RENA has launched its ‘monoTEX,’ IPA-free alkaline texturing process for solar cells. has established that this process is key for their breakthrough mono-crystalline cell concept. RENA’s combination of pre-cleaning and monoTEX texturing is claimed to provide a homogeneous surface with a distribution of pyramid sizes that, together with an optimization of the complete process sequence, enables a cell efficiency that is well beyond the 20% mark. RENA claims to be ‘best in class’ with the monoTEX texturing and has already more than 200 million wafers production experience at different customer plants such as California-based TetraSun.

Problem: IPA-based KOH texturing of monocrystalline Si-wafers causes not only environmental and cost problems but also micro- and macro- inhomogeneities with direct influence to the efficiencies of the cells.

Solution: monoTEX is a new type of moderating and wetting agent for IPA-free alkaline texturing. RENA’s combination of pre-cleaning and monoTEX texturing leads to a uniform texturing start and a controlled pyramid distribution. monoTEX moderating and wetting agent is operating far below the boiling point of its components and behaves almost ‘linearly’ towards temperature and alkali concentration. It also has very short process times of less than 15 minutes. The tuning of the complete process sequence with upstream and downstream processes enables the monoTEX user to achieve efficiencies beyond 20%.

Applications: IPA-free texturing of monocrystalline Si-wafers.

Platform: Moderating agent for IPA-free alkaline texturing of mono-crystalline cells. Application on RENA’s  BatchTex batch equipment. Texturing times of less than 15 minutes, bath lifetimes over 40 runs and >95% tool uptime are claimed to provide a very competitive footprint.  The elimination of IPA from both the exhaust and fluid waste streams further supports TetraSun’s focus on cost of ownership (CoO) concerning both environmental and manufacturing cost, according to RENA and TetraSun

Availability: September 2011 onwards.