AgBiS₂ Nanocrystals: An Emerging Chalcogenide Absorber for Solution Processed Ultra-Thin Film Solar Cells

In this talk I will discuss recent progress in our group on the development of a new class of thin film solar cells employing Silver Bismuth Sulfide as an emerging absorber for solution processed eco-friendly solar cells. I will first introduce our first report on AgBiS2 colloidal nanocrystal solar cells reporting power conversion efficiency of ~6% [1]. Then I will discuss on the opportunities of tuning the optical properties of this ternary compound via controlling cation disorder homogenization. We demonstrated that by homogenizing cation disorder in this compound we can drastically increase the absorption coefficient of this material as one with the high absorption amongst the semiconductors considered for photovoltaics. This taken together with advances on the device architecture led us to reach power conversion efficiencies of ~9% albeit using an absorber of only 35 nm [2]. In the last part of my talk I will describe our initial efforts on developing AgBiS₂ nanocrystal inks and their use with environmentally friendly solvents that led us to achieve efficiencies in excess of 7% [3]. I will conclude my talk with our most recent findings towards an improved passivation strategy of AgBiS₂ nanocrystal inks along with the formation of a double heterojunction in the device stack that led to power conversion efficiencies in excess of 10% with Voc of 0.5V, FF of 0.75 and Jsc of 28 mA/cm².<br/>References:<br/>[1] Solution-processed solar cells based on environmentally friendly AgBiS₂ nanocrystals, M Bernechea, N Cates, G Xercavins, D So, A Stavrinadis, G Konstantatos, Nature Photonics 10 (8), 521-525, 2016<br/><br/>[2] Cation disorder engineering yields AgBiS₂ nanocrystals with enhanced optical absorption for efficient ultrathin solar cells, Y Wang, SR Kavanagh, I Burgués-Ceballos, A Walsh, DO Scanlon, G Konstantatos, Nature Photonics 16 (3), 235-241, 2022<br/><br/>[3] Environmentally Friendly AgBiS₂ Nanocrystal Inks for Efficient Solar Cells Employing Green Solvent Processing Y Wang, L Peng, Z Wang, G Konstantatos, Advanced Energy Materials 12 (21), 2200700, 2022