Morphology and efficiency enhancements of PTB7-Th:ITIC nonfullerene organic solar cells processed via solvent vapor annealing

The nanoscale morphology within the photoactive layer of organic solar cells is critical in determining the power conversion efficiency (PCE). Here, we draw attention to the roles of molecular arrangement, and domain size in improving performance, which can be tuned by subjecting the photovoltaic materials to solvent vapor annealing (SVA). In our PTB7-Th:ITIC devices, the PCE can be improved by exposing the device to solvent vapor for 60 s after solution casting. The solvent vapor prolongs reorganizational time and increases molecular ordering and domain size/phase separation, which are sub-optimal in pristine PTB7-Th:ITIC blend films. This improved morphology results in better charge mobility, reduced recombination, and ultimately an improved PCE from 7.1% to 7.9% when using CS2 as the annealing solvent. This simple SVA technique can be applied to a range of OPV systems where the molecular ordering is inferior within the as-cast photoactive layer.

Effect of dual annealing upon photovoltaic properties of polymer solar cells based on poly(3-hexylthiophene)

A dual annealing method comprised of toluene vapor treatment and post thermal annealing was employed to fabricate polymer solar cells （PSCs） based on poly（3-hexylthiophene） （P3HT） and [ 6,6 J-phenyl-C61-butyric acid methyl ester （PCBM） film. It is found that the P3HT crystallinity and chain ordering can be dramatically enhanced by this annealing process as compared with the films treated merely with solvent vapor annealing, which is verified by a higher X-ray diffraction intensity peak and clearly visible fibrillar crystalline domains of P3HT. The result suggests that a favorable e- quilibrium condition was established by dual annealing in the morphology reorganization. Due to the morphological improvement of active layer, the dually annealed PSCs show better overall perform- ances, with a mean power conversion efficiency of 4. 06% and an increase in each electrical parame- ter, than any solely annealed ones.

Annealing-enhanced interlayer coupling interaction in GaS/MoS2 heterojunctions

Fabrication of large-area atomically thin transition metal dichalcogenides is of critical importance for the preparation of new heterojunction-based devices.In this paper, we report the fabrication and optical investigation of large-scale chemical vapor deposition(CVD)-grown monolayer MoS2 and exfoliated few-layer GaS heterojunctions.As revealed by photoluminescence(PL) characterization, the as-fabricated heterojunctions demonstrated edge interaction between the two layers.The heterojunction was sensitive to annealing and showed increased interaction upon annealing at 300℃ under vacuum conditions, which led to changes in both the emission peak position and intensity resulting from the strong coupling interaction between the two layers.Low-temperature PL measurements further confirmed the strong coupling interaction.In addition, defect-related GaS luminescence was observed in our few-layer GaS, and the PL mapping provided evidence of edge interaction coupling between the two layers.These findings are interesting and provide the basis for creating new material systems with rich functionalities and novel physical effects.

Understanding the synergistic effect of mixed solvent annealing on perovskite film formation

Morphology control of perovskite films is of critical importance for high-performance photovoltaic devices. Although solvent vapor annealing(SVA) treatment has been widely used to improve the film quality efficiently, the detailed mechanism of film growth is still under construction, and there is still no consensus on the selection of solvents and volume for further optimization. Here, a series of solvents(DMF, DMSO, mixed DMF/DMSO) were opted for exploring their impact on fundamental structural and physical properties of perovskite films and the performance of corresponding devices. Mixed solvent SVA treatment resulted in unique benefits that integrated the advantages of each solvent, generating a champion device efficiency of 19.76% with improved humidity and thermal stability. The crystallization mechanism was constructed by conducting grazing-incidence wide-angle x-ray diffraction(GIWAXS) characterizations, showing that dissolution and recrystallization dominated the film formation. A proper choice of solvent and its volume balancing the two processes thus afforded the desired perovskite film. This study reveals the underlying process of film formation, paving the way to producing energy-harvesting materials in a controlled manner towards energy-efficient and stable perovskite-based devices.

