Metallic nanoparticle ensemble, with narrow inter-particle distance, is a useful element for diverse optical devices due to highly enhanced electric field intensity at the gap. Self-assembly of block copolymer (BCP) can provide the versatile solution to fabricate precise nanostructures, but this methodology has the intrinsic limitation to realize optically coupled metallic multimer geometry with narrow inter-particle distance. This is because BCP-based nanotemplate possesses a minimum size limit for interparticle distance imposed by its thermodynamic restriction. Herein, we investigate the facile formation of metallic multimer with scalability and area-selectivity through the collapse of self-assembled BCP nanopattern. The capillary-force-induced collapse phenomenon enables a spatial transformation of lateral regular ordering in metallic nanoparticle array and enhances electric field intensity. The fabrication of this metallic nanoparticle ensemble from BCP lithography is successfully utilized for surface enhanced Raman scattering (SERS). The enhancement factor of metal nanoparticle multimer is calculated as ~6.74 × 10⁵ at 1000 cm⁻¹, 2.04 × 10⁶ at 1022 cm⁻¹, and 6.11 × 10⁶ at 1580 cm⁻¹, respectively.

中文翻译：

---

塌陷诱导的自组装纳米粒子的多聚体形成，用于表面增强拉曼散射

由于间隙处的电场强度大大提高，因此粒子间距离较窄的金属纳米粒子集合体是各种光学设备的有用元素。嵌段共聚物（BCP）的自组装可以提供通用的解决方案来制造精确的纳米结构，但是这种方法具有固有的局限性，无法实现窄粒子间距离的光学耦合金属多聚体几何形状。这是因为基于BCP的纳米模板因其热力学限制而具有最小的粒子间距离尺寸限制。在本文中，我们研究了通过自组装BCP纳米图案的崩解，容易形成具有可扩展性和区域选择性的金属多聚体。毛细作用力引起的塌陷现象使金属纳米颗粒阵列中横向规则有序的空间转换成为可能，并增强了电场强度。由BCP光刻技术制造的这种金属纳米粒子集合体已成功用于表面增强拉曼散射（SERS）。金属纳米粒子多聚体的增强因子经计算为〜6.74×10在1000 cm ^-1处为⁵，在1022 cm ^-1处为2.04×10 ⁶，在1580 cm ^-1处为6.11×10 ⁶。