Tong Xin, Kong Xiang-Tian, Wang Chao, Zhou Yufeng, Navarro-Pardo Fabiola, Barba David, Ma Dongling, Sun Shuhui, Govorov Alexander O, Zhao Haiguang, Wang Zhiming M, Rosei Federico
Institute of Fundamental and Frontier Sciences University of Electronic Science and Technology of China Chengdu 610054 P. R. China.
Institut National de la Recherche Scientifique Centre Énergie Matériaux et Télécommunications 1650 Boul. Lionel Boulet Varennes QC J3X 1S2 Canada.
Adv Sci (Weinh). 2018 Jul 3;5(8):1800656. doi: 10.1002/advs.201800656. eCollection 2018 Aug.
Colloidal heterostructured quantum dots (QDs) are promising candidates for next-generation optoelectronic devices. In particular, "giant" core/shell QDs (g-QDs) can be engineered to exhibit outstanding optical properties and high chemical/photostability for the fabrication of high-performance optoelectronic devices. Here, the synthesis of heterostructured CuInSe S (CISeS)/CdSeS/CdS g-QDs with pyramidal shape by using a facile two-step method is reported. The CdSeS/CdS shell is demonstrated to have a pure zinc blend phase other than typical wurtzite phase. The as-obtained heterostructured g-QDs exhibit near-infrared photoluminescence (PL) emission (≈830 nm) and very long PL lifetime (in the microsecond range). The pyramidal g-QDs exhibit a quasi-type II band structure with spatial separation of electron-hole wave function, suggesting an efficient exciton extraction and transport, which is consistent with theoretical calculations. These heterostructured g-QDs are used as light harvesters to fabricate a photoelectrochemical cell, exhibiting a saturated photocurrent density as high as ≈5.5 mA cm and good stability under 1 sun illumination (AM 1.5 G, 100 mW cm). These results are an important step toward using heterostructured pyramidal g-QDs for prospective applications in solar technologies.
胶体异质结构量子点（QDs）是下一代光电器件的有前途的候选材料。特别是，“巨型”核壳量子点（g-QDs）可以被设计成具有出色的光学性能和高化学/光稳定性，用于制造高性能光电器件。在此，报道了一种通过简便的两步法合成具有金字塔形状的异质结构CuInSe S（CISeS）/CdSeS/CdS g-QDs。结果表明，CdSeS/CdS壳层具有除典型纤锌矿相之外的纯闪锌矿相。所获得的异质结构g-QDs表现出近红外光光光发光（PL）发射（≈830 nm）和非常长的PL寿命（在微秒范围内）。金字塔形g-QDs表现出具有电子-空穴波函数空间分离的准II型能带结构，表明激子的有效提取和传输，这与理论计算结果一致。这些异质结构g-QDs被用作光捕获剂来制造光电化学电池，在1个太阳光照（AM 1.5 G，100 mW cm）下表现出高达≈5.5 mA cm的饱和光电流密度和良好的稳定性。这些结果是朝着将异质结构金字塔形g-QDs用于太阳能技术的潜在应用迈出的重要一步。
