronics?
摘要： The LUMO levels of rylene diimides are highly comparable to those of fullerenes but this class of molecules offers tunability of both HOMO and LUMO levels and the related band gap by either simple substitution at the aromatic core or annulation to give expanded p-scaffolds. In this article we highlight the most outstanding achievements during the last decade in terms of charge carrier mobility for organic thin-film and single crystal field-effect transistors as well as photovoltaic performance for both small molecule and polymeric compounds.
关键词： fullerenes,perylene diimides,organic electronics,photovoltaic performance,naphthalene diimides,charge carrier mobility
更新于2025-09-19 17:15:36
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Afterglow Effects as a Tool to Screen Emissive Non-Geminate Charge Recombination Processes in Organic Photovoltaic Composites
摘要： Disentangling temporally-overlapping charge carrier recombination events in organic bulk heterojunctions by optical spectroscopy is challenging. Here, a new methodology for employing delayed luminescence spectroscopy is presented. The proposed method is capable of distinguishing between recombination of spatially-separated charge carriers and trap-assisted charge recombination simply by monitoring the delayed luminescence (afterglow) of bulk heterojunctions with a quasi time-integrated detection scheme. Applied on the model composite of the donor poly(6,12-dihydro-6,6,12,12-tetraoctyl-indeno[1,2-b]fluorene-alt-benzothiadiazole) (PIF8BT) polymer and the acceptor ethyl-propyl perylene diimide (PDI) derivative, i.e. PIF8BT:PDI, the luminescence of charge-transfer (CT) states created by non-geminate charge recombination on the ns – μs time scale is observed. Fluence-dependent, quasi time-integrated detection of the CT luminescence monitors exclusively emissive charge recombination events, while rejecting the contribution of other early-time emissive processes. Trap-assisted and bimolecular charge recombination channels are identified based on their distinct dependence on fluence. The importance of the two recombination channels is correlated with the layer’s order and electrical properties of the corresponding devices. Four different microstructures of the PIF8BT:PDI composite obtained by thermal annealing are investigated. Thermal annealing of PIF8BT:PDI shrinks the PDI domains in parallel with the growth of the PIF8BT domains in the blend. Common to all states studied, the delayed CT luminescence signal is dominated by trap-assisted recombination. Yet, the minor fraction of fully-separated charge recombination in the overall CT emission increases as the difference in the size of the donor and acceptor domains in the PIF8BT:PDI blend becomes larger. Electric field-induced quenching measurements on complete PIF8BT:PDI devices confirm quantitatively the dominance of emissive trap-limited charge recombination and demonstrate that only 40% of the PIF8BT/PDI CT luminescence comes from the recombination of fully-separated charges, taking place within 200 ns after photoexcitation. The method is applicable to other non-fullerene acceptor blends beyond the system discussed here, if their CT state luminescence can be monitored.
关键词： multiple-diode equivalent circuit,fill factor,solar cell,charge trapping,perylene diimides,non-fullerene acceptors,delayed luminescence,photodetector
更新于2025-09-12 10:27:22
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Chalcogen‐Fused Perylene Diimides‐Based Non‐Fullerene Acceptors for High Performance Organic Solar Cells: Insight into the Effect of O, S and Se
摘要： Three perylene diimide tetramers annulated by oxygen (O), sulfur (S) and selenium (Se), named as SF-4PDI-O, SF-4PDI-S and SF-4PDI-Se, are designed, synthesized and paired with polymeric donor PDBT-T1 to construct OSCs. The heteroatoms’ effect on photoelectric properties, chemical geometry, charge transport, active-layer morphology, and photovoltaic performance are investigated in detail. These PDI acceptors exhibit similar absorption profile; while HOMOs and LUMOs are simultaneously upshifted when heteroatoms are altered from O, S to Se due to the gradually weakening electronegativity. Alongside PDBT-T1, SF-4PDI-O achieved the outstanding PCE of 8.904% with a high FF of 0.706, outcompeting its S-annulated and Se-annulated counterparts. The superiority of PDBT-T1: SF-4PDI-O system lies in stronger crystallinity, more balanced hole and electron mobilities, weaker bimolecular recombination, coupled with more efficient charge transfer and collection. These results shed light on the invention of high-performance PDI acceptors by oxygen-decorated methodology.
关键词： chalcogen,nonfullerene,organic solar cells,perylene diimides,small molecule acceptors
更新于2025-09-11 14:15:04