Hautzinger Matthew P, Ge Qiutong, Haque Md Azimul, Whittaker St John, Yazawa Keisuke, Lee Stephanie S, Sercel Peter C, Beard Matthew C
National Renewable Energy Laboratory, Golden, Colorado 80401, United States.
Molecular Design Institute, Department of Chemistry, New York University, NY, New York 10003, United States.
ACS Nano. 2025 May 27;19(20):19141-19148. doi: 10.1021/acsnano.5c00472. Epub 2025 May 15.
Chiral halide perovskites (c-HPs) merge the chirality of organic cations with the semiconducting properties of metal halide frameworks, creating a family of chiral semiconductors with tunable chiroptoelectronic behavior. Here, we describe the impact of periodic banded morphologies of textured c-HP (-NEA)PbBr films (NEA = 1-(1-naphthyl)ethylammonium) on their chiroptical behavior. Due to the interplay between the crystalline and glassy phases, the c-HP film growth is driven by rhythmic precipitation, producing a distinctive controllable radial banded pattern with the (-NEA)PbBr inorganic planes oriented parallel to the substrate. The banded morphology can be controlled, as evidenced by the growth temperature dictating the ridge-to-ridge spacing as well as the density of banded regions. The resulting circular dichroism (CD) spectral shape, intensity, and polarity vary in a seemingly random manner across processing conditions. However, these spectral features can be explained by considering key features of the banded morphology, such as refraction of the incident light due to surface morphology, birefringence, and stacked, rotated crystallites. These effects cannot be canceled by averaging front and back CD spectra of c-HP films, and our model incorporating these effects reproduces all observed CD spectra remarkably well. The control over the c-HP morphology and prediction capabilities of our CD modeling leads to further understanding of this class of semiconductors and the possibility of exploiting structural features for light polarization control akin to enhanced metamaterials.
手性卤化物钙钛矿（c-HPs）将有机阳离子的手性与金属卤化物框架的半导体性质相结合，创造出了一类具有可调节手性光电器件行为的手性半导体。在此，我们描述了织构化的c-HP（-NEA）PbBr薄膜（NEA = 1-（1-萘基）乙铵）的周期性带状形态对其圆二色性（CD）行为的影响。由于晶相和玻璃相之间的相互作用，c-HP薄膜的生长由有节奏的沉淀驱动，产生一种独特的、可控的径向带状图案，其中（-NEA）PbBr无机平面与衬底平行排列。带状形态是可以控制的，生长温度决定了脊与脊之间的间距以及带状区域的密度就证明了这一点。在不同的加工条件下，所得的圆二色性（CD）光谱形状、强度和极性以一种看似随机的方式变化。然而，这些光谱特征可以通过考虑带状形态的关键特征来解释，比如由于表面形态导致的入射光折射、双折射以及堆叠、旋转的微晶。c-HP薄膜前后的CD光谱平均并不能消除这些影响，并且我们包含这些影响的模型能够非常好地再现所有观察到的CD光谱。对c-HP形态的控制以及我们CD建模的预测能力有助于进一步理解这类半导体，并且有可能利用其结构特征来控制光的偏振，类似于增强型超材料。
