Lead sulfide quantum dots inside ferritin: synthesis and application to photovoltaics

We present a new water phase synthesis method for lead sulfide colloidal quantum dots, and test their applicability for use in photovoltaics. The quantum dots are synthesized inside ferritin protein shells (PbS-FTN). Our synthesis method is simpler than what has previously been reported for PbS-FTN quantum dots, namely we demonstrate that the synthesizing reaction can be run in an aerobic environment and with a Pb:S ratio of 1:1. Protection from photocorrosion is demonstrated by comparing the time evolution of photoluminescence from PbS-FTN with that of non-ferritin PbS quantum dots. In the photovoltaic testing, we use a dye-sensitized solar cell scheme with PbS-FTN as the dye and test several methods to adsorb PbS-FTN to the mesoporous TiO2 layer which is coated on the solar cell anodes. The highest performing cell shows an efficiency of 0.29% using the drop casting method.