Pyridine-Terminated Conjugated Organic Molecules as an Interfacial Hole Transfer Bridge for NiOx-Based Perovskite Solar Cells

Haoliang Cheng; Yaru Li; Guanyu Zhao; Ke Zhao; Zhong-Sheng Wang

doi:10.1021/acsami.9b09530

Pyridine-Terminated Conjugated Organic Molecules as an Interfacial Hole Transfer Bridge for NiO_x-Based Perovskite Solar Cells

ACS Appl Mater Interfaces. 2019 Aug 14;11(32):28960-28967. doi: 10.1021/acsami.9b09530. Epub 2019 Jul 31.

Authors

Haoliang Cheng¹, Yaru Li¹, Guanyu Zhao¹, Ke Zhao¹, Zhong-Sheng Wang¹

Affiliation

¹ Department of Chemistry, Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials, Laboratory of Advanced Materials, iChEM (Collaborative Innovation Center of Chemistry for Energy Materials) , Fudan University , 2205 Songhu Road , Shanghai 200438 , China.

PMID: 31318205
DOI: 10.1021/acsami.9b09530

Abstract

To engineer the NiO_x/perovskite interface and promote interfacial hole transfer, two pyridine-terminated conjugated small organic molecules (PTZ-1 and PTZ-2) are synthesized to link the NiO_x and perovskite layers for NiO_x-based perovskite solar cells (PSCs). One terminal pyridine group interacts with the NiO_x layer, while the other one coordinates with the Pb atoms of the perovskite layer, erecting an interfacial hole transfer bridge between NiO_x and perovskite. Surface modification of the NiO_x film with the PTZ molecules is able to enhance hole extraction, increase hole mobility and conductivity of NiO_x, reduce defect density, and retard interfacial charge recombination. As a consequence, power conversion efficiency is improved from 12.53 to 16.25 and 17.00% upon surface modifications of NiO_x with PTZ-1 and PTZ-2, respectively. Furthermore, the modified PSCs exhibit almost no hysteresis and show good stability after storage in air (relative humidity of 30-40%) for 500 h without encapsulation.

Keywords: conjugated organic molecules; hole transfer bridge; passivation of defects; pyridine; tuning of energy levels.