Paper TF+EN-WeM12
Inorganic Functionalization of Colloidal Quantum Dot Solar Cells through ALD Infilling

Wednesday, October 21, 2015, 11:40 am, Room 111

Colloidal quantum dot (CQD) solar cells are of great interest due to the tunable nature of the quantum dot light absorbers through size, composition and interface engineering, together with the potential for low-cost fabrication through solution processing techniques. Lead chalcogenide CQD devices have recently gained traction with rapidly improving efficiencies (>9%). Great strides have been made with organic ligand functionalization of the quantum dot surfaces to enhance CQD transport properties; however, these devices often suffer from poor long-term stability and are still limited by carrier lifetime and mobility. Atomic layer deposition (ALD), a technique that allows for conformal coating of nanostructured surfaces, has been used to improve stability and mobility of CQD solar cells by growing oxides within the quantum dot film. In this work, we explore the inorganic functionalization of CQD solar cells through combinations of ALD materials, including Al₂O₃, ZnO, NiO and other oxide materials, in thin (~30 nm) devices to ensure infilling throughout the entire device. With the proper choice of ALD oxide, short circuit current density and overall efficiency could be enhanced by 70% and 10% respectively relative to the non-infilled control CQD device. We will discuss the effects of ALD inorganic functionalization on surface passivation and carrier mobility as well as methods to implement ALD infilling on thicker devices in order to ultimately push the limits of CQD solar cell performance.