Planar PbS quantum dot/C60 heterojunction photovoltaic devices with 5.2% power conversion efficiency

Of interest for both photovoltaic and photodetector applications is the ability of colloidal quantum dot (CQD) devices to provide response further into the infrared than is typical for other solution-processable materials. Here, we present a simple heterojunction diode structure that utilizes the extended infrared absorption of PbS CQDs. We show that device performance benefits from a discontinuous exciton blocking layer which improves charge separation without limiting charge extraction. By enhancing charge carrier mobility in the CQD layer, we demonstrate a planar heterostructure device with a power conversion efficiency of 5.2% under 1 sun illumination. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4707377]