Annealing effect and irradiation properties of HFCVD diamond films

The post-growth treatment of a [100]-oriented diamond film was performed to improve the film quality. The characteristic of post-growth film was investigated by using the RAMAN spectrum and the capacitance-frequency curve. The results show that the resistivities and frequency response enhance after the post-treatments in solution of H2SO4 and H2O2 and an annealing under N2 atmosphere at 500 ℃ for 60 min. Under a bias voltage of 100 V, the net photocurrent is obtained under 55Fe(5.9 keV) X-rays and 241Am (5.5 MeV) α particles radiation, respectively. The photocurrent increases rapidly at first and becomes stable for the “pumping” effect with the radiation time.

高温退火Cu(111)衬底上生长高质量厘米尺寸单晶石墨烯

二维(2D)石墨烯具有原子层厚度,在电子器件中展示出突破摩尔定律限制的巨大潜力。目前,化学气相沉积(CVD)是一种广泛应用于石墨烯生长的方法,满足低成本、大面积生产和易于控制层数的需求。然而,由于催化金属(例如Cu)衬底一般为多晶特性,导致CVD法生长的石墨烯晶体质量相对较差。为此,通过高温退火工艺制备了Cu(111)单晶衬底,使石墨烯的初始成核过程得到了很好的控制,从而实现了厘米尺寸的高质量单晶石墨烯的制备。根据二者的晶格匹配关系,Cu(111)衬底为石墨烯生长提供了唯一的成核取向,相邻石墨烯成核岛的边界能够缝合到一起。单晶石墨烯具有高电导率,相较于原始多晶Cu上生长的石墨烯(1415.7Ω·sq^(-1)),其平均薄层电阻低至607.5Ω·sq^(-1)。高温退火能够清洁铜箔,从而获得表面粗糙度较低的洁净石墨烯。将石墨烯用于场效应晶体管(FET),器件的最大开关比为145.5,载流子迁移率为2.31×10^(3)cm^(2)·V^(-1)·s^(-1)。基于以上结果,相信本工作中的单晶石墨烯还满足其他高性能电子器件的制备。

Solvent Vapor Annealing Induced Polymorphic Transformation of Polybutene-1

Solvent annealing is a facile method for changing the aggregated microstructure and physical properties of polymer materials. In this paper, we addressed the effects of solvent vapor annealing, including chloroform and water vapor, on the polymorphic transformation in both hot-pressed film and electrospun nonwoven of isotactic polybutene-1 （PB-1） by means of in situ Fourier transform infrared spectroscopy （FTIR）. The pretty rapid transition rate caused by the increased motion of molecular chains under chloroform vapor is associated with a lowest crystallinity. Also, a decreased crystallinity with the crystal transition occurred in electrospun nonwovens resulting from the relaxation of the stretched molecular chains into amorphous state rather than realignment into crystal form I predominating the crystal transition process.

添加剂和溶剂退火协同优化制备高性能厚膜有机太阳能电池

通过溶剂添加剂1-氯萘(CN)和二硫化碳(CS_2)溶剂退火(SVA)协同优化了基于窄带隙小分子受体的厚膜活性层形貌,揭示了该策略对共混膜形貌的调控机理,研究了其对活性层中的载流子动力学以及器件光伏性能的影响.结果表明,CN添加剂可以有效促进受体材料结晶聚集,CS_2溶剂退火能够进一步提升活性层材料分子堆积的有序性,同时优化给受体材料相分离尺寸,降低共混膜表面的粗糙度,实现了良好的纳米尺寸相分离形貌.基于CN+SVA处理的PM6∶Y6厚膜(300 nm)器件的电荷传输和复合性质得到改善,取得了15.23%的光电转换效率(PCE),显著高于未经处理(PCE=11.75%)和仅用CN处理(PCE=13.48%)的光伏器件.该策略具有良好的适用性,将基于PTQ10∶m-BTP-PhC6器件的光伏性能从13.22%提升至16.92%.

