脉冲光场作用下啁啾双光子量子特性研究

基于量子理论和非线性光学,研究了脉冲光场作用啁啾准相位匹配非线性晶体的第Ⅱ类自发参变下转换过程中,脉冲宽度和啁啾系数对产生的纠缠双光子特性及Hong-Ou-Mandel(HOM)量子干涉结果的影响。结果表明,啁啾系数一定时,随着脉冲宽度的增加,双光子谱的不可区分性降低,HOM量子干涉可见度下降。当脉冲宽度一定时,随着啁啾系数的增加使双光子谱带宽增加,HOM量子干涉陷落变窄,双光子谱的不可区分性增强,从而提高了相干精度和干涉可见度。理论上得到了超宽带的双光子谱和对应超窄的HOM量子干涉图。     

甲基丙烯酸甲酯-甲基丙烯酸无规共聚物的合成及其在乳液聚合中的应用

通过自由基共聚制备了不同组成的甲基丙烯酸甲酯-甲基丙烯酸无规共聚物,用碱中和后作为大分子乳化剂用于乳液聚合.研究了无规共聚物的组成、用量及反应温度对乳液聚合的影响.结果表明,在相同的反应条件下,乳化剂中聚甲基丙烯酸含量越多,乳液聚合速率越快;同一乳化剂,随乳化剂浓度的增加,乳液聚合速率增加;在乳化剂组成、浓度不变的情况下,反应温度越高,乳液聚合速率越大.     

Low bandgap π‐conjugated copolymers based on fused thiophenes and benzothiadiazole: Synthesis and structure‐property relationship study

A series of low bandgap conjugated polymers consisting of benzothiadiazole alternating with dithienothiophene (DTT) or dithienopyrrole (DTP) unit with or without 3‐alkylthiophene bridge have been synthesized. Effect of the fused rings and 3‐alkylthiophene bridge on the thermal, optical, electrochemical, charge transport, and photovoltaic properties of these polymers have been investigated. These polymers show broad absorption extending from 300 to 1000 nm with optical bandgaps as low as 1.2 eV; the details of which can be varied either by incorporating 3‐alkylthiophene bridge or by replacing DTT with DTP. The LUMO levels (?2.9 to ?3.3 eV) are essentially unaffected by the specific choice of donor moiety, whereas the HOMO levels (?4.6 to ?5.6 eV) are more sensitive to the choice of donor. The DTT and DTP polymers with 3‐alkylthiophene bridge were found to exhibit hole mobilities of 8 × 10^?5 and 3 × 10^?2 cm² V^?1 s^?1, respectively, in top‐contact organic field‐effect transistors. Power conversion efficiencies in the range 0.17–0.43% were obtained under simulated AM 1.5, 100 mW cm^?2 irradiation for polymer solar cells using the DTT and DTP‐based polymers with 3‐alkylthiophene bridge as donor and fullerene derivatives as acceptor. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 5498–5508, 2009     

Impact of Alkoxyl Tail of Fullerene Dyad Acceptor on Crystalline Microstructure for Efficient External Treatment-free Polymer Solar Cells with Poly(3-hexylthiophene) as Donor

A series of tri(alkoxyl)benzene-fullerene dyads(PCBB-Cn, n=4, 6, 8, 10, 12) with varied tri(alkoxyl) chain lengths was designed, synthesized and used as acceptor materials in polymer solar cells(PSCs). The five fullerene dyads possess similar absorption spectra in dilute solution, decreased glass-transition temperature(T_g) and gradually elevated lowest unoccupied molecular orbital(LUMO) energy levels from -3.87 eV to -3.73 eV with the increase of the alkoxy chain length. In the fabrication of PSCs with poly(3-hexylthiophene)(P3HT) as donor and the fullerene dyads as acceptor, PCBB-Cn with longer tri(alkoxyl) chains and lower T_g can induce crystalline structure of P3HT during spin-coating the photoactive layer at room temperature and form nanoscale phase separated interpenetrating network of P3HT:PCBB-Cn blend films, which results in the improvement of photovoltaic performance of PSCs. A power conversion efficiency of 3.03% for the PSCs based on P3HT:PCBB-C10 was obtained without thermal annealing or solvent annealing. The thermal and solvent annealing-free fabrication using the fullerene dyads as acceptor is very important for the roll to roll production of PSCs with flexible large area.     

