The diverse molecular stacking tuned by peripheral halogens in non-fullerene acceptors (NFAs) significantly affects the molecular physicochemical properties, the film morphologies and thus the power ...conversion efficiencies (PCEs) of organic solar cells (OSCs). Despite the crucial role of peripheral halogens, few explorations have been performed to bridge peripheral halogenation with molecular stackings and device performances, especially for the state-of-the-art
Y
-series. Herein, a series of high-efficient NFAs,
CH-6F
,
CH-4Cl
and
CH-6Cl
, are constructed with the same backbone but different peripheral halogenations in both conjugate extended central units and end groups. Single-crystal analysis indicates that
CH-6F
possesses similar molecular packings to
Y6;
however,
CH-4Cl
and
CH-6Cl
with chloro-substitutions demonstrate several quite unique packing modes of end unit to central unit,
etc.
Compared with
CH-6F
and
Y6
,
CH-4Cl
and
CH-6Cl
possess greatly reduced electron reorganization energies and shorter intermolecular packing distances, and exhibit more balanced charge mobilities, better phase separation, and lower energy disorders when blended with the
PM6
donor. Furthermore, the reduced energy offsets between charge transfer and local exciton states for
CH-4Cl
and
CH-6Cl
result in an enhanced hybridization of these two states and thus suppress the non-radiative recombination losses in OSCs. Consequently, high-efficient OSCs are afforded by utilizing
CH
-series NFAs with a champion PCE of 18.22% and a markedly reduced Δ
V
nr
of 0.203 V in
CH-4Cl
-based ternary devices. Our study reveals that such a slight modification of peripheral halogens could cause quite different but superior intermolecular packings, rendering peripheral halogenation engineering as an effective strategy to further boost PCEs of high-performance OSCs through delicate molecular stacking control.
The diverse molecular stacking tuned by peripheral halogens in non-fullerene acceptors (NFAs) significantly affects the molecular physicochemical properties, the film morphologies and thus the power conversion efficiencies (PCEs) of organic solar cells (OSCs).
Reported are two highly efficient metal‐free perylene dyes featuring N‐annulated thienobenzoperylene (NTBP) and N‐annulated thienocyclopentaperylene (NTCP), which are coplanar polycyclic aromatic ...hydrocarbons. Without the use of any coadsorbate, the metal‐free organic dye derived from the NTCP segment was used for a dye‐sensitized solar cell which attained a power conversion efficiency of 12 % under an irradiance of 100 mW cm−2, simulated air mass global (AM1.5G) sunlight.
Power trip: A perylene dye derived from N‐annulated thienocyclopentaperylene, which is characterized by a low‐energy gap and a high electron injection yield, was synthesized for dye‐sensitized solar cells. A high power conversion efficiency of 12 %, at an irradiance of the AM1.5G sunlight, was achieved. This efficiency is the highest achieved thus far by using just a metal‐free organic dye.
An electron-donor with a polycyclic aromatic hydrocarbon dithieno2',3':2,3; 3'',2'':10,11piceno1,14,13,12-bcdefghcarb azole (DTPC) as the primary skeleton and also decorated with multiple ...solubilizing groups is coupled to 4-(benzoc1,2,5thiadiazol-4-ylethynyl)benzoic acid, for a metal-free organic dye (C281). The near-infrared photosensitizing dye exhibits over 80% external quantum efficiency in a broad spectral range from 480 nm to 735 nm, and a high power conversion efficiency of 13.0% under irradiance of simulated AM 1.5G sunlight (100 mW cm super(-2)).
Perovskite solar cells (PSCs) has skyrocketed in the past decade to an unprecedented level due to their outstanding photoelectric properties and facile processability. However, the utilization of ...expensive hole transport materials (HTMs) and the inevitable instability instigated by the deliquescent dopants represent major concerns hindering further commercialization. Here, a series of low-cost, conjugated polymers are designed and applied as dopant-free HTMs in PSCs, featuring tuned energy levels, good temperature and humidity resistivity, and excellent photoelectric properties. Further studies highlight the critical and multifaceted roles of the polymers with respect to facilitating charge separation, passivating the surface trap sites of perovskite materials, and guaranteeing long-term stability of the devices. A stabilized power conversion efficiency (PCE) of 20.3% and remarkably enhanced device longevity are achieved using the dopant-free polymer P3 with a low concentration of 5 mg/mL, qualifying the device as one of the best PSC systems constructed on the basis of dopant-free HTMs so far. In addition, the flexible PSCs based on P3 also exhibit a PCE of 16.2%. This work demonstrates a promising route toward commercially viable, stable, and efficient PSCs.
