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Title: Strong Attraction and Adhesion Forces of Dust Particles by System Voltages of Photovoltaic Modules

Abstract

We report for the first time on direct measurements using atomic force microscopy (AFM) of electric field induced attraction and adhesion forces associated with soiling on photovoltaic (PV) modules. Real dust particles and silica spheres as surrogate to simulating dust particles were glued to AFM probe cantilevers. The electric field induced force (Fes) was measured via AFM force-distance (f-z) curves, where the electric field was generated by applying a voltage (Vs) to a simulated PV module. Fes and van der Waals (Fvw) force contributions could be separated with the f-z curves. The results show that Fes ~2.5 u N on dust particles is ~5 times larger than Fvw ~0.5 u N at even Vs = -100 V (i.e., similar to large-module operating voltages). Fes increases by an order of magnitude as the applied potential increases from Vs = -100 V to Vs = -500 V. These adhesion forces are by far the strongest that we have measured using the AFM technique for 'initial' contact of particles. Furthermore, unlike the more typical short-range forces of Fvw and liquid bridge, Fes extends sub-millimeters to a millimeter beyond the PV module surface, creating large attraction forces to even uncharged dust particles (i.e., viamore » induced dipoles) in the air. These results indicate that the high voltages typically used with PV arrays today will attract more dust particles from the air, hold the dust particles to the surface very strongly, and potentially induce other PV module surface effects, all of which could increase the power production losses because of soiling.« less

Authors:
 [1];  [1];  [1];  [1];  [1];  [1];  [1];  [1]
  1. National Renewable Energy Laboratory (NREL), Golden, CO (United States)
Publication Date:
Research Org.:
National Renewable Energy Lab. (NREL), Golden, CO (United States)
Sponsoring Org.:
USDOE Office of Energy Efficiency and Renewable Energy (EERE), Solar Energy Technologies Office (EE-4S)
OSTI Identifier:
1543123
Report Number(s):
NREL/JA-5K00-70821
DOE Contract Number:  
AC36-08GO28308
Resource Type:
Journal Article
Journal Name:
IEEE Journal of Photovoltaics
Additional Journal Information:
Journal Volume: 9; Journal Issue: 4
Country of Publication:
United States
Language:
English
Subject:
14 SOLAR ENERGY; adhesion force; atomic force microscopy; electric field; electric field attraction; electrostatic; photovoltaic; soiling; system voltage

Citation Formats

Jiang, Chun Sheng, Moutinho, Helio R, To, Bobby, Xiao, Chuanxiao, Perkins, Craig, Muller, Matthew, Al-Jassim, Mowafak M, and Simpson, Lin J. Strong Attraction and Adhesion Forces of Dust Particles by System Voltages of Photovoltaic Modules. United States: N. p., 2019. Web. doi:10.1109/JPHOTOV.2019.2907174.
Jiang, Chun Sheng, Moutinho, Helio R, To, Bobby, Xiao, Chuanxiao, Perkins, Craig, Muller, Matthew, Al-Jassim, Mowafak M, & Simpson, Lin J. Strong Attraction and Adhesion Forces of Dust Particles by System Voltages of Photovoltaic Modules. United States. doi:10.1109/JPHOTOV.2019.2907174.
Jiang, Chun Sheng, Moutinho, Helio R, To, Bobby, Xiao, Chuanxiao, Perkins, Craig, Muller, Matthew, Al-Jassim, Mowafak M, and Simpson, Lin J. Fri . "Strong Attraction and Adhesion Forces of Dust Particles by System Voltages of Photovoltaic Modules". United States. doi:10.1109/JPHOTOV.2019.2907174.
@article{osti_1543123,
title = {Strong Attraction and Adhesion Forces of Dust Particles by System Voltages of Photovoltaic Modules},
author = {Jiang, Chun Sheng and Moutinho, Helio R and To, Bobby and Xiao, Chuanxiao and Perkins, Craig and Muller, Matthew and Al-Jassim, Mowafak M and Simpson, Lin J},
abstractNote = {We report for the first time on direct measurements using atomic force microscopy (AFM) of electric field induced attraction and adhesion forces associated with soiling on photovoltaic (PV) modules. Real dust particles and silica spheres as surrogate to simulating dust particles were glued to AFM probe cantilevers. The electric field induced force (Fes) was measured via AFM force-distance (f-z) curves, where the electric field was generated by applying a voltage (Vs) to a simulated PV module. Fes and van der Waals (Fvw) force contributions could be separated with the f-z curves. The results show that Fes ~2.5 u N on dust particles is ~5 times larger than Fvw ~0.5 u N at even Vs = -100 V (i.e., similar to large-module operating voltages). Fes increases by an order of magnitude as the applied potential increases from Vs = -100 V to Vs = -500 V. These adhesion forces are by far the strongest that we have measured using the AFM technique for 'initial' contact of particles. Furthermore, unlike the more typical short-range forces of Fvw and liquid bridge, Fes extends sub-millimeters to a millimeter beyond the PV module surface, creating large attraction forces to even uncharged dust particles (i.e., via induced dipoles) in the air. These results indicate that the high voltages typically used with PV arrays today will attract more dust particles from the air, hold the dust particles to the surface very strongly, and potentially induce other PV module surface effects, all of which could increase the power production losses because of soiling.},
doi = {10.1109/JPHOTOV.2019.2907174},
journal = {IEEE Journal of Photovoltaics},
number = 4,
volume = 9,
place = {United States},
year = {2019},
month = {5}
}