Simple strategies deployed for developing efficient and stable solution processed quantum dot solar cells

Abstract

Inorganic quantum dot (QD) semiconductors offer tailorable bandgaps thus rendering them attractive as photosensitizers for solar cells. The currently evolving strategies employed for developing low-cost quantum dot solar cells (QDSCs) is the focus of this review. Although cost-effective and simple approaches of synthesizing QDs and the subsequent semi-solid-state solar cell fabrication has caught the attention of many research groups, the power conversion efficiencies (PCEs) were initially not as high as expected with what was achieved with molecular dyes. During the period of 2005–2012, the PCEs were less than 5% under one sun illumination. But when the effective utilization of suitable passivation layers, alloyed QDs, and novel catalytic counter electrodes (CEs) came into the picture, the PCE values rapidly increased to greater than 15%. This review thus focuses on highlighting the role of passivation layers applied over QD/sensitized photoanodes, passivation mechanism/methods, and the use of novel CEs that have resulted in high-performance QDSCs.