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Enhanced Hetero‐Junction Quality and Performance of Kesterite Solar Cells by Aluminum Hydroxide Nanolayers and Efficiency Limitation Revealed by Atomic‐resolution Scanning Transmission Electron Microscopy
Author(s) -
Xie Haibing,
Sánchez Yudania,
Tang Pengyi,
EspíndolaRodríguez Moisés,
Guc Maxim,
CalvoBarrio Lorenzo,
LópezMarino Simon,
Liu Yu,
Morante Joan R.,
Cabot Andreu,
IzquierdoRoca Victor,
Arbiol Jordi,
PérezRodríguez Alejandro,
Saucedo Edgardo
Publication year - 2019
Publication title -
solar rrl
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.544
H-Index - 37
ISSN - 2367-198X
DOI - 10.1002/solr.201800279
Subject(s) - kesterite , materials science , passivation , scanning transmission electron microscopy , photoluminescence , open circuit voltage , high resolution transmission electron microscopy , x ray photoelectron spectroscopy , saturation current , optoelectronics , transmission electron microscopy , nanotechnology , chemical engineering , solar cell , voltage , czts , physics , layer (electronics) , quantum mechanics , engineering
A strategy for interface engineering of hetero‐junctions in kesterite solar cells by using Al(OH) 3 is demonstrated. The hydroxide nanolayers are prepared via a facile and fast wet chemical route, based on an aqueous solution of aluminum chlorides and thioacetamide. Considerable enhancement of open circuit voltage ( V oc ) (30–60 mV) and fill factor (FF) (10–20%) after this chemical treatment are observed, achieving a champion conversion efficiency of 9.1% and a champion FF of 70% (among the best FF in kesterite solar cells). The functional mechanism is systematically studied by current‐voltage, capacitance‐voltage, temperature dependence of current–voltage and photoluminescence measurements, which reveal that Al(OH) 3 nanolayers can effectively reduce the interface recombination and largely improve the shunt resistance. Furthermore, atomic resolution high angle annular dark field scanning transmission electron microscopy (HAADF‐STEM) evidences the epitaxial relationship of Al(OH) 3 with kesterite and CdS, indicating the benign and effective interface passivation achieved by this chemical treatment. Finally, based on HAADF‐STEM and electron energy loss spectroscopy mappings, insights into the efficiency limiting and beneficial factors for CZTSSe solar cells, as well as suggestions to further improve both the bulk and related interfaces are presented.