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Thickness dependence of a CuI hole transport layer on initial photostability and photovoltaic performance of organic solar cells
Author(s) -
Yoon Sangcheol,
Kim Hyebin,
Shin EulYong,
Noh YongYoung,
Park Byoungchoo,
Hwang Inchan
Publication year - 2016
Publication title -
physica status solidi (a)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.532
H-Index - 104
eISSN - 1862-6319
pISSN - 1862-6300
DOI - 10.1002/pssa.201600052
Subject(s) - materials science , x ray photoelectron spectroscopy , organic solar cell , indium tin oxide , layer (electronics) , indium , energy conversion efficiency , thin film , optoelectronics , chemical engineering , photovoltaic system , active layer , surface roughness , surface finish , nanotechnology , thin film transistor , composite material , polymer , ecology , engineering , biology
Understanding the effects of interlayers in organic photovoltaic devices is necessary to investigate its potential to maximize efficiencies. Here, we investigate how a solution‐processed copper (I) iodide (CuI) hole transport layer (HTL) prepared onto indium tin oxide (ITO) substrates affects the photovoltaic performances of the devices based on Poly(3‐hexylthiophene‐2,5‐diyl) (P3HT):Phenyl‐C61‐butyric acid methyl ester (PCBM), with its different thicknesses. We found that the film morphology and roughness depends sensitively on the concentration of CuI solutions used for thin films. The surface of CuI films spun with high concentration solutions consists of large grains with high roughness, resulting in a direct short in the devices. For the devices with a thin CuI layer, the power conversion efficiency (PCE) of the devices under illumination was observed to decrease with time. The X‐ray photoelectron spectroscopy (XPS) suggests that the indium ions might be diffused into the active layer across the thin CuI layer. Our results highlight that the CuI layer thickness is a key parameter in affecting not only efficiency but also device yield and short‐term photostability.