Alruwaili Amal, Alkhudhari Osama M, Wang Ran, Jia Zhenyu, Saunders Jennifer M, Picheo Eugenio, Toolan Daniel T W, Lyon L Andrew, Saunders Brian R
Department of Materials, University of Manchester, Nancy Rothwell Building, Manchester M1 7HL, UK; Department of Physics, College of Science, Jouf University, P.O. Box 2014, Sakaka 72446, Kingdom of Saudi Arabia.
Department of Materials, University of Manchester, Nancy Rothwell Building, Manchester M1 7HL, UK; Department of Chemistry, College of Science, Taif University, Taif 21944, Kingdom of Saudi Arabia.
J Colloid Interface Sci. 2025 Aug 5;701:138591. doi: 10.1016/j.jcis.2025.138591.
Poly(N-isopropylacryamide) microgels (PNIPAM MGs) are interesting model colloids with remarkable self-ordering properties. Metal halide perovskites (MHPs) are solution processable semiconductors that have attracted great interest for optoelectronics applications. Very few studies have considered complex co-crystallizing systems and their effects on structural order formation. This work examines PNIPAM MG ordering within a MHP matrix and investigates whether these pure PNIPAM MGs could form arrays on the MHP surface, passivate MHP defects and provide structurally colored films and solar cells.
We use a mixed cation MHP (FAMAPbI) (FA and MA are formamidinium and methylammonium) and investigate the effects of MG size and PNIPAM MG/MHP composite composition on two-dimensional non-closed packed hexagonal array (2D-NCPHA) formation and structural color. SEM and angle-dependent observations of illuminated films are used to assess structural order as well as the colors of light generated within composite films and MHP solar cells. The colors observed were converted to CIE1931 values and the color trends predicted by a simple ray-tracing equation.
We show that spontaneous ordering of PNIPAM MGs occurred on the MHP matrix and caused color generation from a relatively thick co-crystallizing MHP matrix. An optimum PNIPAM MG diameter is identified and the mechanisms operative are elucidated. Structurally colored solar cells are also demonstrated and their efficiency improvement is due to PNIPAM passivation of MHP defects. The results of this study indicate that PNIPAM 2D-NCPHA formation is highly tolerant to solution species and would allow, in principle, such phenomena to be achieved in other co-crystallizing matrices.
聚（N-异丙基丙烯酰胺）微凝胶（PNIPAM MGs）是具有显著自排序特性的有趣模型胶体。金属卤化物钙钛矿（MHPs）是可溶液加工的半导体，在光电子应用中引起了极大兴趣。很少有研究考虑复杂的共结晶体系及其对结构有序形成的影响。这项工作研究了MHP基质中PNIPAM MG的有序排列，并研究了这些纯PNIPAM MGs是否能在MHP表面形成阵列、钝化MHP缺陷并提供结构色薄膜和太阳能电池。
我们使用混合阳离子MHP（FAMAPbI）（FA和MA分别是甲脒和甲基铵），并研究MG尺寸和PNIPAM MG/MHP复合材料组成对二维非封闭堆积六边形阵列（2D-NCPHA）形成和结构色的影响。使用扫描电子显微镜（SEM）和对照明薄膜的角度依赖性观察来评估复合薄膜和MHP太阳能电池内的结构有序度以及产生的光的颜色。观察到的颜色被转换为CIE1931值，并通过简单的光线追踪方程预测颜色趋势。
我们表明，PNIPAM MGs在MHP基质上自发排序，并导致相对较厚的共结晶MHP基质产生颜色。确定了最佳的PNIPAM MG直径，并阐明了其作用机制。还展示了结构色太阳能电池，其效率提高归因于PNIPAM对MHP缺陷的钝化。这项研究的结果表明，PNIPAM二维非封闭堆积六边形阵列的形成对溶液种类具有高度耐受性，原则上允许在其他共结晶基质中实现这种现象。