原子气室玻壳残余应力消除方法研究

原子气室作为量子仪表的核心部件,其稳定性和寿命是决定量子仪表长期可靠工作的主要因素。在制备原子气室过程中,玻璃高温熔接产生的残余应力会影响气室的力学特性及光学性能,应力过大将导致气室在加工过程中发生炸裂,并在后期应力释放过程中出现裂纹,造成气室失效。测量和消除原子气室玻壳残余应力对提高原子气室的寿命和可靠性有重要意义。利用双折射应力测量仪对原子气室玻壳应力分布进行无损测量,测量结果具有良好的一致性和重复性。经过退火处理后,5支玻壳的应力最大值、平均值和标准差的平均值降幅分别达到81.35%、75.67%和77.32%,表明消除应力取得了良好的效果。

Synergistic Effects of External Electric Field and Solvent Vapor Annealing with Different Polarities to Enhance β-Phase and Carrier Mobility of the Poly(9,9-dioctylfluorene)Films

In this work,the synergistice efects of external electric field(EEF)and solvent vapor annealing to enhanceβ-phase and carrier mobility of poly(9,9-dioctylfuorene)(PFO)films were investigated.It is found that EEF can promote the PFOβ-phase conformation transition and orientate the PFO chains along the EEF direction with the as-sistance of polar solvent vapor annealing.PFO chain orderness is closely related to the solvent polarity.In particular,the B-phase content in the annealed film of strong polar chloroform vapor increases from 18.7%to 34.9%after EEF treatment.Meanwhile a characteristic needle-like crystal is formed in the flm,as a result,the hole mobility is en-hanced by an order of magnitude.The mechanism can be attributed to the fast polarization of solvent dipole under the action of EEF,thus forming a driving force that greatly facilitates the orientation of PFO dipole unit.Research also reveals that EEF driving of the PFO chains does not occur with an insoluble solvent vapor since the solvent molecules cannot swell the film,thus there is insufficient free volume for PFO chains to adjust their conformation.This research enriches the understanding of the relationship between solvent vapor annealing and EEF in orientation polymers,and this method is simple and controlled,and capable of integrating into large-area thin film process,which provides new insights to manufacture low-cost and highly ordered polymer films,and is of great significance to enhance carrier mobility and efficiency of photoelectric devices based on polymer condensed matter physics.

芴-苯并噻二唑荧光分子压致变色特性研究

本文研究了不同后处理工艺对结晶性荧光有机小分子二(9,9-二甲基-芴)-2,1,3-苯并噻二唑(FBTF)的光致发光性能的影响。实验结果表明:FBTF粉末经重复研磨和加热处理后,出现了绿光-黄光-绿光的可逆光致发光现象。XRD测试表明,FBTF粉末原样具有较好的分子堆积有序性;经研磨后FBTF分子的堆积有序性遭到破坏,使得具发光光谱出现红移;加热处理后FBTF分子堆积的有序性得到有效改善,其发光光谱出现明显的蓝移。随后,利用不同极性的溶剂对FBTF薄膜进行溶剂蒸汽处理,FBTF薄膜发光光谱出现明显的蓝移,随着溶剂的溶解性增加FBTF的发光光谱蓝移幅度也随之增加。

^(60)Co Gamma Irradiation and Annealing Effects on Transport Properties of Antimony Telluride Platelets Grown by Physical Vapor Deposition

