Solar PV PhD thesis (absorption enhancement in thin films)

Absorption Enhancement in Thin-Film Polycrystalline-Silicon Photovoltaic Modules (1996)
University of New South Wales (Sydney, Australia)
with thanks to the Royal Society, UK, for the Rutherford Scholarship that supported me to do this.
  • Modelling of anti-reflection and light-trapping properties of thin silicon films deposited "conformally" on macro-textured substates (with texture size or "period" > film thickness).
  • Uses ray-tracing of average year-round illumination and includes anti-reflection coatings for the top glass surface as well as the silicon-encapsulation surface (and a rear cell reflector).
  • The anti-reflection and light trapping properties are superior to that calculated for a realistic micro-texture, which is modelled using a new kind of ray-tracing program.
  • A low shading-loss contacting scheme for thin-film silicon solar photovoltaic (PV) modules is also proposed.
  • Conclusions:
    • Conformal films on small-sized inverted tetrahedra (triangular based pyramids with dimensions of around 10-50 microns for a film thickness of 1-3 microns) can produce light trapping that is better than a fully randomising "lambertian" scheme, even under isotropic illumination (which was previously considered to be a theoretical limit).
    • From a practical perspective, the best texture is probably "perpendicular grooves", consisting of conformal silicon films on macro-sized grooves oriented perpendicular to North-South grooves on the top glass/encapsulation surface (running downhill to assist rain cleaning), along with an additional mild micro-texture on the front or rear silicon surface.  This offers lower series resistance for current flowing along the silicon grooves towards contacts, compared to a 3D texture.


Light trapping with conformal thin films on inverted tetrahedra        

Low shading-loss contacting scheme:

PhD in Word
David Thorp,
17 Dec 2015, 19:43
David Thorp,
17 Dec 2015, 19:42
pascal ray tracing
David Thorp,
2 Jan 2016, 20:10