AgAuSe Quantum Dots-Based Eco-Friendly Solar Cells

Colloidal quantum dots (QDs) without toxic heavy metals are promising candidates for exploiting the next-generation solar cells by virtue of their numerous merits, including solution processability, facile bandgap tunability and wide absorption spectrum range. However, a large number of photo-generated carriers are captured by their inherent defects instead of effective dissociation, which immensely hinders the device performance. Herein, the silver-gold-selenide (AgAuSe) QDs with well-treated defect states were firstly employed as the photo-absorber of active layer to construct environment-friendly QD solar cells, in which an inverted AgAuSe QD solar cell composed of ITO/SnO2/AgAuSe/Au/PCE10:BTP-4Cl/MoO3/Al was fabricated. Thereinto, after the n-i-p infrastructure of SnO2/QD/PCE10 being determined, a layer of Au nanoparticles (NPs) was introduced into the QD/PCE10 interface to modulate the energy-level alignment of the device. This interfacial modification significantly improved the device performance by increasing the open-circuit voltage and fill factor, which was different from the absorption enhancement mechanism originated from the plasmonic effects of Au NPs. Lastly, the PCE10 layer was blended with BTP-4Cl to increase the short-circuit current density of device through its complementary absorption to AgAuSe QD, which further increased the power conversion efficiency up to 4.14% with the synergistic effect of Au NPs layer.