CdTe Quantum Dot-Pt Cluster Aerogels with Interparticle Schottky Junctions for Improved Charge Carrier Separation.

Because of the built-in electric field established at the interface of semiconductors, the construction of heterojunctions represents an efficient strategy to improve charge carrier separation and enhance the photoelectrochemical (PEC) performance. However, the thickness of the space charge layer induced by the built-in electric field is inherently limited, resulting in inadequate separation of the inner photoinduced carriers within the semiconductors due to a lack of driving force. To effectively utilize the built-in electric field, we synthesized CdTe quantum dot-Pt cluster aerogels. The resulting aerogels, featuring interparticle Schottky junctions, endow the semiconductor with a sufficient driving force for charge separation, where the carrier migration distance to the interface is significantly reduced compared to that of traditional bulk semiconductor-based heterojunctions. This unique configuration amplifies the PEC response by ∼60-fold. The interfacial charge-transfer lifetime increased from 40 to 2400 ps. The flexible self-assembly strategy for the construction of aerogels involving semiconductors and metal clusters offers a fresh perspective on enhancing the charge separation within heterojunctions.