Photon Acceleration Using a Time-Varying Epsilon-near-Zero Metasurface

Liu, Cong; Alam, M. Zahirul; Pang, Kai; Manukyan, Karapet; Reshef, Orad; Zhou, Yiyu; Choudhary, Saumya; Patrow, Joel G.; Pennathurs, Anuj; Song, Hao; Zhao, Zhe; Zhang, Runzhou; Alishahi, Fatemeh; Fallahpour, Ahmad; Cao, Yinwen; Almaiman, Ahmed; Dawlaty, Jahan M.; Tur, Moshe; Boyd, Robert W.

doi:10.1021/acsphotonics.0c01929

Cited by 39 publications

(34 citation statements)

References 27 publications

(46 reference statements)

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“…This absence of charge transfer state is commonly in high performance BHJ OSC systems, and is beneficial for reducing energy loss of OSC devices. [ 54–57 ]…”

Section: Resultsmentioning

confidence: 99%

An Electron Acceptor Analogue for Lowering Trap Density in Organic Solar Cells

et al. 2021

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Typical organic semiconductor materials exhibit a high trap density of states, ranging from 1016 to 1018 cm−3, which is one of the important factors in limiting the improvement of power conversion efficiencies (PCEs) of organic solar cells (OSCs). In order to reduce the trap density within OSCs, a new strategy to design and synthesize an electron acceptor analogue, BTPR, is developed, which is introduced into OSCs as a third component to enhance the molecular packing order of electron acceptor with and without blending a polymer donor. Finally, the as‐cast ternary OSC devices employing BTPR show a notable PCE of 17.8%, with a low trap density (1015 cm−3) and a low energy loss (0.217 eV) caused by non‐radiative recombination. This PCE is among the highest values for single‐junction OSCs. The trap density of OSCs with the BTPR additives, as low as 1015 cm−3, is comparable to and even lower than those of several typical high‐performance inorganic/hybrid counterparts, like 1016 cm−3 for amorphous silicon, 1016 cm−3 for metal oxides, and 1014 to 1015 cm−3 for halide perovskite thin film, and makes it promising for OSCs to obtain a PCE of up to 20%.

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“…This absence of charge transfer state is commonly in high performance BHJ OSC systems, and is beneficial for reducing energy loss of OSC devices. [ 54–57 ]…”

Section: Resultsmentioning

confidence: 99%

An Electron Acceptor Analogue for Lowering Trap Density in Organic Solar Cells

et al. 2021

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“…To further understand the effect of the extended π‐conjugation TVT on exciton dissociation and carrier generation, the dependence of photogenerated current density ( J ph ) versus effective voltage ( V eff ) was measured, and the results are depicted in Figure 5E. [ 43 ] The variable J ph can be defined as J ph = J L − J D ( J L and J D are respectively the light and dark current densities), while the dependent variable V eff is defined as V eff = V 0 − V a ( V a is the applied bias voltage and V 0 is the voltage at which J ph is zero). The charge separation efficiency P(E,T) can be assessed from the value of J ph /J sat under the short‐circuit condition, where J sat is current densities at saturation condition.…”

Section: Resultsmentioning

confidence: 99%

π‐Extended Conjugated Polymer Acceptor Containing Thienylene–Vinylene–Thienylene Unit for High‐Performance Thick‐Film All‐Polymer Solar Cells with Superior Long‐Term Stability

Zhang

Tan

Zhang

et al. 2021

Advanced Energy Materials

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Despite the rapid developments in all‐polymer solar cells (all‐PSCs) due to the progress of polymerized small molecular acceptors (PSMA), the effect of linkage unit conjugation on the polymer acceptor (PA) is not well understood and PAs with high efficiency, good stability, and thickness‐insensitivity are rarely seen. Herein, two novel PSMAs, named PJTVT and PJTET are designed, by incorporating conjugated thienylene‐vinylene‐thienylene (TVT) and unconjugated thienylene–ethyl–thienylene (TET) units, respectively. Results show that the energy levels, energy losses, and energy offset of the two PSMAs have little difference (<≈0.03 eV). However, due to the π‐extended coplanar backbone of PJTVT, when blended with polymer donor JD40, a more ordered π–π stacking and enhanced face‐on orientation morphology is observed, which contributes to enhanced exciton dissociation, superior charge transport, and faster charge extraction, leading to a record power conversion efficiency of 16.13% (10.93% for JD40:PJTET). Impressively, the JD40:PJTVT device shows superior thickness‐insensitivity and long‐term stability, both of which make it an ideal choice for industrialization. These results demonstrate that molecular modulation in the linking unit is a promising strategy to construct PSMAs for high‐performance thick‐film all‐PSCs with superior long‐term stability, and shows the superiority of conjugated backbones for PSMAs.