Volatile Perovskite Precursor Ink Enables Window Printing of Phase-Pure FAPbI3 Perovskite Solar Cells and Modules in Ambient Atmosphere

Despite the great success of perovskite photovoltaics in terms of device efficiency and stability using laboratory-scale spin-coating methods, the demand for high-throughput and cost-effective solutions remains unresolved and rarely reported because of the complicated nature of perovskite crystallization. In this work, we propose a stable precursor ink design strategy to control the solvent volatilization and perovskite crystallization to enable the wide speed window printing (0.3 to 18.0 m/min) of phase-pure FAPbI₃ perovskite solar cells (pero-SCs) in ambient atmosphere. The FAPbI₃ perovskite precursor ink uses volatile acetonitrile (ACN) as the main solvent with DMF and DMSO as coordination additives is beneficial to improve the ink stability, inhibit the coffee rings, and the complicated intermediate FAPbI₃ phases, delivering high-quality pin-hole free and phase-pure FAPbI₃ perovskite films with large-scale uniformity. Ultimately, small-area FAPbI₃ pero-SCs (0.062 cm²) and large-area modules (15.64 cm²) achieved remarkable efficiencies of 24.32 % and 21.90 %, respectively, whereas the PCE of the devices can be maintained at 23.76 % when the printing speed increases to 18.0 m/min. Specifically, the unencapsulated device exhibits superior operational stability with T₉₀>1350 h. This work represents a step towards the scalable, cost-effective manufacturing of perovskite photovoltaics with both high performance and high throughput.     

一种杂环磺化聚芳醚腈酮质子交换膜材料的合成及表征

用含二氮杂萘酮结构类双酚DHPZ,3,3′-二磺酸钠基-4,4′-二氟二苯酮,2,6-二氯苯腈以及4,4′-二氟二苯酮,通过缩合共聚合反应合成了一系列不同磺化度、高分子量的磺化聚芳醚腈酮.聚合物特性粘数为0·58~2·0dL/g.用红外光谱(FT-IR),核磁共振谱(1H-NMR)表征了聚合物结构.用差示扫描量热仪(DSC)和热重分析仪(TGA)研究了聚合物的耐热性能,研究表明其玻璃化温度(Tg)可达352℃,5%热失重温度大于500℃.以N-甲基吡咯烷酮为溶剂,溶液浇铸法制备了聚合物膜,并测定了膜的溶胀率以及质子交换能力.结果表明,与Nafion膜相比,磺化聚芳醚腈酮膜在相同的质子交换能力条件下,溶胀率显著降低.     

双泵浦光子晶体光纤参量放大研究

利用光子晶体光纤在不同零色散波长附近具有不同色散的特性,研究了在零色散波长为780 nm和1550 nm附近的双泵浦光子晶体光纤参量放大过程.在780 nm附近,讨论了零色散波长变化对双泵浦光子晶体光纤参量放大的影响.数值模拟结果表明:当零色散波长发生微小的变化时,信号增益谱带宽会发生很大的变化.当两泵浦光之间的波长差值减小时,零色散波长的变化对参量放大的影响在很大程度上可以得到抑制,但是增益带宽会有一定的减小.依据这一原理,在1550 nm附近设计光子晶体光纤中的色散平坦光纤参量放大,在5 m长的光子晶体光纤中,当峰值功率为10 W时,得到了增益为65 dB,带宽达到420 nm且极为平坦的增益谱.     

Synthesis and characterization of arylenevinylenearylene–naphthalene diimide copolymers as acceptor in all–polymer solar cells

Two n‐type conjugated D‐A copolymers, P(TVT‐NDI) and P(FVF‐NDI) with thienylene‐vinylene‐thienylene (TVT) or furanylene‐vinylene‐furanylene (FVF) as donor (D) units and naphthalene diimide (NDI) as the acceptor (A) units, were synthesized by the Stille coupling copolymerization. The two polymers possess good solubility, high thermal stability, and broad absorption bands with absorption edges at 866 nm for P(TVT‐NDI) and 886 nm for P(FVF‐NDI) . The LUMO energy levels of P(TVT‐NDI) and P(FVF‐NDI) are ?3.80 eV and ?3.76 eV respectively, so the two polymers are suitable for the application as acceptor in blending with most polymer donor in PSCs based on the energy level matching point of view. All polymer solar cells (all‐PSCs) were fabricated with P(TVT‐NDI) or P(FVF‐NDI) as acceptor and medium bandgap polymer J51 as donor for investigating the photovoltaic performance of the two n‐type conjugated polymer acceptors. And higher power conversion efficiency of 6.43% for P(TVT‐NDI) and 5.21% for P(FVF‐NDI) was obtained. The results indicate that arylenevinylenearylene–naphthalene diimide copolymer are promising polymer acceptor for all–PSCs. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017 , 55 , 1757–1764     

PPV衍生物的激发态动力学特性研究

利用共振飞秒光学克尔效应研究了C10－PPV溶液的非线性光学响应。实验结果表明，在共振激发条件下，C10－PPV挑学克尔效应信号表现为快速上升和随后的驰豫过程，其驰豫过程由两部分组成，一个200fs的快过程和一个400ps的慢过程。通过比较C10－PPV和掺杂C60后的C10－PPV荧光光谱，400ps的慢过程可归属为聚合物链内单重态激子在不同共轭段间的迁移过程。