KEYWORDS: Copper indium gallium selenide, Manufacturing, Thin films, Solar cells, Photovoltaics, Silicon, Solar energy, Thin film solar cells, Glasses, Crystals
In recent years, thin-film photovoltaic (PV) companies started realizing their low manufacturing cost potential, and
grabbing an increasingly larger market share from multicrystalline silicon companies. Copper Indium Gallium Selenide
(CIGS) is the most promising thin-film PV material, having demonstrated the highest energy conversion efficiency in
both cells and modules. However, most CIGS manufacturers still face the challenge of delivering a reliable and rapid
manufacturing process that can scale effectively and deliver on the promise of this material system. HelioVolt has
developed a reactive transfer process for CIGS absorber formation that has the benefits of good compositional control,
high-quality CIGS grains, and a fast reaction. The reactive transfer process is a two stage CIGS fabrication method.
Precursor films are deposited onto substrates and reusable print plates in the first stage, while in the second stage, the
CIGS layer is formed by rapid heating with Se confinement. High quality CIGS films with large grains were produced
on a full-scale manufacturing line, and resulted in high-efficiency large-form-factor modules. With 14% cell efficiency
and 12% module efficiency, HelioVolt started to commercialize the process on its first production line with 20 MW
nameplate capacity.
KEYWORDS: Copper indium gallium selenide, Thin films, Photovoltaics, Manufacturing, Solar cells, Silicon, Printing, Thin film solar cells, Crystals, Solar energy
We demonstrate photovoltaic integrated circuits (PVIC) with high-quality large-grain Copper Indium Gallium
Selenide (CIGS) obtained with the unique combination of low-cost ink-based or Physical Vapor Deposition (PVD)
based nanoengineered precursor thin films and a reactive transfer printing method. Reactive transfer is a two-stage
process relying on chemical reaction between two separate precursor films to form CIGS, one deposited on the
substrate and the other on a printing plate in the first stage. In the second stage, these precursors are brought into
intimate contact and rapidly reacted under pressure in the presence of an electrostatic field while heat is applied.
The use of two independent thin films provides the benefits of independent composition and flexible deposition
technique optimization, and eliminates pre-reaction prior to the synthesis of CIGS. High quality CIGS with large
grains on the order of several microns, and of preferred crystallographic orientation, are formed in just several
minutes based on compositional and structural analysis by XRF, SIMS, SEM and XRD. Cell efficiencies of 14%
and module efficiencies of 12% have been achieved using this method. When atmospheric pressure deposition of
inks is utilized for the precursor films, the approach additionally provides further reduced capital equipment cost,
lower thermal budget, and higher throughput.
Low cost manufacturing of Cu(In,Ga)Se2 (CIGS) films for high efficiency photovoltaic devices by the innovative
Field-Assisted Simultaneous Synthesis and Transfer (FASST®) process is reported. The FASST® process is a two-stage
reactive transfer printing method relying on chemical reaction between two separate precursor films to form CIGS, one
deposited on the substrate and the other on a printing plate in the first stage. In the second stage these precursors are brought
into intimate contact and rapidly reacted under pressure in the presence of an applied electrostatic field. The method
utilizes physical mechanisms characteristic of anodic wafer bonding and rapid thermal annealing, effectively creating a
sealed micro-reactor that ensures high material utilization efficiency, direct control of reaction pressure, and low thermal
budget. The use of two independent ink-based or PVD-based nanoengineered precursor thin films provides the benefits of
independent composition and flexible deposition technique optimization, and eliminates pre-reaction prior to the second
stage FASST® synthesis of CIGS. High quality CIGS with large grains on the order of several microns are formed in just
several minutes based on compositional and structural analysis by XRF, SIMS, SEM and XRD. Cell efficiencies of 12.2%
have been achieved using this method.
Conference Committee Involvement (2)
Thin Film Solar Technology II
1 August 2010 | San Diego, California, United States
Thin Film Solar Technology
2 August 2009 | San Diego, California, United States
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.