Higher Open-Circuit Voltage and Stability in MAPbI3 Perovskite Solar Cells Using A Bilayer Hole-Transport Layer with a D-A-D Architectured Polymer

Srivastava, P and Mukherjee, R and Viswanathan, VN and Ramamurthy, PC and Avasthi, S (2018) Higher Open-Circuit Voltage and Stability in MAPbI3 Perovskite Solar Cells Using A Bilayer Hole-Transport Layer with a D-A-D Architectured Polymer. In: 7th IEEE World Conference on Photovoltaic Energy Conversion, WCPEC 2018, 10 - 15 June 2018, Waikoloa Village, pp. 1143-1146.

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Abstract

The open-circuit voltage (VOC) in methylammonium lead iodide (CH3NH3PbI3) perovskite devices should depend on the band-alignment at the hole-transport-layer (HTL)/perovskite interface. However, in practical devices this is not observed. Irrespective of HTL, typical perovskite device show Voc of 1.05-1.07 V. Here we report two polymers that combined with spiro-OMeTAD, shows VOC that is 60 mV higher than comparable spiro-only devices. The highest occupied molecular orbital (HOMO) of these polymers is -5.6 eV, almost perfectly matched with the valence band edge of perovskite, leading to more efficient hole-extraction. The lowest unoccupied molecular orbital (LUMO) of the polymers is low, -3.75-3.9 eV, which is not ideal for blocking electron recombination. However, this negative can be overcome by using a bilayer HTL, with both polymer and spiro-OMeTAD. Perovskite solar cells with polymer/spiro bilayer HTL show a power conversion efficiency (PCE) of 13.91 and VOC of 1.09 V. In addition, the polymer HTL is hydrophobic, which leads to more stable solar cells whose PCE drops from 13.9 to 10.7 after 240 hours of exposure in ambient.

Item Type:	Conference Paper
Publication:	2018 IEEE 7th World Conference on Photovoltaic Energy Conversion, WCPEC 2018 - A Joint Conference of 45th IEEE PVSC, 28th PVSEC and 34th EU PVSEC
Publisher:	Institute of Electrical and Electronics Engineers Inc.
Additional Information:	The copyright for this article belongs to Institute of Electrical and Electronics Engineers Inc.
Keywords:	Energy conversion; Hole mobility; Iodine compounds; Layered semiconductors; Lead compounds; Molecular orbitals; Open circuit voltage; Perovskite; Photoelectrochemical cells; Photovoltaic cells; Polymer solar cells; Polymers; Solar cells; Solar energy; Solar power generation; Timing circuits, Blocking electrons; Highest occupied molecular orbital; Hole extractions; Hole transport layers; Lowest unoccupied molecular orbital; Perfectly matched; Power conversion efficiencies; Valence band edges, Perovskite solar cells
Department/Centre:	Division of Interdisciplinary Sciences > Centre for Nano Science and Engineering
Date Deposited:	04 Aug 2022 11:15
Last Modified:	04 Aug 2022 11:15
URI:	https://eprints.iisc.ac.in/id/eprint/75145

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