Novel donor-acceptor-donor structured small molecular hole transporting materials for planar perovskite solar cells

Novel donor-acceptor-donor structured small molecular hole transporting materials are developed through a facile route by crosslinking dithienopyrrolobenzothiadiazole and phenothiazine or triarylamine-based donor units. The strong push/pull electron capability of dithienopyrrolobenzothiadiazole/ phenothiazine and large π-conjugated dithienopyrrolobenzothiadiazole facilitate hole mobility and high conductivity. The devices using the dithienopyrrolobenzothiadiazole/phenothiazine-based hole trans-porting material achieved a power conversion efficiency of 14.2% under 1 sun illumination and improved stability under 20% relative humidity at room temperature without encapsulation. The present finding highlights the potential of dithienopyrrolobenzothiadiazole-based donor-acceptor-donor small molecular hole transporting materials for perovskite solar cells.

Crystal Structure and Spectroscopic Properties of the Donor-acceptor Complex of 2-Amino-1,3-benzo- thiazole with Ethyl-5,6-benzocoumarin-3-carboxylate

The donor-acceptor complex derived from 2-amino-1,3-benzothiazole （ABT） and ethyl 5,6-benzocoumarin-3-carboxylate （EBCC） has been synthesized and its crystal structure was determined by single-crystal X-ray diffraction. The crystal belongs to the monoclinic system, space group P21/c, with a = 8.6485（3）, b = 7.7743（3）, c = 29.1963（10） A, β = 92.0460（10）°, Z = 4, Mr = 418.45, V= 1961.79（12） A^3, Dc = 1.417 g/cm^3,μ = 0.199 mm^-1, F（000） = 872, the final R = 0.0350 and wR = 0.1226. The complex is an A…D…D＇…A＇ H-bonded tetramer. The intermolecular N-H…O and N-H…N hydrogen bonds, together with π-π stacking interactions, stabilize the crystal structure by forming a supramolecular architecture. It is found that, in solid state, the fluorescence emission of the complex is quenched significantly while the UV-vis spectrum exhibits a broad band at 346 nm with shoulder, which can be attributed to the donor-acceptor complex formed.

The prediction of donor number and acceptor number of electrolyte solvent molecules based on machine learning

Electrolyte solvents have a critical impact on the design of high performance and safe batteries.Gutmann's donor number(DN) and acceptor number(AN) values are two important parameters to screen and design superior electrolyte solvents. However, it is more time-consuming and expensive to obtain DN and AN values through experimental measurements. Therefore, it is essential to develop a method to predict DN and AN values. This paper presented the prediction models for DN and AN based on molecular structure descriptors of solvents, using four machine learning algorithms such as Cat Boost(Categorical Boosting), GBRT(Gradient Boosting Regression Tree), RF(Random Forest) and RR(Ridge Regression).The results showed that the DN and AN prediction models based on Cat Boost algorithm possesses satisfactory prediction ability, with R^(2) values of the testing set are 0.860 and 0.96. Moreover, the study analyzed the molecular structure parameters that impact DN and AN. The results indicated that TDB02m(3D Topological distance based descriptors-lag 2 weighted by mass) had a significant effect on DN, while HATS1s(leverage-weighted autocorrelation of lag 1/weighted by I-state) plays an important role in AN. The work provided an efficient approach for accurately predicting DN and AN values, which is useful for screening and designing electrolyte solvents.

The origin and evolution of Y6 structure

During last several years,electron acceptors for organic sol-ar cells(OSCs)have experienced three major innovations.The first invention was a fused-ring electron acceptor(FREA),ITIC,reported by Zhan et al.in 2015,which consists of an in-dacenodithienothiophene(IDTT)donor core and two 3-dicy-anomethylene-1-indanone(IC)as the end-groups[1].ITIC cells exhibited comparable performance to PC61BM cells,and in-spired the development of hundreds nonfullerene acceptors(NFAs).The second breakthrough is the 14.08%power con-version efficiency(PCE)delivered by a low-bandgap non-fullerene acceptor COi 8DFIC with strong NIR absorption,invented by Ding et al.[2,3].The third star acceptor is Y6,developed by Zou et al.in 2019[4].Y6 and its derivatives(Y-series NFAs)are very promising[5,6].Ding et al.developed polymer donor D18 and its outstanding derivatives[7−10],and the D18:Y6 cells gave a PCE of 18.22%[7],which was the first time for OSCs to deliver PCEs over 18%.

