Please use this identifier to cite or link to this item:
Title: Role of water in suppressing pecombination pathways in CH3NH3PbI3 perovskite solar cells
Authors: Solanki, Ankur
Lim, Swee Sien
Mhaisalkar, Subodh
Sum, Tze Chien
Keywords: Science::Physics
Issue Date: 2019
Source: Solanki, A., Lim, S. S., Mhaisalkar, S., & Sum, T. C. (2019). Role of water in suppressing pecombination pathways in CH3NH3PbI3 perovskite solar cells. ACS Applied Materials and Interfaces, 11(28), 25474-25482. doi:10.1021/acsami.9b00793
Project: NTU Start-up Grant M4080514 
US Office of Naval Research (ONRGNICOP-N62909-17-1-2155 
Journal: ACS Applied Materials and Interfaces 
Abstract: Moisture degradation of halide perovskites is the Achilles heel of perovskite solar cells. A surprising revelation in 2014 about the beneficial effects of controlled humidity in enhancing device efficiencies overthrew established paradigms on perovskite solar cell fabrication. Despite the extensive studies on water additives in perovskite solar cell processing that followed, detailed understanding of the role of water from the photophysical perspective remains lacking; specifically, the interplay between the induced morphological effects and the intrinsic recombination pathways. Through ultrafast optical spectroscopy, we show that both the monomolecular and bimolecular recombination rate constants decrease by approximately 1 order with the addition of an optimal 1% H2O by volume in CH3NH3PbI3 as compared to the reference (without the H2O additive). Correspondingly, the trap density reduces from 4.8 × 1017 cm-3 (reference) to 3.2 × 1017 cm-3 with 1% H2O. We obtained an efficiency of 12.3% for the champion inverted CH3NH3PbI3 perovskite solar cell (1% H2O additive) as compared to the 10% efficiency for the reference cell. Increasing the H2O content further is deleterious for the device. Trace amounts of H2O afford the benefits of surface trap passivation and suppression of trap-mediated recombination, whereas higher concentrations result in a preferential dissolution of methylammonium iodide during fabrication that increases the trap density (MA vacancies). Importantly, our study reveals the effects of trace H2O additives on the photophysical properties of CH3NH3PbI3 films.
ISSN: 1944-8244
DOI: 10.1021/acsami.9b00793
DOI (Related Dataset):
Schools: School of Materials Science & Engineering 
School of Physical and Mathematical Sciences 
Interdisciplinary Graduate School (IGS) 
Research Centres: Energy Research Institute @ NTU (ERI@N) 
Research Techno Plaza 
Rights: This document is the Accepted Manuscript version of a Published Work that appeared in final form in ACS Applied Materials and Interfaces, copyright © American Chemical Society after peer review and technical editing by the publisher. To access the final edited and published work see
Fulltext Permission: open
Fulltext Availability: With Fulltext
Appears in Collections:SPMS Journal Articles

Citations 10

Updated on Sep 22, 2023

Web of ScienceTM
Citations 10

Updated on Sep 23, 2023

Page view(s)

Updated on Sep 29, 2023

Download(s) 50

Updated on Sep 29, 2023

Google ScholarTM




Items in DR-NTU are protected by copyright, with all rights reserved, unless otherwise indicated.