Physical vapor deposition method was employed to deposit antimony telluride （Sb2Te3） crystals in a dual-zone furnace. The microstructure, surface topography and composition of samples were characterized using X-ray diffraction, atomic force and scanning electron microscopy. Seebeck coefficient （Sic）, electrical conductivity （σ⊥c） as well as power factor （PF） were enhanced for pure Sb2Te3 samples upon annealing, and the samples annealed at 473 K exhibited the highest PF of 3.16 × 10^-3 W m-1K-2 with an enhancement of 22% in the figure of merit （Z）. When the delivered dose of 60Co gamma radiation was increased from 0 to 30 kGy in the stoichiometric crystals, σ⊥c decreased due to the decrease in mobility. As a result of the increase in S, PF and Z improved by 12.11 and 13.7%, respectively, in the 30 kGy gamma- irradiated crystals. Both RH （BIIc） and S⊥c were positive, suggesting that the prepared Sb2Te3 crystals retained the p-type semiconductivity after these treatments.

Te vapor annealing of indium-doped CdMnTe crystals

Thermal annealing in Te vapor atmosphere was adopted to improve the properties of indium-doped Cd_(1-x)Mn_xTe(x=0.2,CdMnTe) wafers grown by the vertical Bridgman method.The wafers before and after annealing were characterized by measuring the Te inclusions,etch pit density(EPD),Mn composition,resistivity, and impurity.IR transmission microscopy and EPD measurements revealed that the densities of Te inclusions reduced from(5-9)×10~4 cm^(-3) to(2-4)×10~4 cm^(-3) and EPD from 10~5 cm^(-2) to 10~4 cm^(-2) after annealing. NIR transmission spectroscopy showed that the Mn composition increased by 0.002-0.005 mole fractions during the annealing.The resistivity of the wafers improved from(2.0-4.5)×10~8Ω·cm to(1.7-3.8)×10~9Ω·cm,which suggested that the deep-level donor of Te antisites was successfully introduced after annealing.Inductively coupled plasma-mass spectrometry(ICP-MS) revealed that the concentrations of impurities in the wafer decreased,which indicated the purifying effects of Te vapor annealing on the wafers.All the results demonstrate that the Te vapor annealing of the indium-doped CdMnTe crystal has positive effects on the crystallinity,resistivity and purity of CdMnTe wafers.

Controlling PCBM aggregation in P3HT/PCBM film by a selective solvent vapor annealing

A selective solvent vapor, i.e., cyclohexanone or isopropyl benzene, which is a poor solvent for poly(3-hexylthiophene-2,5-diyl) (P3HT) and a good solvent for fullerene derivative [6,6]-phenyl-C61-butyric acid methyl ester (PCBM), was employed to reduce the size of PCBM aggregates and prolong the formation time of big PCBM aggregates in P3HT/PCBM film. PCBM nucleates and aggregates of 10-20 nm scale form in the first few minutes annealing. Then the size of PCBM aggregates kept unchanged until annealing for 60 min. Finally, larger PCBM aggregates of micron-size formed hours later. On the contrary, the growth rate of PCBM aggregates was faster and their size was larger when treated with a good solvent vapor for both components. The P3HT crystallinity was the same with different types of annealing solvents, although the rate of P3HT self-organization was decreased after a selective solvent vapor annealing. Because of the smaller size of phase separation, the device annealed in a selective solvent vapor for 30 min had a higher PCE than that annealed in a good solvent vapor.

γ-LiAlO_2晶体的退火研究

利用温度梯度法生长出了透明的γ LiAlO2 单晶 ,通过扫描电镜和X射线薄膜衍射分析了不同退火气氛对所切得的 ( 0 0 1 )晶片表面结构的影响。结果表明 :1 1 0 0℃ / 70h空气和真空中的退火处理使γ LiAlO2 晶片表层变成LiAl5O8多晶 ,而同温度富锂气氛退火可以有效地抑制锂的挥发 。

