Highly efficient perovskite solar cells by tuning electronic structures of thienothiophene-based as hole transport materials

The atomic substitutions were used to study the hole transport materials (HTM) properties of six thiophenothiophene molecules (HTM1-HTM6) to reveal the relationship between their core structures and photoelectric properties. To better investigate the difference between experimentally original and designed molecules, we calculated the hole mobility and some parameters (such as energy levels, stability, and optical properties, etc). The results showed that the molecular orbital levels of the original and designed molecules have well matched with perovskite and Ag electrode to ensure hole transport and inhibit the electron reflux. Among the designed HTMs, HTM5 has the smallest energy gap that results in the red-shifted absorption spectra. Furthermore, there is an obviously increased charge transfer integral V due to the introduction of the Si atom, which greatly improved the hole mobility. Therefore, atom substitution by introducing Si atoms (HTM5) will improve the energy levels and charge transport ability, and molecular design by means of atom substitution can be a potential way to tunable HTM performance in solar cells.     

A giant enhancement of magnetic moment in a ternary three-shell icosahedral cluster: Fe@Mn12@Au20

ABSTRACT

The average magnetic moment per atom of Mn₁₃ cluster is expected to be enhanced by doping or coating with a shell. Several ternary core–shell icosahedral clusters TM@Mn₁₂@Au₂₀ were constructed by combining substituting the central Mn with VIII elements (Fe, Co, Ni, Ru, Rh, Pd and Pt) and coating with a icosahedral Au₂₀ shell, and systematically studied by using the first-principles density functional method. Compared to Mn₁₃, Fe@Mn₁₂@Au₂₀ cluster shows a giant enhancement on total magnetic moment (52?µ_B) which can be greatly attributed to the ferromagnetic coupling between spin moments of atoms. Coating with Au₂₀ shell enlarged the average distances of TM-Mn and Mn-Mn and is a useful way to change the magnetic coupling style. By analysis of density of states and electron localisation functional, we can conclude that the weak hybridisation between Fe and Mn in Fe@Mn₁₂@Au₂₀ is propitious to maintain their original direction of spin moments of atoms and then form ferromagnetic coupling.     

A periodic DFT study on adsorption of small molecules(CH_4,CO,H_2O,H_2S,NH_3)on the WO_3(001) surface-supported Au

Gas molecules(such as CH4,CO,H2O,H2S,NH_3)adsorption on the pure and Au-doped WO3(001)surface have been studied by Density functional theory calculations with generalized gradient approximation.Based on the the calculation of adsorption energy,we found the most stable adsorption site for gas molecules by comparing the adsorption energies of different gas molecules on the WO3(001)surface.We have also compared the adsorption energy of five different gas molecules on the WO3(001)surface,our calculation results show that when the five kinds of gases are adsorbed on the pure WO3(001)surface,the order of the surface adsorption energy is CO>H2S>CH4>H2O>NH3.And the results show that NH3 is the most easily adsorbed gas among the other four gases adsorbed on the surface of pure WO3(001)surface.We also calculated the five different gases on the Au-doped WO3(001)surface.The order of adsorption energy was found to be different from the previous calculation:CO>CH4>H2S>H2O>NH3.These results provide a new route for the potential applications of Au-doped WO3 in gas molecules adsorption.     

密度泛函理论研究MN@H_2O (M=Ga,Ge, In,Sn, Sb; N=M,Al)团簇的特性

采用密度泛函理论的B3LYP, B3P86, B1B95, P3PW91和PBE1PBE方法结合SDD, LANL2DZ和CEP-121G基组计算了d~(10)组态二聚物MN(M=Ga, Ge, In, Sn和Sb; N=M和Al)的几何结构.采用B3P86/SDD进一步研究了MN@H_2O团簇的几何结构及吸附能.结果表明,水分子结合在二聚物M_2上时,对二聚物影响较大,对水分子自身影响较小.将M_2中Ga, Ge, In, Sn或Sb替换一个原子为Al时,水分子在GeAl和SnAl上的吸附能变化较大,而在GaAl, InAl和SbAl上吸附能变化较小.另外, H_2O吸附在Ga, Ge, In, Sn和Sb上时,与吸附在Al上时,吸附能的变化不大.     

垂直旋转流场中单颗粒运动状态判别及受力分析

为研究单颗粒在旋转流场中的运动状态及受力情况,以毫米级球形颗粒为例,利用旋转流场颗粒运动装置,通过使用摄像机记录颗粒在流场中的运动轨迹以获取其运动参数,分析了不同转速和颗粒直径条件下颗粒的运动轨迹,拟合得到了颗粒运动状态判别公式以及颗粒运动轨迹公式,分析了颗粒在旋转流场中的受力情况。结果表明,颗粒在旋转流场平衡状态下运动状态主要分为两类,一类是未离开壁面保持静止,另一类是离开壁面保持稳定周向运动;颗粒进行周向运动的轨迹为椭圆形,并且圆心随着转速的增大靠近旋转中心,而随着粒径的增大靠近壁面;颗粒在旋转流场的运动过程中主要受到离心力和旋转科式力作用。     

具有连续偏差变元的二阶阻尼方程的振动定理

研究了一类具有连续偏差变元的二阶阻尼方程,得到该方程振动的新的判别准则.最后,还给出了2个例子说明本文的应用.     

动态组合化学最新进展

动态组合化学是组合化学的一个新兴分支,在药物先导化合物的发现中有广阔的应用前景。在动态组合化学库中,利用靶标分子的诱导结合作用,通过可逆共价反应,能够选择性的筛选到与靶标分子存在强相互作用的优势化合物。本文按照动态组合化学方法简介、动态组合化学中的可逆共价化学、动态组合化学库的分类、动态组合化学库筛选方法的研究进展及动态组合化学在药物先导化合物发现过程中的应用等5个方面对动态组合化学进行了概述。     

含能材料的密度、爆速、爆压和静电感度的理论研究

用密度泛函理论(DFT) B3LYP方法, 在6-31G*基组水平下, 全优化计算了系列硝胺类和硝基芳烃类爆炸物的几何构型, 用Monte-Carlo方法和自编程序, 基于0.001 e•bohr^－3等电子密度面所包围的体积空间求得分子平均摩尔体积(V)和理论密度(ρ). 用Kamlet-Jacobs方程基于理论密度(ρ)和PM3计算生成焓(ΔH_f)估算标题物的爆速(D)和爆压(p), 发现多环硝胺类化合物的爆轰性能优于芳烃硝基类化合物, 故此, 在寻求高能量密度材料(HEDM)时, 我们应特别关注多环硝胺化合物. 与ρ和D文献值比较, 表明本理论计算方法和结果是适用可靠的. 将爆速(D)和爆压(p)计算值与静电感度实验值(E_ES)进行比较和关联, 发现: 若对化合物进行细致分类讨论, 则它们之间存在较好的线性关系. 据此建议, 在含能材料分子设计中, 可通过理论计算爆轰性质(D或p)去预估难以定量求得或尚未合成的含能材料的静电火花感度值(E_ES). 此外, 我们还讨论了取代基对ρ, D和p的影响, 也有助于分子设计.