CAJ | 학술논문

采用密度泛函理论(DFT)-B3LYP/6-31G(d)方法对9,9'-螺双芴低聚物[(SBF)_n(n=1-4)]体系进行全优化,得到各分子的最高占据轨道(HOMO)和最低空轨道(LUMO)能量及HOMO-LUMO能隙,结果表明各分子整体表现出很好的共轭性质.并在分子的阳离子和阴离子状态的优化结构基础上,计算得到电离势(IP)、电子亲和势(EA)、空穴抽取能(HEP)、电子抽取能(EEP)和重组能等相关能量.利用单激发组态相瓦作用(CIS)/3-21G方法优化得到9,9'-螺双芴单体的S_1激发态的几何构型.用含时密度泛函理论(TD-DFT)方法计算得到了分子吸收光谱和荧光光谱的相关数据.随着聚合长度的增加,能隙变窄,空穴注入和电子转移的能力都相应提高,吸收光所需能量减小,吸收强度(f)增大,光谱红移.采用线性外推法,利用低聚物分子的各种性质与聚合度n之间的关系,得到高聚物的相应性质.为考察9位螺芴化的影响,将(SBF)_n的相关性质与母体芴的低聚物[(FL)_n(n=1-4)]进行比较,由两者的计算结果对比显示,在芴的9位螺芴化可以提高电子和空穴的传输能力,并同时保留芴优良的发光性质.
채용밀도범함이론(DFT)-B3LYP/6-31G(d)방법대9,9'-라쌍물저취물[(SBF)_n(n=1-4)]체계진행전우화,득도각분자적최고점거궤도(HOMO)화최저공궤도(LUMO)능량급HOMO-LUMO능극,결과표명각분자정체표현출흔호적공액성질.병재분자적양리자화음리자상태적우화결구기출상,계산득도전리세(IP)、전자친화세(EA)、공혈추취능(HEP)、전자추취능(EEP)화중조능등상관능량.이용단격발조태상와작용(CIS)/3-21G방법우화득도9,9'-라쌍물단체적S_1격발태적궤하구형.용함시밀도범함이론(TD-DFT)방법계산득도료분자흡수광보화형광광보적상관수거.수착취합장도적증가,능극변착,공혈주입화전자전이적능력도상응제고,흡수광소수능량감소,흡수강도(f)증대,광보홍이.채용선성외추법,이용저취물분자적각충성질여취합도n지간적관계,득도고취물적상응성질.위고찰9위라물화적영향,장(SBF)_n적상관성질여모체물적저취물[(FL)_n(n=1-4)]진행비교,유량자적계산결과대비현시,재물적9위라물화가이제고전자화공혈적전수능력,병동시보류물우량적발광성질.
9,9'-Spirobifluorene oligomers((SBF)_n(n=1-4)) were fully optimized using density functional theory(DFT) at the B3LYP/6-31G(d) level.We obtained the highest occupied molecular orbital(HOMO),the lowest unoccupied molecular orbital(LUMO) energies,and HOMO-LUMO energy gap from these DFT calculations.All molecules have good π conjugation structures.From the optimized geometries of the cationic and anionic charged states,we calculated the ionization potential(IP),electron affinity(EA),hole extraction potential(HEP),electron extraction potential(EEP),and the reorganization energy.The singlet excited geometry of 9,9'-spirobifluorene was calculated using the single-excitation configuration interaction(CIS)/3-21G method.Absorption and emission spectra were obtained by employing time-dependent(TD)-DFT calculations.Results show that as the lengths of oligomers increase,the HOMO-LUMO energy gaps become narrower,the hole injection and the electron transport propeaies improve,the lowest excitation energies decrease,the oscillator strength (f) increases,and the maximum absorption wavelengths(λ_(max)) show a red shift.The electronic and electrochemical properties of the polymer were predicted by extrapolating the properties of the oligomers with an infinite reciprocal chain length.To investigate the influence of substituting the 9 position of the fluorene,some parameters ofthe parent fluorene ((FL)_n(n=1-4)) were calculated for comparison.From this comparison,it is obvious that spiro-functionalization at the fluorene C-9 bridge position can greatly improve the electron and hole transport properties and the excellent emission spectral quality of the fluorene is maintained.