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“…[ 5,6 ] There has been much exploration of the state‐of‐art photovoltaic performance, with methods that mainly concentrate on the molecular design, structure modification of devices, and the construction of active layers. [ 7–9 ] Through innovative molecular design and matching with suitable donors, the Y6 system has opened a new vista in which the efficiency of non‐fullerene solar cells (NFSC) approached 16%. [ 10 ] To date, subsequent optimizations have brought a brighter future with the PCE in single‐junction devices exceeding 18%.…”

Section: Introductionmentioning

confidence: 99%

Nanographene–Osmapentalyne Complexes as a Cathode Interlayer in Organic Solar Cells Enhance Efficiency over 18%

et al. 2021

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Development of power conversion efficiency (PCE) and short-term stability are still huge challenges that restrict the actual industrialization of OSCs. [5,6] There has been much exploration of the state-of-art photovoltaic performance, with methods that mainly concentrate on the molecular design, structure modification of devices, and the construction of active layers. [7][8][9] Through innovative molecular design and matching with suitable donors, the Y6 system has opened a new vista in which the efficiency of nonfullerene solar cells (NFSC) approached 16%. [10] To date, subsequent optimizations have brought a brighter future with the PCE in single-junction devices exceeding 18%. [11][12][13][14] Together with molecular innovation, interface engineering also improves the device performances continually. Gene rally, interface engineering implies that through insertion of a single or double interlayer between an active layer and a cathode or anode to improve the indirect contact between them, and further regulation of the morphology or work function of electrodes, the devices can be improved. Included amongst the most popular interfacial materials, there are several main types: [15] metal oxides (MO), including the commonly used ZnO [16] and MoOx, alcohol-soluble polymers and small molecules such as amino PDINO [17] and PFN-Br, [18] Interface engineering is a critical method by which to efficiently enhance the photovoltaic performance of nonfullerene solar cells (NFSC). Herein, a series of metal-nanographene-containing large transition metal involving d π -p π conjugated systems by way of the addition reactions of osmapentalynes and p-diethynyl-hexabenzocoronenes is reported. Conjugated extensions are engineered to optimize the π-conjugation of these metal-nanographene molecules, which serve as alcohol-soluble cathode interlayer (CIL) materials. Upon extension of the π-conjugation, the power conversion efficiency (PCE) of PM6:BTP-eC9-based NFSCs increases from 16% to over 18%, giving the highest recorded PCE. It is deduced by X-ray crystallographic analysis, interfacial contact methods, morphology characterization, and carrier dynamics that modification of hexabenzocoronenes-styryl can effectively improve the short-circuit current density (J sc ) and fill factor of organic solar cells (OSCs), mainly due to the strong and ordered charge transfer, more matching energy level alignments, better interfacial contacts between the active layer and the electrodes, and regulated morphology. Consequently, the carrier transport is largely facilitated, and the carrier recombination is simultaneously impeded. These new CIL materials are broadly able to enhance the photovoltaic properties of OSCs in other systems, which provides a promising potential to serve as CILs for higher-quality OSCs.

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Photon Acceleration Using a Time-Varying Epsilon-near-Zero Metasurface

Cited by 39 publications

References 27 publications

An Electron Acceptor Analogue for Lowering Trap Density in Organic Solar Cells

An Electron Acceptor Analogue for Lowering Trap Density in Organic Solar Cells

π‐Extended Conjugated Polymer Acceptor Containing Thienylene–Vinylene–Thienylene Unit for High‐Performance Thick‐Film All‐Polymer Solar Cells with Superior Long‐Term Stability

Nanographene–Osmapentalyne Complexes as a Cathode Interlayer in Organic Solar Cells Enhance Efficiency over 18%

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