NDLI: Highly reproducible vapor deposition technique, device physics and structural instability of perovskite solar cells

Content Provider	IEEE Xplore Digital Library
Author	Kottokkaran, R. Abbas, H. Balaji, G. Liang Zhang Samiee, M. Kitahara, A. Noack, M. Dalal, V.
Copyright Year	2015
Description	Author affiliation: Iowa State Univ., Ames, IA, USA (Kottokkaran, R.; Abbas, H.; Balaji, G.; Liang Zhang; Samiee, M.; Kitahara, A.; Noack, M.; Dalal, V.)
Abstract	We describe a liquid-free, sequential vapor deposition process for Pb iodide based n-i-p perovskite solar cells, using both methyl-ammonium iodide (MAI) and formamidine iodide (FAI) as the organic molecule. The process consists of sequential deposition of both PbI2 and then vaporization in a vapor of MAI or FAI. The process produces highly reproducible high efficiency devices with efficiencies of ~13.6% for MAI devices and 11.2% for FAI devices. We also study the mid-gap defect densities using capacitance-frequency-temperature techniques. We find two distinct defects, one at 0.24 eV below the conduction band, and one at 0.64 eV below the conduction band. The attempt to escape frequency is also calculated for the midgap defect and it is in the range of 1012 /s. We also study the diffusion length of carriers in the devices by using Quantum Efficiency (QE) vs. voltage techniques for different thicknesses of the perovksite, and we find that for thicker devices, there is a definite loss in QE with increasing forward bias, implying a loss in collection due to shrinking depletion width. From such measurements, we conclude that the field-free diffusion length IS <;0.3 micrometer, and that in thin devices (~0.3 micrometer thickness), the transport is mainly controlled by field assisted drift and not by diffusion. We also study the thermally induced phase change using x-ray diffraction, and decomposition of perovskite devices using thermal gravimetric analysis, and find that at very modest temperatures (~100°C), the MAI devices change their phase with the perovskite degenerating into PbI2 over a period of 24 hours. The devices produced using FAI are more stable, with the phase change not occurring until ~125°C.
Starting Page	1
Ending Page	4
File Size	1377692
Page Count	4
File Format	PDF
e-ISBN	9781479979448
DOI	10.1109/PVSC.2015.7355612
Language	English
Publisher	Institute of Electrical and Electronics Engineers, Inc. (IEEE)
Publisher Date	2015-06-14
Publisher Place	USA
Access Restriction	Subscribed
Rights Holder	Institute of Electrical and Electronics Engineers, Inc. (IEEE)
Subject Keyword	Photovoltaic cells Annealing Voltage measurement Heating Loss measurement Capacitance Liquids field-assisted diffusion perovskite solar cells vapor deposition defect density activation energy of traps diffusion length
Content Type	Text
Resource Type	Article

Sl.	Authority	Responsibilities	Communication Details
1	Ministry of Education (GoI), Department of Higher Education	Sanctioning Authority	https://www.education.gov.in/ict-initiatives
2	Indian Institute of Technology Kharagpur	Host Institute of the Project: The host institute of the project is responsible for providing infrastructure support and hosting the project	https://www.iitkgp.ac.in
3	National Digital Library of India Office, Indian Institute of Technology Kharagpur	The administrative and infrastructural headquarters of the project	Dr. B. Sutradhar bsutra@ndl.gov.in
4	Project PI / Joint PI	Principal Investigator and Joint Principal Investigators of the project	Dr. B. Sutradhar bsutra@ndl.gov.in Prof. Saswat Chakrabarti will be added soon
5	Website/Portal (Helpdesk)	Queries regarding NDLI and its services	support@ndl.gov.in
6	Contents and Copyright Issues	Queries related to content curation and copyright issues	content@ndl.gov.in
7	National Digital Library of India Club (NDLI Club)	Queries related to NDLI Club formation, support, user awareness program, seminar/symposium, collaboration, social media, promotion, and outreach	clubsupport@ndl.gov.in
8	Digital Preservation Centre (DPC)	Assistance with digitizing and archiving copyright-free printed books	dpc@ndl.gov.in
9	IDR Setup or Support	Queries related to establishment and support of Institutional Digital Repository (IDR) and IDR workshops	idr@ndl.gov.in