TY - JOUR
T1 - Evaluation of the Sensitivity Limits of Water Vapor Transmission Rate Measurements Using Electrical Calcium Test
AU - Kempe, Michael D.
AU - Reese, Matthew O.
AU - Dameron, Arrelaine A.
PY - 2013/2
Y1 - 2013/2
N2 - The development of flexible organic light emitting diode displays and flexible thin film photovoltaic devices is dependent on the use of flexible, low-cost, optically transparent and durable barriers to moisture and/or oxygen. It is estimated that this will require high barriers with water vapor transmission rates (WVTR) between 10-4 and 10-6 g/m 2/day. Thus, there is a need to develop a relatively fast, low cost, and quantitative method to evaluate such low permeation rates. Prior works have demonstrated that Ca films, because they change optically and electrically upon reaction with moisture, can be used as a sensor, enabling one to calculate a WVTR between 10 and 10-6 g/m2/day or better. In this work, we analyze the accuracy of an electrical Ca test method. We focus on the effects of the addition of a diffusion spacer and the effects of interactions of edge-seal material with changes to the spacer contacting surface on the overall accuracy. Furthermore, we examine a series of factors that can lead to different errors resulting in qualitative rather than quantitative Ca test behavior. We demonstrate that accurate, relatively high throughput, and reproducible measurements are possible for very low WVTR films in the 10 -6 g/m2/day range.
AB - The development of flexible organic light emitting diode displays and flexible thin film photovoltaic devices is dependent on the use of flexible, low-cost, optically transparent and durable barriers to moisture and/or oxygen. It is estimated that this will require high barriers with water vapor transmission rates (WVTR) between 10-4 and 10-6 g/m 2/day. Thus, there is a need to develop a relatively fast, low cost, and quantitative method to evaluate such low permeation rates. Prior works have demonstrated that Ca films, because they change optically and electrically upon reaction with moisture, can be used as a sensor, enabling one to calculate a WVTR between 10 and 10-6 g/m2/day or better. In this work, we analyze the accuracy of an electrical Ca test method. We focus on the effects of the addition of a diffusion spacer and the effects of interactions of edge-seal material with changes to the spacer contacting surface on the overall accuracy. Furthermore, we examine a series of factors that can lead to different errors resulting in qualitative rather than quantitative Ca test behavior. We demonstrate that accurate, relatively high throughput, and reproducible measurements are possible for very low WVTR films in the 10 -6 g/m2/day range.
UR - http://www.scopus.com/inward/record.url?scp=84874824773&partnerID=8YFLogxK
U2 - 10.1063/1.4789803
DO - 10.1063/1.4789803
M3 - Article
AN - SCOPUS:84874824773
SN - 0034-6748
VL - 84
JO - Review of Scientific Instruments
JF - Review of Scientific Instruments
IS - 2
M1 - 025109
ER -