Key issues in highly efficient perovskite solar cells

Abstract

Preparation of Perovskite solar cell, an emerging low-cost photovoltaic technology in rapid development, has provided a ray of hope to solve the energy problem. However, its low reproducibility and stability limit the wide application of this potential technology. In this review, we summarize the recent progress with a focused discussion on some key issues in the development of perovskite solar cells. Starting from the analysis of basic structure and working principles, we first discuss the perovskite-based light harvesting layer and the general strategy to control its spectrum response. We also demonstrate the effect of film morphology on the device performance and the reproducibility which requires very uniform thin films. Then we discuss the major function of electron transporting layer and hole blocking layer, and point out the importance of compact hole blocking layer with less nano-scaled pinholes. For the hole transporting layer, we focus the discussion on the stability problem induced by widely used dopants that can improve the hole conductivity in the hole transporting layer while the dopants' deliquescent behavior also can induce the decomposition of perovskite-based light harvesting layer with a rapid degradation of the whole device. The potential approaches to solve this stability problem, such as using a dopant-free hole transporting material or making device without any hole transporting materials, are also discussed. Finally, we are in prospect of overcoming the main challenges in the future research for high performance perovskite solar cells.