Gradient-Band Alignment Homojunction Perovskite Quantum Dot Solar Cells

Jifeng Yuan; Chenghao Bi; Jiahao Xi; Ruiqi Guo; Jianjun Tian

doi:10.1021/acs.jpclett.0c03628

Gradient-Band Alignment Homojunction Perovskite Quantum Dot Solar Cells

J Phys Chem Lett. 2021 Jan 28;12(3):1018-1024. doi: 10.1021/acs.jpclett.0c03628. Epub 2021 Jan 20.

Authors

Jifeng Yuan¹, Chenghao Bi¹, Jiahao Xi¹, Ruiqi Guo¹, Jianjun Tian¹

Affiliation

¹ Institute for Advanced Materials and Technology, University of Science and Technology Beijing, Beijing 100083, China.

PMID: 33470817
DOI: 10.1021/acs.jpclett.0c03628

Abstract

The inorganic perovskite CsPbI₃ that exists in the form of a quantum dot (QD) shows a stable cubic structure, attracting much attention for its application in solar cells. However, too many grain boundaries in the perovskite QD (PQD) layer block the transport of carriers, resulting in the potential loss of solar cells. Herein, we devise a gradient-band alignment (GBA) homojunction, which is constructed from three layers of PQDs with different band-gaps to form a gradient energy alignment. The GBA structure facilitated the charge extraction and increased the carrier diffusion length of the PQD layer because of the additional driving force for the electrons. In addition, the homojunction made from the same substance could minimize the lattice mismatch of the active layer. As a result, the champion solar cell based on the GBA homojunction layer achieved a high open voltage V_OC of 1.25 V and a power conversion efficiency (PCE) of 13.2%.