【Adv.Mater.】西安近现代化学研究所高潮|突破20.73%效率与1600小时长寿命！液晶工程实现有机太阳能电池动力学与热力学协同调控
【Adv.Mater.】西安近现代化学研究所高潮|突破20.73%效率与1600小时长寿命！液晶工程实现有机太阳能电池动力学与热力学协同调控
文章标题：Synergistic Regulation of Crystallization Kinetics and Thermodynamics by Liquid Crystal Engineering Enables Efficient and Stable Organic Solar Cells
文章作者：Shujuan Liu, Lunbi Wu, Sha Liu, Weiping Wang, Zezhou Liang, Wenbo Yang, Jianxiang Yuan, Xiaojian Zhang, Yuchen Zhou, Jian Li, Chao Gao
文章概要
针对有机太阳能电池中活性层结晶动力学与热力学稳定性难以兼顾的瓶颈，研究团队创新性地引入向列相液晶分子3UTPP4进行协同调控。该策略不仅彻底消除了受体分子的冷结晶亚稳态，延缓了成膜过程以优化聚集结构，还显著抑制了非辐射复合损失并提升了载流子迁移率。基于该策略，PM6
引言
有机太阳能电池因具备轻薄、柔性与可溶液加工等优势而备受关注。近年来，非富勒烯受体材料的快速发展推动了器件效率跨越20%的大关，但在长期运行稳定性方面仍面临严峻挑战。以Y系列为代表的受体分子兼具小分子与高分子的复杂物理特性，在快速成膜过程中易被截留在深淬灭的热力学亚稳态中（常表现为明显的冷结晶峰）。在工作环境的光热应力驱动下，这种亚稳态会发生自发结构弛豫与过度聚集，从而诱发微观相分离恶化与非辐射复合损失。因此，在成膜过程中同时调控结晶动力学速率并锁定热力学稳态构型，是实现高效兼具高稳定性有机光伏器件的关键科学难题。
主要实验及结论
如图1所示，研究团队选用具有宽温区向列相且光学透明的商用液晶分子3UTPP4作为功能添加剂。差示扫描量热测试证实，3UTPP4的引入彻底消除了BTP-eC9在192.27°C附近的冷结晶峰，分子动力学模拟进一步揭示3UTPP4通过适度的非共价相互作用预先引导了受体分子规整排布，促使活性层在成膜阶段直接完成高效结晶，有效规避了淬灭亚稳态。如图2所示的原位吸收光谱表明，3UTPP4将共混膜的液-固转变时间由114 ms延长至166 ms，为分子自组装提供了充裕的时间；二维掠入射广角X射线散射进一步证明薄膜的面外–堆积距离显著缩短且晶体相干长度明显增加。结合如图3所示的原子力显微镜与透射电镜表征，改性后的薄膜展现出更分明的原纤网络和约20 nm的适宜相分离尺寸，为高效电荷传输构建了顺畅互穿的微观通道。
Fig.1 (a) Chemical structure of PM6, BTP-eC9 and 3UTPP4. (b) DSC plots of 3UTPP4. (c) POM images of 3UTPP4 at 90°C. (d) DSC plots of PM6 and PM6<3utpp4>, BTP-eC9 and BTP-eC9: 3UTPP4, PM6: BTP-eC9, and PM6: BTP-eC9: 3UTPP4 blend. (e) Normalized UV–vis-NIR absorption spectra of PM6, PM6<3utpp4>, BTP-eC9, and BTP-eC9<3utpp4> films. (f) The absorption coefficient of BTP-eC9 and BTP-eC9: 3UTPP4.
Fig.2 The in situ absorption of (a) PM6: BTP-eC9 and (b) PM6: BTP-eC9: 3UTPP4 films. (c) Time evolution of BTP-eC9 peak positions of PM6: BTP-eC9 and PM6: BTP-eC9: 3UTPP4. 2D GIWAXS patterns of (d) PM6: BTP-eC9 and (e) PM6: BTP-eC9: 3UTPP4 films. (f) 1D line-cuts of related 2D GIWAXS patterns. (g) (010) stacking distance. (h) (100) stacking distance.
Fig.3 AFM phase images of (a) PM6 and PM6: 3UTPP4 films; (b) BTP-eC9 and BTP-eC9: 3UTPP4 films; (c) PM6: BTP-eC9 and PM6: BTP-eC9: 3UTPP4 films. (d) TEM images of PM6: BTP-eC9 and PM6: BTP-eC9: 3UTPP4. The corresponding statistical fiber size distribution diagrams of (e) PM6, (f) PM6: BTP-eC9, (g) PM6: BTP-eC9 and (h) PM6: BTP-eC9: 3UTPP4. (i) Schematic diagram of 3UTPP4 regulation within active layer.
如图4所示，微观结构的优化显著提升了光伏输出特性。引入3UTPP4后，PM6
Fig.4 J–V characteristics of PM6: BTP-eC9 and PM6: BTP-eC9: 3UTPP4 devices. (b) EQE spectra of the corresponding devices. (c) Histogram of the PCEs for 25 devices. (d) Jph-Veff relationships. (e) Relationship of VOC vs Plight. (f) The dark current density. (g) Calculated hole and electron mobilities. (i) Dielectric constant of the devices.
Fig.5 2D contour maps of temperature varied steady-state PL spectra of (a) PM6: BTP-eC9 and (b) PM6: BTP-eC9: 3UTPP4 films. (c) FWHM of the steady-state PL spectra as a function of temperature for PM6: BTP-eC9 and PM6: BTP-eC9: 3UTPP4. The HS-EQE and EL curves of (d) PM6: BTP-eC9 and (e) PM6: BTP-eC9: 3UTPP4 devices. (f) EQEEL of PM6: BTP-eC9 and PM6: BTP-eC9: 3UTPP4 devices. (g) Summarized energy loss parameters. (h) Storage stability (25°C, N2) and (i) Photothermal stability (MPP tracking at 1 sun illumination, 45°C, N2) of PM6: BTP-eC9 devices with/without 3UTPP4.
如图6所示，将3UTPP4与传统固体添加剂1,4-二碘苯（DIB）联合使用产生了显著的协同增效作用，DIB优化相分布均匀性，而3UTPP4主导消除冷结晶亚稳态，二者协同将PM6
Fig.6 (a) J–V curve and (b) EQE curve of PM6: BTP-eC9 with 3UTPP4 and DIB. (c) The versatility of 3UTPP4 in several donor
总结及展望
本工作提出了一种通过商用向列相液晶分子协同调控成膜动力学与热力学稳态的通用策略，从根源上解决了有机受体冷结晶诱发的形态不稳定性问题。依托显示产业成熟丰富的液晶分子资源库，该研究不仅为设计制备兼具超高转换效率与长久运行寿命的有机光伏组件开辟了新途径，也为推动有机太阳能电池的大面积产业化应用奠定了坚实的实验与理论基础。
文章分享
如果这篇文章对你有帮助，欢迎分享给更多人！