Synthesis and Crystal Structure of Bis(S-methyl-β-N- (4-dimethylaminophenyl)methlenedithiocarbazate) Nickel (Ⅱ)

Reaction of nickel (Ⅱ) acetate with S-methyl-β-N-(4 dimethy-laminophenyl) methlenedithiocarbazate gave a mononuclear complex [Ni (C11H14N3S2)2]. Crystal of the title compound belongs to monoclinic systern,space group C2/cwith cell parameters a= 18. 785 (1), b= 17. 274 (1 ), c= 8. 344 (1 ) A, β= 108. 64(2)°, V= 2565(1 ) A3, Z=4, Mr= 563. 36, Dc= 1. 459 g/cm3; μ=10. 05 cm-1 andF(000) = 1176. The final refinement with 2179 observed reflections is converged withR= 0. 044 and R.= 0. 069. X-ray crystal structure analysis revealed that the coordina-tion geometry of Ni (Ⅱ) is a square-planar with two equivalent Ni -N and Ni - Sbonds. The Schiff-base ligand loses a proton from its tautomeric thiol form and is coor-dinated to the nickel atom via the mercapto sulphur and the β-nitiogen.

Single photon emitters originating from donor-acceptor pairs

Starting from the groundbreaking work in graphene[1],the active research in two-dimensional(2D)layered materials has unveiled a number of exotic phenomena that are unique in the 2D limit.In addition to the semimetal graphene,the semiconducting transition metal dichalcogenides(TMDs)and the insulating hexagonal boron nitride(hBN)are also the main driving forces of the field.

Synthesis, Crystal Structure and Properties of a New Cadmium Compound with(1,1？-(1,4-Butanediyl)bis(imidazole) and p-Hydroxybenzoic Acid

A new metal-organic framework based on bbi and PHBA（bbi = 1,1＇-（1, 4-butanediyl）bis（imidazole）, PHBA = p-hydroxybenzoic acid）, namely, [Cd（bbi）（PHBA）2]n（1） has been synthesized by the conventional method. Compound 1 displays a two-dimensional（2D） layer structure possessing the left-and right-handed helical chains and stabilized by intermolecular hydrogen-bonding to form a three-dimensional（3D） supramolecular structure. Topologically, the 2D layer belongs to well-known（4,4） network topology. The structure has been determined by single-crystal X-ray diffraction analyses, and further characterized by infrared spectra（IR）, elemental analyses and powder X-ray diffraction. In addition, the thermal behavior and luminescent properties of [Cd（bbi）（PHBA）2]n have been investigated in detail.

Synthesis and Cation-Mediated Electron Transfer in Fluorescence Quenching of Donor-Acceptor Podands

Reduced rate constants of photoinduced electron transfer in intramolecular fluorescence quenching of donor-acceptor podands induced by cation-complexation are observed in the highly exothermic reactions.

Synthesis and Crystal Structure of 10-Phenyl-1,7-dithia-4-oxa-10-aza-12-crown-4

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Donor‐acceptor carbon nitride with electron‐withdrawing chlorine group to promote exciton dissociation

Carbon nitride(C_(3)N_(4))is promising for photocatalytic hydrogen production,but photogenerated electrons and holes in C_(3)N_(4)usually tend to exist as excitons due to intrinsic Coulomb interactions making its photocatalytic activity unsatisfactory.Herein,a well‐designed intramolecular C_(3)N_(4)‐based donor‐acceptor(D‐A)photocatalytic system was constructed to promote exciton dissociation.Due to its good chemical compatibility with melamine and appropriate sublimation property,2‐amino‐4,6‐dichloropyrimidine unit was chosen as the monomer to react with melamine to construct intramolecular D‐A system(CNCl_(x)).The hydrogen evolution rate of CNCl_(0.15)is 15.3 times higher than that of bulk C_(3)N_(4)under visible light irradiation,with apparent quantum efficiency of 13.6%at 420 nm.The enhanced activity is attributed to introduced electron‐withdrawing−Cl group as terminal group in the resulted CNCl_(x) samples,which can build internal electric field to promote the exciton dissociation into free electron and hole.In addition,lower work function value of CNCl_(x) samples indicates that internal electric field can help free electrons and holes transfer to the surface of CNCl_(x) samples for photocatalytic reaction.

Synthesis, Structure of a Symmetrically Substituted Stilbene with Strong Two-photon Absorption and Up-converted Blue Fluorescence

Efficient Ti-catalyzed reductive coupling methodology was first employed to synthesize the symmetrical bis-donor stilbene, trans-4, 4'-bis[diphenyl amino] stilbene (BDPAS). X-ray diffraction analyses reveal that this new crystal belongs to the triclinic crystal system of centro-symmetric P-1 space group. The DBPAS solution, with the linear transmission at wavelength of greater than or equal to 450 nm, possesses large two-photon absorption cross section as high as 39.4x10(-48) cm(4).s/photon resulting in strong two-photon induced blue fluorescence of 460 nm, pumped by 740 nm laser irradiation.

