Low-Cost RoHS Compliant Solution Processed Photovoltaics Enabled by Ambient Condition Synthesis of AgBiS2 Nanocrystals

Abstract

Two major challenges exist before colloidal nanocrystal solar cells can take their place in the market: So far, these devices are based on Pb/Cd-containing nanocrystals, and second, the synthesis of these nanocrystals takes place in an inert atmosphere at elevated temperatures due to the use of air-sensitive chemicals. In this report, a room-temperature, ambient-air synthesis for nontoxic AgBiS2 nanocrystals is presented. As this method utilizes stable precursors, the need for the use of a protective environment is eliminated, enabling the large-scale production of AgBiS2 nanocrystals. The production cost of AgBiS2 NCs at room temperature and under ambient conditions reduces by ∼60% compared to prior reports based on hot injection, and the solar cells made of these nanocrystals yield a promising power conversion efficiency (PCE) of 5.5%, the highest reported to date for a colloidal nanocrystal material free of Pb or Cd synthesized at room temperature and under ambient conditions.