Engineering the Optoelectronic Properties of Colloidal Alloyed Copper Chalcogenide Quantum Dots for High‐Efficiency Solar Energy Conversion. Issue 10 (11th July 2019)

• Record Type: Journal Article
• Authors: Tong, Xin; Li, Xin; Channa, Ali Imran; Liu, Ruitong; Xu, Jing-Yin; Yu, Peng; Chang, Le; Ji, Haining; Wang, Qiang; Wang, Zhiming M.
• Is Part Of: Solar RRL. Volume 3:Issue 10(2019)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2019-07-11
• Subjects: core/shell structure -- optoelectronic engineering -- photoelectrochemical devices -- quantum dots -- ultralong lifetime; Solar energy -- Periodicals; Photovoltaic power generation -- Periodicals; Solar energy -- Research -- Periodicals; Photovoltaic power generation -- Research -- Periodicals; Periodicals; 333.7923
• DOI: 10.1002/solr.201900186
• Languages: English
• ISSNs: 2367-198X

Abstract

Abstract : Colloidal alloyed copper chalcogenide Cu2 − x Se1 − y S y (CuSeS) quantum dots (QDs) are promising building blocks for solar energy applications because of their unique size/composition‐tunable optical bandgap, which is well matched to the sunlight spectrum. Nevertheless, poor charge separation/transfer and low photostability induced by their intrinsically abundant surface defects/traps tremendously hinder the realization of high‐performance solar energy conversion systems such as solar‐driven photoelectrochemical (PEC) devices. Herein, the synthesis of copper chalcogenide CuSeS core QDs with effective CdS shell passivation is presented. These core/shell QDs exhibit optimized optoelectronic properties with a particularly ultralong lifetime, indicating the formation of type‐II band structure for efficient spatial charge separation, which is further probed using ultrafast transient absorption (TA) spectroscopy. To demonstrate the feasibility of solar energy conversion, solar‐driven PEC cells using such core/shell QDs as light‐converters are fabricated, yielding an impressive saturated photocurrent density of ≈4 mA cm −2 with preeminent durability under 1 sun illumination. This finding highlights a potential technique to engineer the optoelectronic properties of colloidal alloyed copper chalcogenide nanomaterials for high efficiency and stable solar energy conversion devices. Abstract : Colloidal copper chalcogenide CuSeS/CdS core/shell quantum dots (QDs) with engineered optoelectronic properties and type‐II band structure are developed, showing strong visible absorption, near‐infrared emission (≈915 nm), and ultralong lifetime (≈9.5 μs). These core/shell QDs are used to fabricate solar‐driven photoelectrochemical cell, exhibiting a saturated photocurrent density of ≈4 mA cm −2 with preeminent durability.