DFT and TD-DFT Calculations of Orbital Energies and Photovoltaic Properties of Small Molecule Donor and Acceptor Materials Used in Organic Solar Cells

DFT and TD-DFT calculations of HOMO and LUMO energies and photovoltaic properties are carried out on four selected pentathiophene donor and one IDIC-4F acceptor molecules using B3LYP and PBE0 functionals for the ground state energy calculations and CAM-B3LYP functional for the excited state calculations.The discrepancy between the calculated and experimental energies is reduced by correlating them with a linear fit.The fitted energies of HOMO and LUMO are used to calculate the Voc of an OSC based on these donors and acceptor blend and compared with experimental values.Using the Scharber model the calculated PCE of the donor-acceptor molecules agree with the experiment.It has been found that fluorine substitution can be used to improve charge transport by reducing the electron and hole reorganization energies of the molecules.It is also found that the introduction of fluorine onto the donor pentathiophene unit of the donor molecule results in a change of polarity of the distributed charges in the molecule due to the high electronegativity of the fluorine atom.The quantum chemical potential(μ),chemical hardness(η)and electronegativity(χ),and electrostatic potential maps(EPMs)are also calculated to identify different charge distribution regions in all five molecules.

High Responsivity Organic Ultraviolet Photodetector Based on NPB Donor and C60 Acceptor

We report fabrication and characterization of organic heterojunction UV detectors based on N,N＇-bis（naphthalen- 1-y1）-N,N＇-bis （phenyl） benzidine （NPB） and fullerene C60. The effects of different thicknesses of NPB and C60 layers are studied and compared. Notably, the optimal thicknesses of electron acceptor C60 and electron donor NPB are 40 nm and 80 nm, respectively. The J V characteristic curves of the device demonstrate a three-order- of-magnitude difference when illuminated under a 350nm UV light and in the dark at -0.5 V. The device exhibits high sensitivity in the region of 320-380nm with the peak located around 35Onm. Especially, it shows excellent photo-response characteristic with a responsivity as high as 315 mA/W under the illumination of 192μW.cm 2 350nm UV light at -5 V. These results indicate that the NPB/C60 heterojunction structure device might be used as low-cost low-voltage UV photodetectors.

Synthesis and Crystal Structure of (E)-[1-Ferrocenyl-2-(4-Chlorophenyl) ethylene]

The single crystal structure of the donor-acceptor ferrocenyl derivativeC18H15ClFe (Mr = 322. 62 ) has been determined, belonging to orthorhombic crystalsystem, space group P212121 with lattice parameters a= 11. 307 (2), b= 8. 471 (2 ), c=15. 427(3) A, V= 1477. 7(9) A3, Z=4, D.= 1. 45 g. cm-3, λ(MoKα) =0. 71073A,μ= 11. 9 cm-1, F(000) = 664. The final R value for 1534 observed [I>3σ(I)] reflec-tions is 0. 060. The configuration of the C =C double bond is trans. The C5H4CH =CHC6H4Cl fragrnent is almost planar. The rings of ferrocene are almost in the eclipsedpositions with each other.

Comparison of conventional and inverted structures in fullerene-free organic solar cells

A n-type small molecule DC-IDT2E with 4,4,9,9-tetrakis（4-hexylphenyl）-indaceno[1,2-b：5,6-bt]dithiophene as a central building block, furan as rr-bridges, and 1,1 -dicyanomethylene-3-indanone as end acceptor groups, was synthesized and used as an electron acceptor in solution-processed organic solar cells （OSCs）. DC-IDT2F exhibited good thermal stability, broad and strong absorption in 500-850 rim, a narrow bandgap of 1.54 eV, LUMO of-3.88 eV, HOMO of-5.44 eV and an electron mobility of 6.5 × 10-4 cm2/（V.s）. DC-IDT2F-based OSCs with conventional and inverted structures exhibited power conversion efficiencies of 2.26 and 3.08% respec- tively. The effect of vertical phase separation and morphology of the active layer on the device performance in the two structures was studied.