退火对Ga_2O_3薄膜特性的影响

采用金属有机物化学气相沉积法在c面蓝宝石衬底上生长了高质量的β-Ga_2O_3薄膜,并将样品分别在真空、氧气、氮气氛围下退火30 min,研究了各类退火工艺对Ga_2O_3薄膜特性的影响,对退火所得的薄膜进行了X射线衍射、光致发光谱、紫外透射谱和原子力显微镜扫描的研究。结果表明,各类退火工艺均能够优化薄膜的晶体质量和表面形貌,同时有效改善了薄膜的光学性质。其中,氧气退火后的样品在可见光波段透射率高达83%,且吸收边更加陡峭;表面粗糙度降至0.564 nm,其表面更为平整。这些结果说明氧气退火对晶体质量的提高最为显著。氮气、真空退火的样品在光致发光谱中出现365 nm的发光峰,这是大量氧空位的存在导致的。

退火对氟化类金刚石膜结构及电学性能的影响

以CF4和CH4为源气体,在不同的温度和功率下,使用射频等离子体增强化学气相沉积(RF-PECVD)法制备氟化类金刚石(F-DLC)薄膜,并在Ar气中进行退火处理。利用椭偏仪、X射线衍射仪、傅里叶变换红外光谱(FTIR)、拉曼光谱仪(Raman)以及QS电桥对薄膜厚度、结构以及电学性质进行表征。研究结果表明:在退火温度为300℃时,薄膜很稳定;退火温度达到400℃时,大部分H从膜内逸出,C—Hx(x=1,2,3)化学键基本消失,C—Fx,C=C和C=O等化学键的相对含量发生改变;薄膜的介电常数与薄膜内F的含量有关,退火使F的含量减少,介电常数增大。

多晶硅薄膜太阳电池

多晶硅薄膜太阳电池因兼具低材料消耗、低成本、高稳定性及多晶硅薄膜微电子器件的成熟工艺而备受瞩目。对多晶硅薄膜太阳电池的结构和制备工艺流程进行了详细阐述,指出当前多晶硅薄膜太阳电池的关键研究方向,即衬底的选择和高质量多晶硅薄膜的实现。特别是针对高质量多晶硅薄膜的制备,系统地介绍了化学气相沉积(CVD)、磁控溅射(MS)、固相晶化(SPC)、激光晶化(LC)以及快速热退火(RTA)等制备方法的工作原理、特点和优劣。综合阐述了各项技术的发展现状,并对上述技术及其在多晶硅薄膜太阳电池中的应用前景进行了客观评述与展望。

未掺杂CdZnTe与掺铟CdZnTe晶体的热处理

对于未掺杂 Cd0 .9Zn0 .1 Te晶片 ,采用在 Cd/ Zn气氛下 ,以 In作为气相掺杂源进行热处理 ;而对于低阻In- Cd0 .9Zn0 .1 Te晶片 ,则采用在 Te气氛下进行热处理 .分别研究了不同的热处理条件 ,包括温度、时间、p In或 p Te等对晶片电学性能、红外透过率以及 Te夹杂 /沉淀相的影响 .结果表明 ,在 Cd/ Zn气氛下适当的掺 In热处理和在 Te气氛下适当的热处理均有效地提高了晶片的电阻率 ,分别达到 2 .3× 10 1 0 和 5 .7× 10 9Ω· cm。

纳米Ti-Si-N薄膜的高温热稳定性

用直流等离子体增强化学气相沉积(PCVD)方法在不锈钢基体上制备了Ti-Si-N硬质纳米复合薄膜,研究了Si含量对薄膜硬度的影响及高温退火对薄膜晶粒尺寸及其硬度的影响.结果表明:薄膜的硬度随着Si含量的增加有先增大后减小的趋势,最大硬度可达70 GPa以上.薄膜表现出了较高的热稳定性能,对于晶粒尺寸在4 nm以下的薄膜,Ti-Si-N薄膜的纳米结构和硬度可以维持在1000℃以上.沉积态薄膜的品粒尺寸是影响薄膜再结晶温度的主要因素.薄膜的高热稳定性是由于沉积过程中发生的自发调幅分解形成了纳米复合结构,偏析使得纳米晶晶界具有强的热力学稳定性.