Enhancement of hole extraction efficiency of dibenzothiophenes by substitution engineering: Toward additive-free perovskite solar cells with power conversion efficiency exceeding 20%
Document Type
Article
Publication Date
7-1-2022
Abstract
Replacement of hole-transporting materials (HTM) for additive-free perovskite solar cells (PSCs) is an urgent issue. In this work, three new derivatives of dibenzothiophene with methoxyphenyl, trimethoxyphenyl, carbazole moieties are synthesized as hole-transporting materials for PSCs. The hole density dynamics and hole transporting properties of synthesized dibenzothiophene derivatives are investigated by combination of the charge extraction by linearly increasing voltage (CELIV) and time-of-flight (TOF) techniques. The TOF hole mobility (mu(h)) of one compound reaches the highest value of 4.2 x 10(-3) cm(2) V(-1)s(-1) at an electric field of 2.5 x 10(5) V cm(-1), however additive-free layers in PSCs did not show the best performance. Instead, the PSC efficiency is determined by a trade-off between the hole-mobility properties and the ``effective'' hole recombination rate k(B) ranging 0.5-40.3 ms(-1) as determined by means of the CELIV method. The best hole extraction properties are observed for a compound with mu(h) of 9.45 x 10(-4) cm(2) V(-1)s(-1) and k(B) of 11.8 ms(-1) which is coherent with its lowest energetic disorder sigma of 78.2 meV. Having both appropriate hole density dynamics and hole-transporting properties, hole-transporting layer of that compound allows to reach PCE of 20.9% for additive-free PSC, which is among the state-of-art values for devices with undoped HTM.
Keywords
Additive-free hole-transporting materials, Energetic disorder parameters, Hole mobility, Hole recombination dynamics, Perovskite solar cells
Divisions
PHYSICS
Funders
Research Council of Lithuania (LMTLT) [Grant No: S-MIP-20-42],Swedish Foundation for Strategic Research [Grant No: RMA15-0130],University Malaya Impact Orientated Interdisciplinary Research Grant [Grant No: IIRG005A-19FNW],Swedish Foundation for Strategic Research [Grant No: RMA15-0130]
Publication Title
Solar RRL
Volume
6
Issue
7
Publisher
Wiley-V C H Verlag GMBH
Publisher Location
POSTFACH 101161, 69451 WEINHEIM, GERMANY