Buried interface engineering enables efficient and refurbished CsPbI3 perovskite quantum dot solar cells

Abstract

Interfacial engineering has proven to be extremely important for the colloidal quantum dot (QD) solar cells. However, in comparison with QD surface and device top interface, the buried interface has received much less attention. Herein, we report an efficient strategy utilizing cyclic passivator (CyP), namely acesulfame potassium, to modulate the titanium oxide (TiO2)/CsPbI3 QD buried interface. The isotropic CyP can effectively passivate defects at TiO2 and CsPbI3 QD surface through target chemical binding, hence facilitate the interfacial charge extraction and transport. Substantially, the CyP-engineered buried interface output a high power conversion efficiency (PCE) of 17.50% for all-inorganic CsPbI3 perovskite QD solar cells. More importantly, we first reported the refurbishment of high-efficiency QD solar cells, and the CyP buried modulation can assist the recycling of high-cost TiO2/F-doped tin oxide electrode. The PCE of CyP-engineered refurbished CsPbI3 QD device maintains over 90% of corresponding fresh one after up to 4th round recycling of the retired devices. These findings first reveal the importance and potential of buried interface that will propel both performance and sustainable development of QD based optoelectronic devices.