Given that bromine possesses similar properties but extra merits of easily synthesizing and polarizing comparing to homomorphic fluorine and chlorine, it is quite surprising very rare ...high-performance brominated small molecule acceptors have been reported. This may be caused by undesirable film morphologies stemming from relatively larger steric hindrance and excessive crystallinity of bromides. To maximize the advantages of bromides while circumventing weaknesses, three acceptors (CH20, CH21 and CH22) are constructed with stepwise brominating on central units rather than conventional end groups, thus enhancing intermolecular packing, crystallinity and dielectric constant of them without damaging the favorable intermolecular packing through end groups. Consequently, PM6:CH22-based binary organic solar cells render the highest efficiency of 19.06% for brominated acceptors, more excitingly, a record-breaking efficiency of 15.70% when further thickening active layers to ~500 nm. By exhibiting such a rare high-performance brominated acceptor, our work highlights the great potential for achieving record-breaking organic solar cells through delicately brominating.
Correction for 'Peripheral halogenation engineering controls molecular stacking to enable highly efficient organic solar cells' by Yalu Zou
et al.
,
Energy Environ. Sci.
, 2022,
...https://doi.org/10.1039/d2ee01340a
.
In this work, by conjugating 2-cyanoacrylic acid (CA), 4-(benzoc1,2,5thiadiazol-7-yl)benzoic acid (BTBA), 4-(7-ethynylbenzoc1,2,5thiadiazol-4-yl)benzoic acid (EBTBA), and ...4-((7-ethynylbenzoc1,2,5thiadiazol-4-yl)ethynyl)benzoic acid (EBTEBA) to a binary electron-donor diphenylamine-phenanthrocarbazole (DPA-PC), we systematically investigate the impacts of electron-acceptors upon energy level, energy gap, light-harvesting ability, photovoltaic parameter, and cell stability of donor–acceptor dyes in photoelectrochemical cells. In conjunction with an ionic liquid composite electrolyte, the DPA-PC dye with EBTEBA as electron-acceptor yields a high power conversion efficiency of 8% and an outstanding stability after a 1000 h aging test under the soaking of full sunlight at 60 °C in a dye-sensitized solar cell. Femtosecond fluorescence up-conversion measurements have suggested that energy relaxation and electron injection both occur to dye molecules in the nonequilibrium excited states. Moreover, the time constants of injecting electrons from dye molecules in the excited states to titania are very dispersive for over 1 order of magnitude, mainly owing to the broad energy distribution of excited states.
A novel two-dimensional A-D-A acceptor named as
CH8
with four electron-withdrawing end units has been successfully designed and synthesized. The enlarged conjugation in two directions renders
CH8
...exhibit an extremely low electron reorganization energy of 98 meV, which makes
CH8
a potential candidate for outstanding organic semiconductor material. When blended with
PM6
, a considerate power conversion efficiency of 9.37% along with a high open-circuit voltage (
V
oc
) 0.889 V and low energy loss (
E
loss
) below 0.6 eV is achieved. These results indicate that the two-dimensional A-D-A molecule with four electron-withdrawing end units is an effective molecular design strategy to achieve lower voltage loss and also possible high performance for organic photovoltaics if ideal morphology could be achieved.
The growth of artificial intelligence leads to a computational burden in solving non-deterministic polynomial-time (NP)-hard problems. The Ising computer, which aims to solve NP-hard problems faces ...challenges such as high power consumption and limited scalability. Here, we experimentally present an Ising annealing computer based on 80 superparamagnetic tunnel junctions (SMTJs) with all-to-all connections, which solves a 70-city traveling salesman problem (TSP, 4761-node Ising problem). By taking advantage of the intrinsic randomness of SMTJs, implementing global annealing scheme, and using efficient algorithm, our SMTJ-based Ising annealer outperforms other Ising schemes in terms of power consumption and energy efficiency. Additionally, our approach provides a promising way to solve complex problems with limited hardware resources. Moreover, we propose a cross-bar array architecture for scalable integration using conventional magnetic random-access memories. Our results demonstrate that the SMTJ-based Ising computer with high energy efficiency, speed, and scalability is a strong candidate for future unconventional computing schemes.
In this article, we report two metal-free perylene dyes (C269 and C270) featuring the electron acceptors benzothiadiazole–benzoic acid and ethynylbenzothiadiazole–benzoic acid, respectively, in ...combination with a bis(4-(hexyl)phenyl)amino-capped N-annulated perylene (NP) electron donor. Density functional theory (DFT) and time-dependent DFT (TDDFT) calculations revealed that the use of ethynylbenzothiadiazole–benzoic acid can lower the level of the lowest unoccupied molecular orbital (LUMO), reduce the energy gap, and attenuate the Stokes shift of an NP dye. These effects are in good accord with electrochemical and photophysical measurements. When used in sensitized titania solar cells, C270 dye exhibits a reasonably good power conversion efficiency close to 9% at an irradiance of 100 mW cm–2 simulated AM1.5 sunlight. It was also found that, with respect to C269, C270 dye forms a thinner and looser self-assembled dye layer on the surface of titania, accounting for the shorter electron lifetime and lower open-circuit photovoltage for cells made with C270. Our femtosecond transient absorption (fs-TA) measurements confirmed a positive relationship between the driving energy and electron-injection rate despite the close-to-unity electron-injection yields for both dyes. In addition, the target analysis of fs-TA data indicated that, with respect to C269, more electrons are injected from the relaxed excited states for C270 dye with a lower LUMO level.