Lithium Salt of NH_2-substituted Graphene Nanoribbon with Twofold Donor-acceptor Framework: Large Nonlinear Optical Property

Based on graphene, a new class of second-order nonlinear optical（NLO） material, the lithium salt of NH2-substituted graphene nanoribbon with the twofold donor（D）/acceptor（A） mode, was reported. Eight stable 2Li-2NH2-GNR lithium salts, especially cis lithium salts, display considerably large β0 values. The combination of NH2-substituting and cis Li-doping makes β0 greatly increased from 0（GNR） to 1.2×105―2.9×105 a.u.（cis-2Li- 2NH2-GNRs）. Our largest β0 value（2.9×105 a.u.） for cis-2Li-1,3-2NH2-AGNR is comparable to the record value of 1.7×105 a.u. for a long donor-acceptor polyene.

Phenomenon of Mutual Compensation of Radiation Donors and Acceptors and Creation of Radiation-Resistant Materials

The phenomenon of mutual compensation of radiation donors and acceptors is discovered in IrtAs-InP solid solutions. This phenomenon is a result of opposite directed radiation processes, taking place in the irradiated InAs-InP solid solutions. The radiation creates donor type defects in the sublattice of InAs and electrons concentration increases. The contrary process occurs in the sublattice of InP. Radiation originates acceptor type defects and the carrier concentration decreases. The noted effect is going on in the all alloy composition. Exact mutual compensation of radiation donors and acceptors is achieved by selecting of the alloys definite composition. As a result, the main parameter of semiconductors-electrons concentration remains constant even under the hard radiation with fluences of Ф = 2 × 10^18 fast neutrons/cm^2. So there has been created radiation-resistant material.

Theoretical Studies on the First Hyperpolarizabilities of One-dimensional Donor-bridge-acceptor Chromophores

The ground-state dipole moments and second-order nonlinear optical （NLO） properties of a series of one-dimensional （1D） chromophores with donor-bridge-acceptor （D-B-A） structures have been investigated by using the second-order MФller-Plesset （MP2） and density functional theory （DFT） methods with the basis set of 6-31＋G（d）. According to the calculated results, the relationship between the molecular static first hyperpolarizability （βμ） and the directions of electron transition has been summarized. In terms of the sign of βμ, these 1D organic chromophores were classified into two categories： type Ⅰ with negative βμ and type Ⅱ bearing positive βμ. The analyses show that the remarkable difference of the first hyperpolarizabilities between Ⅰ and Ⅱ chromophores is associated mainly with the electrostatic interaction between terminal groups and the transport electrons in excited states. Moreover, different from the popular viewpoint, the obtained results also show that most of this series of 1D D-B-A molecules are more charge-separated in the ground states than in the excited states. As a whole, this theoretical investigation, to some extent, can be considered as a useful reference in designing the NLO chromophores with large first hyperpolarizabilities.

Theoretical Studies on the First Hyperpolarizabilities of One-dimensional Donor-bridge-acceptor Chromophores and New Applications of BLA in Determining Molecular First Hyperpolarizabilities

We present a quantum-chemical analysis of the relationship between the bond length alteration （BLA） and the static first hyperpolarizability of a series of one-dimensional （1D） chromophores with donor-bridge-acceptor （D-B-A） structures. The calculated results show that the parameter BLA can be considered as an indicator to evaluate the molecular first hyper- polarizability. Along the direction of molecular ground-state dipole moments, the evolutions of BLA can be classified into three categories： the first is a non-monotonic line, which represents most chromophores; the second is monotonic increasing; and the third, contrarily, is monotonic decreasing. On the whole, the first hyperpolarizabilities of these studied chromophores are the monotonic functions of BLA along the direction of dipole moments. Therefore, the first hyperpolarizability of these 1D chromophores can be preliminarily evaluated in terms of the development of BLA without a rigorous computation. In other words, one can roughly estimate the relative magnitude of the first hyperpolarizability according to the optimized geometry.

用Reactor、Acceptor模式构建CORBA通信层

CORBA是一种面向对象的分布式计算环境 ,其核心部分是实现对象间的通信。为了构建通用性高、扩展性强的CORBA通信层 ,引入了Reactor模式、Acceptor模式。Reactor模式能以单进程来完成并发处理 ,而Acceptor模式有效地将服务初始化过程与服务处理过程相分离。首先阐述了Reactor模式、Acceptor模式的结构 ,包括 :句柄、同步事件多路分解器、初始分派器、具体事件处理器、Acceptor和服务处理器。然后讲述了该模式的运行过程 :如何建立连接以及如何处理服务。接着重点阐述了初始分派器、具体事件服务器、Acceptor和服务处理器的实现。并在此基础上说明了该模式的一个特性 :并发性 ;最后总结了该模式的优点和不足。